Photograph of a multi-S-trap plumbing fiasco Plumbing Drain Noise FAQs
Frequent questions & replies on plumbing drain sounds

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Plumbing drain noise diagnostic FAQs:

Frequently-asked questions & answers about the types, causes, & remedies for plumbing drain noises & sounds.

This article series explains how to determine the causes of plumbing drain noises, and we refer to key companion articles that assist in that diagnosis, and we include plumbing noise cures.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Q&A on How to Diagnose Sounds of Gurgling or Other Noises in a Building Drain Piping System

Photograph of a plumbing vent blocked by a visiting frogReader Questions & Answers about Plumbing Drain Sounds posted either at the end of this article or at the topic home PLUMBING DRAIN NOISE DIAGNOSIS - be sure to review the drain noise causes and cures given there.

On 2018-04-29 by (mod) - thumping noise about every 2 seconds

I would look for a piece of equipment somewhere inside or outside the home - equipment that is running, making noise, and transmitting that noise into the home mechanically.

On 2018-04-28 by Rich

I am getting a little thumping noise about every 2 seconds continuously through the main drain line of my home. It's non stop and goes whether there is running water or not.

Every time that it makes the noise I can feel it vibrate the drain line with my hand. I've been in the house for 14 years and the noise just started about 2 months ago. Can't figure this out.

On 2018-04-04 21:49:34.819975 by (mod) -


I've heard a tapping noise in a wall behind a tub or shower when there was a water leak that drips in that space. Sometimes such leaks occur only when the tub or shower faucet is "on" or opened.

I'd look below that area or in a plumbing access opening if there is one (or when you make one) for moisture or leak stains. A bit of invasive inspection will enable you to find the trouble and if it's a leak (as we suspect), fix it now before the trouble becomes a costly mold remediation job.

On 2018-03-26 16:02:51.280024 by Jen

I hear a tapping noise in the wall behind the shower. This is on the second floor with a roof above it so I’m not sure ... do you think it’s the plumbing or something from the attic or roof? It’s very quiet and seemingly random like it could be drip drip drip dampened by the walls or just tap tap tap. Driving me crazy and husband just gets annoyed when I ask for help with it.

On 2018-03-05 14:14:19.034397 by Joe

For the past few months, I have noticed that every time we flushed our second floor toilet, we hear a loud banging noise that comes from the drain pipe and not from the water fill line. The
noise is louder when solid waste goes through it. The noise is like an echoing bang.

How could we remove this annoying noise? Would it cause more serious problem if we just let it go? Thank you.

On 2018-02-28 21:53:26.427916 by AH

Thank you very much for your help.

On 2018-02-26 23:14:44.317592 by (mod) -

Possible? Yes. Funcational and proper and safe? No.

On 2018-02-26 22:34:23.462427 by AH

Thank you. Is it possible that they used the sink drain as the vent for the toilet? Or do they just share a vent?

On 2018-02-26 22:07:58.667292 by (mod) -


Gurgling drain noises typically mean a drain is blocked or improperly vented. A blocked or improperly-vented drain needs to be repaired, preferably before there is an unsanitary sewage backup in the building.

Gurgling drains can be fatally unsafe if the loss of water from a plumbing trap (due to inadequate venting) permits sewer gases to enter the building. Sewer gases contain explosive methane.


McGeehan, Patrick. "Con Edison and New York City Are Faulted in East Harlem Explosion." The New York Times (2015).

On 2018-02-26 05:39:42.342719 by AH

I live in an apartment in NYC where the bathroom & galley kitchen back up each other, against a common wall. When the toilet is flushed there is gurgling in the kitchen sink drain- is that legal, &/or safe?

On 2018-02-07 22:42:01.383784 by (mod) -


It might be possible to excavate the soil pipe trench, install solid (maybe concrete walls and top) reinforcement over the piping so that it's not affected by over-traffic - that might also reduce the chances of breaking the sewer line. Or replace under-specified sewer piping with the proper weight and strength pipe rated for under drives (sch. 80?)

On 2018-02-07 22:40:40.079072 by (mod) -


If you still get sewage backups then the problem hasn't been identified correctly. Pumping the septic tank will never fix sewage backups, just defer them for a few days. You need to know if the issue is damaged sewer piping or a failed drainfield. You might start at SEPTIC SYSTEM INSPECTION & TEST GUIDE

On 2018-02-06 20:19:35.387616 by beoffwith you

I have a plastic soil pipe outside serving an upstairs bedroom cars passing the house run over a road access hatch and the drum sound travels all the way up the pipe and into the house where there is 1 meter of soil pipe running to the toilet is there any way that I can stop this constant noise inside or outside the house

On 2018-02-06 20:18:06.088036 by Shirley R Edwards

I need assistance about a possible vent problem. I had my septic tank pumped, my drain fields cleaned and my lines cleared of clogs, ut i still get back ups after s few days

Question: Why do Our Drains Gurgle When the Heat Pump Switches to Cooling Mode?

When we switch our water source heat pump from heat to cool, the bathtub drains periodically make, loud, gurgling sounds.

What is the cause and how do we cure this problem ? We are on well water & we do have a septic system. - G.B.

Reply: Check that Heat Pump Condensate Drain First

A competent onsite inspection by a plumbing or HVAC expert usually finds additional clues that help accurately diagnose a drain gurgling noise and heat pump problem. That said, here are some things to consider:

I am just speculating wildly, but a plausible explanation is that the heat pump condensate line may be draining into a pipe that is transmitting noise back to your tubs. If you're sure it's gurgling and not a vibration from something mechanical, that's my first guess.

More obscure: if the condensate drain (cooling systems produce condensate by taking moisture out of the conditioned house air during the cooling cycle) is not properly piped, a fan coming on could cause a vacuum or backdraft up the condensate drain line that might also make noise - but I'd think you'd hear that in either heating or cooling mode, while in contrast, your heat pump would only be producing indoor condensate in the air handler when it is in cooling mode.

Question: Vacuum breaker found under the kitchen floorboards

We are currently renovating a victorian house and found a strange machine under the kitchen floor boards. After reading your article,it seems what we have is a vacuum breaker,so thanks for the info. - Anon

Reply: hidden traps, vacuum breakers, grease traps, drain troubles

Thanks for the tip. Indeed hidden plumbing traps, vacuum breakers, grease traps, etc. can add to the time and trouble we encounter when tracking down drain noises, odors, or clogs.

A photo would be a help to other readers. If you can provide a picture of what you found, send it to us using the CONTACT link found at the left of any of our web pages.

Question: Drain glug glug, klug klug, & whirring noises: why do I hear a clug clug sound when the toilet is flushed?

Why do I hear a "clug,clug "sound when the toilet is flushed? The toilet is upstairs and the sound is coming from the basement on the other side of the house - Karen Canning

I have slow drains and saw a 1 foot x 1 foot soggy spot over my septic field. When one person is in the shower for more than 15 minutes (teenagers) or if the washing machine is running, we get the glug, glug sound. Toilets do not like to flush right away, they fill, then suddenly drain out. Suggestions? - Susan in Florida

We are a single family two story (plus basement) home in central Connecticut with city water and sewer. Yes, our home has a proper through-the-roof plumbing vent pipe. Recently my wife noticed a strange whirring sound coming from the (upstairs) bathtub drain.

Honestly, I thought she was nuts, but sure enough now I notice it also. Think of a muffled police siren; whirr-whirr-whirr. Lasts about 5 to 10 seconds, then may or may not happen again within minutes, and so on.

Any time of day; a few nights back I woke at around 3:00 AM and, while using the bathroom, there it was. I had not yet run any water, flushed the toilet, etc.Any hints as to what could cause such an odd sound to emanate from the bathtub drain? It is the only fixture in the house where we have noticed this.

I am confidant that it is not related to the hot water heater which is of the indirect-fired type.

Our high-efficiency gas-fired condensing boiler has a small motorized condensate pump which empties into the main branch (cast-iron) drain pipe in the basement, but I am pretty certain the noise is not coming from that either.Home was built in th 1920's with typical plumbing for that era. Bathroom was remodeled two years ago, so bathtub and related plumbing is all relatively new. - Carmine in Connecticut


Karen: if you hear a "klug klug" when the toilet is flushed it may be a blocked or missing plumbing vent. Sometimes a slow partly blocked drain will do that too. Carmine:
The whirring sound from the bathtub drain may also be due to a blocked vent, especially if it happens when the toilet is flushed or other drains are in use.

A home like yours, built in the 1920's may also not have plumbing vents provided at all fixtures, or the vents may be undersized or even clogged. Even if some fixtures were updated it would be unusual for 100% of their drain runs and vents to have been replaced.

That glug glug glug sound along with slow drainage is often water draining slowly past a blockage somewhere down the septic or sewer drainage system.

If it were a venting problem unless something just clogged a vent, it would have always been present. Combined with the wet spot in the yard sounds like a saturated drain field but until you do some investigating we don't know if it's as inexpensive as fixing a broken or clogged pipe, or replacing an entirely saturated failed septic drainfield.

CLOGGED DRAIN DIAGNOSIS & REPAIR can help diagnose tracking down a clogged drain and distinguishing between a local drain clog and system drain clogging: knowing where the clog is located will define the type of drain repair needed.

SEPTIC SYSTEM INSPECT DIAGNOSE REPAIR can help you diagnose what's going on with a blocked or partly blocked septic system or drainfield. .

Question: Bubbling & bubbling noises at basement floor drain

My house is about 40 years old, and we did remodeling 3 years ago. Starting last week, I noticed a bubbling noise lasting a few seconds from the basement floor drain. This noise happens every minute or so without obvious reasons, even when no water in use. All draining of fixtures seem to be working fine, no slowness or noise. No gas odors smelled. Do you have any idea what might cause the noise and how to fix it? - Peter in Toronto


Bubbling in a basement floor drain might be a slow building drain that is backing up; even if you haven't just run a plumbing fixture, if, for example, you flushed a toilet earlier and all of that wastewater emptied just fine, but really just ran into a larger-diameter sewer pipe under or outside or still near the building, where then it ran into a partial blockage, what would happen is that the wastewater would drain past that blockage slowly, causing gurgling or bubbling sounds. When the noise seems to have stopped, go flush a toilet and wait a few minutes to see if you hear the sound beginning anew. If so we may be on to the right diagnostic.

Question: Air handler A/C condensate drain & glugging sound in bathtub drain

My air handler seems to be constantly draining and I'm getting a glugging sound in my upstairs bathtub drain. Is it related and is my air handler close to frozen?

I don't see any leaks in the attic although I haven't gone all the into the attic and inspected the air handler. I did close most of the air duct vents upstairs to force the cold air downstairs, could I have possibly froze the air handler considering it's 110 most days and the AC is almost constantly running? - Randy in Mesa


Randy your note suggests perhaps your air conditioner condensate is draining improperly into a plumbing vent line and that in turn that line (or the condensate drain itself) is partly clogged. Or you have a separate problem with a slow bathtub drain or bad bath venting.

If the glugging sound occurs when you flush a toilet in that same bathroom I suspect the drain or vent is clogging.If your air handler cooling coil was iced over you'd see the effect as loss of airflow out of the air supply registers, or you can see the icing and frost by inspecting the air handler interior (power off first for safety).

Question: Loud drain noises when toilet is flushed

We moved into our home 6 years ago and whenever the ensuite toilet is flushed we can hear the water very loudly go down through the pipes.

Recently, whenever ANY toilet is flushed or a sink drained on the 2nd floor we can hear the water travel down the pipes. What is the cause and how can we fix it? Thank you. - Cathy in Calgary


Kathy your question is a common and important one about how to avoid plumbing drain noises in buildings.

I've added my suggestions and some photos

in PLUMBING DRAIN NOISE DIAGNOSIS. Please take a look - just above this comment box - at your question and my reply, and let me know if you have further questions or suggestions for us or other readers. Thanks. DF.

Question: Glub glub when my shower/tub combo drains, sounds at the toilet

I live on the first floor of a small apartment building. When my shower/tub combo drains, I hear a "glub glub" sound like it's coming from the toilet. Today, I walked in to find that the bathmat was soaked and there were remnants o something brownish that had backed up into the tub. I can't figure out how/when it happened, though.

Any idea what's going on and what I should do? (My landlord will probably tell me to fix it or pass the cost onto me.) - Anon


Anon the glub glub sound you describe is typical of a partially blocked main drain or a blocked plumbing vent system. It sounds as if you have a blocked drain and sewage backup into the tub. Your lease will most likely describe who is responsible for - keeping the plumbing system working
- cleaning up unsanitary sewage backups due to plumbing problems

Question: Sound of water constantly coming down pipes in master bedroom, maybe from upstairs A/C ?

I have lived in on the 12th floor of a 13 story building, constructed in 1928, for 10 years. About a month ago, I started hearing what sounded like water constantly coming down the pipes in my master bathroom.

The problem was noted as likely being from my upstairs neighbor's ductless air conditioning system, which apparently cools via pipes and flushes water down the same pipe as the toilets. No fix has yet been arrived at for that problem. In addition, the air conditioner contractors who came to look at the issue indicated that such noise shouldn't be audible since the pipes in question are cast iron.

At the same time, I can now also hear my upstairs and downstairs neighbors' use of their plumbing - from toilet flushing to tap use. This seems odd, not only because I've never heard it before in all the years I've lived here, but also because the pipes are cast iron. We did a "test" and you could hear the noise of the toilet on the first floor flush all the way in my unit - 11 floors away!

I am being told by my building super that such plumbing noises are "normal," but that is not consistent with my experience nor, I believe, the materials in question.

He thought there may be air in the system so turned the water supply off then back on, but it made no difference. I am finding it difficult to get any response from my building management. I am going to get in my own plumber but wondered if you had any ideas? - Nicola


Nicola, A noise of water running pipes can be annoying but my first worry would be an actual leak;
And I agree that it's usually tough to hear water running in cast iron piping.On the other hand, noticing a change is usually an important diagnostic. See if you can track down what happened a month ago - a service call, a plumbing change, something.

That'll be a useful clue.I don't think air in the drain system would explain drain noises; there's always air in the drain system.

Reader Follow up:

Thank you for your response. On the changes, one thing that occurred right about when I started hearing the noises - and I may not get the terminology right - there had been an uncharacteristically huge rainstorm here and the waste pipe for the building was not big enough to handle the capacity so there were overflow problems, like water running out of people's toilets on the first floor (apparently the pipe doubles in function; I live in a large city).

That pipe for the building was replaced, I want to say from a 6 inch to an 8 inch; I could be wrong on the size but I know it was increased. I asked the building super if there could be a connection, and he did not appear to think so. I have also checked with one of my downstairs neighbors and he does not think he perceives plumbing noise other than from inside his own unit.

The only other apparent "change" was that my upstairs neighbor who is apparently not usually around in the summer (though she has lived above me all 10 years I've been here) started using this ductless air conditioning system that continually flushes water down the same pipes used by the toilets.

I wonder if this could have precipitated a problem? What is most puzzling to me is that now my neighbor has been requested to turn her air conditioning system off, it is definitely apparent that I am hearing not only toilets flushing but also the use of running water, such as from showers - and loud enough to be heard outside the bathroom. In other words, the noise does not appear to be confined to one particular pipe.

Since my first query, it has since been suggested to me that perhaps I have a dried trap (maybe due to a clogged vent) which is magnifying the noise of water through the system. I am still in the process of getting a couple good plumber recommendations. In the meantime, I don't know if you have any further opinion based on these facts? Thank you. - Nicola


Two items to check further:It is trivial to check for the effect of a dry plumbing trap- just pour a pint or more of water into every plumbing fixture to be sure every trap is filled. I am not considering the possibility that you have a drain with no trap at all or an s-trap that loses it's seal because you report your noise complaint is a change.About sound transmission changes around a building drain, if there was insulation that has become wet or was removed you may hear more drain noises. Check for those conditions.

Question: Clothes washer drain noise into bedroom wall piping - should we insulate the wall?

I recently moved into a new-build apartment. There is a flat above me, and the residents just moved in. Their utility room is directly above my bedroom, and I was up four times last night as their washer drained water into the pipe, which runs through the wall in my bedroom.

The builders have told me it's a 6-inch pipe, which seems massive for one washer and maybe a sink!

They are suggesting pumping insulation into the wall, but I'm worried - will this fix it? Why did they install such a big pipe? Would that be making it more noisy than it needs to be? - Emma


Emma, the large diameter drain may be because it's carrying other fixtures, or to avoid clogging; in any case, insulation can reduce noise transmission.

Question: Why do my toilets go glub-glub when the shower is on?

What would be the cause? I get the "glub-glub" in my toilets while the shower is on, shortly followed by the shower backing up and the toilet not flushing.

I have snaked the outlet towards the septic to no avail. I'm sure that the phone call to the plumber will follow, but would like some idea before I look like a complete idiot. - Eric


Eric: that glub glub noise followed by clogged drains means most likely that you have a blockage or partial blockage further along in your main sewer line than your plumbing snake would reach.

Question: Gurgling or glub glub sound in drains and slow drainage - septic tank was just cleaned and I heard water pouring back into the tank ..

i just had my tank cleaned out 2 months ago & now i think, but don't know how to tell if there is a problem with building vents. i getting a Gurgling or "glub glub" sounds in the drains and slow drainage, we also have had very heavy rains this month, after the tank was pumped out i could here water pouring back into the tank,

how can i check the vent pipe from the roof to the basement, there r no openings from the roof to basement what to do? - Tony


Tony, the bad news is that when water pours back into a septic tank during pumpout that suggests that the drainfield is saturated, not working, and may need a costly replacement. Sometimes, especially after heavy rains, surface runoff can be saturating the drainfield

. In that case the "fix" may not require drainfield replacement, but rather the installation of an intercept drain system to keep surface and subsurface runoff away from the septic drainfield.

Your slow drain problem can be from a blocked main drain or from a flooded septic tank and backing up drainfield.

Question: dripping sounds in drains above my apartment

I moved into an apt. on the first floor 3 months ago. I have been recording dripping sounds (about 1.5 drips on an average per hour)and notified the manager to no avail.

When someone has come to listen (3 times) of course nothing happens but they only stay 10-20 minutes. The dripping sound is over the toilet and sink area.

No apparent leaking coming from the under-the-sink or toilet areas of the apartments above me, according to maintenance. No crawl space above 1st floor apts.; only 2nd floor apts. have crawl space between their ceilings and roof. I've been told the only way to investigate is by cutting a hole in the wall.

I imagine the cost to do that is keeping them from further action. The dripping sound is loud and sounds like water dripping on wood, or manmade product.

On an average it drips about 1.5 times per minute. It can drip 40-50 drips/second and go 20-30 minutes without dripping at all.

The complex is approximately 12 years old. A single boiler for each building. Each building has approx. 20 1-bdrm apartments. The buildings are 2 stories, 2-sided, 10 apts on each side = 20 apts. in each building. I've been in other apartments on both the lower and upper floors. No one else in my building seems to have this problem. Any ideas? - Jean Smith


Jean, what you describe sounds like a slow leak into the ceiling over your bathroom. A small leak may take some time to show up as stains on the ceilings or walls below. Sometimes there may also be a leak that drips into a drain pipe itself - that'd be lucky in that the risk of hidden rot, mold, or other damage is less.

Question: Glub glub sounds on the kitchen sink when the water is turned off

In my 16 year-old house, several months ago I started hearing gurgling or "glub blub" sounds on the kitchen sink when the water is turned off. If I only run the water to a few seconds then I don't hear the sound. But if I run it at full speed for a minute or longer, after all water is drained down the pipes I hear the sound.

I recently had a new garbage disposal and faucet installed, and the plumber suggested I just needed some drano to clear the pipes for that noise to go away.

I used foaming drano last night but the noise is still there. The water drains fine, so I don't think there is any blockage, but that loud blub sound for a minute after every faucet usage is quite annoying. Any ideas? - Zvez


The glub blub sound you describe often is a hint that a drain is partly clogged in your system. If the drain blockage is pretty far from the sink itself, you may find that you can fill and drain the sink just fine - as its water is simply filling the open pipe between the sink and the blockage.

From there the water drains slowly past the blockage, making the sound you describe.We hear similar noises when the building vent piping system is clogged - in this case the noise is caused by air entering the piping as the fixture is draining.

Question: Gurgling from kitchen sink, snaking the drain didn't help

Hello, appreciate the info. on your site! About 6 months ago, I cleaned out the pipes under the sink due to a very slow leak from our garbage disposal. The leak was due to a bad pipe seal... A few months later, we started to hear the gurgling sound coming from our kitchen sink (sometimes even after just a little water has passed through).

I do also think that there's something with our A/C since over the summer there was some leaking of water coming from the outside drain (it's tied to the inside drain in our guest bathroom though and guessing it should only drain there?).

Long story, short, I snaked the drain from the main sink pipe (the point just after the pipes from garbage disposal and 2ndary sink converge) and it did not help. I'd used the blower 3 or so months ago (to blow air through the pipes)... and this seemed to resolve the issue for a week or so. Any help is appreciated! - Joey


Joey your description suggests that there may be a partial drain blockage on the main house drain between the building and the septic field or sewer line. A blockage can also send water backing up from the outside drain as you described. If you have a septic system, the problem may be in the drainfield. Check the levels in the septic tank if you're not on a sewer system.

Question: drain noise from water running down sink tailpiece into the drain trap - how do I fix this?

Just got a new vessel sink installed and trap/drain under sink had to be replaced due to reconfiguration. Lots of noise from water running down the tailpiece and into P trap. PVC used. How do we fix this? - Pam

Reply: check first for proper venting, then consider sound insulation for plumbing drains


First you will want a plumber to confirm that the new sink installation has been connected properly to a plumbing vent stack. Second, presuming the piping is all correct and the drains are not blocked but run freely, if the drain noise remains a local problem in the building, you can consider adding sound insulation around the drain piping.

Watch out: while it's trivial to box in and insulate a building drain, be sure to provide an access cover to permit inspection of the drain for leakage and to permit the trap to be removed, cleaned, replaced. We don't want water from a leaky trap spilling into the insulation enclosure lest we risk a mold and rot problem.

Question: foul odor from sump pit smells like sewage

I have two issues that may (or may not) be connected. There is a persistent foul smell that comes from our sump pit- it smells like sewer water and occasionally really smells up the basement with this foul smell. I have had the main line that exits the house to the main sewer line in the sewer scoped and there was no apparent leak. . I ran a hose at full throttle down the vent and had no return so it seemed like it was all clear.

The sump pit hose that runs to the main line has a check valve. The sump pump drains/ejects rain water and also water from our washing machine that drains into the pit. When the sump pit ejects its water it enters the main line out to the street (this is code in my village). However, when the sump pit activates I can hear a gurgling sound from my kitchen sink. There is no smell from the kitchen sink however. - David


A smelly sump pit may be due to sulfurous groundwater, a drain line leaking into the sump system, or gases backing up from the sewer line. The gurgling under the kitchen sink can indicate a partly blocked drain, or if you're confident that the drain is free, a venting defect.

Even running water down the vent line to show that it doesn't seem blocked won't detect improperly routed plumbing vents. For example if a sink or other fixture is too distant from the vent stack it may not vent properly and you'll get that gurgling in the drain. Also if your kitchen sink is installed in an island countertop, special vent piping arrangement is needed to vent properly.

Question: drain noise complaint: glub glub from kitchen sink drain when washing machine empties

A few months ago we started having loud "glub glub" noises from our kitchen sink drain when the wash machine empties. House is 6 years old (we built it), all sink drains are properly vented with Studor mini vents, and we have a septic system which has not been emptied.

The kitchen drain is the furthest away of all the drains, and washer drain pipe joins the main drain pipe immediately downstream from the kitchen drain pipe. No sounds have been observed from any other sinks, toilets, etc. However, there are a few other wacky occurrences which may or may not be related.

Recently we had a problem with one of our toilets not would swirl and fill up with water, and very slowly go down. I attempted to flush nearly 10 times holding the handle down until it finally went and have not seemed to have problems since.

Also, a few summers ago I noticed a sewer smell in the back yard in the vicinity of the septic cover, and the location of the perceived odor changed, seemingly with the wind. I could not find a spot on the ground that was wet, muddy, or had any odor, but I could often smell it in the same area

. I had wondered if the ground could have settled enough to crack the pvc pipe that leads from the house to the septic tank and cause a blockage. Last summer, though, I didn't smell it once. I've opened the cover a few times to see if it looked full, but it didn't.

Our neighbors are plenty far away so I know it couldn't have been from them. My wife runs a daycare in our home, so she uses plenty of water, and I've wondered if a child may have flushed an object down the toilet. With everything I'm reading on your site (which is great, by the way) I'm not sure the first thing to check short of calling a plumber. - Mike

Reply: good news, bad news, about noisy sink drains when washer empties

Mike, it's an axiom in diagnosing drain noises and sluggish drains, that if the problem is a basic design and installation one, most often (not always) you'd have had these complaints since the building was first constructed. I say "not always" because some plumbing installation mistakes such as improperly sloped drain piping or use of improper tees and wyes in drain connections can work ok at first but may eventually lead to drain clogging. Still, those mistakes usually show up early in the life of the building.

But if the slow plumbing drains and plumbing drain or vent noises show up much later in the life of a building, our first guess is that either a drain has become clogged or partly clogged, or if the home is connected to a private septic system, the septic system is in failure mode - slowing or even refusing to accept effluent outflow from the septic tank.

On occasion, the good news is that the problem is just a blocked or damaged drain or vent pipe. The expensive problem is a failed septic.

Take a look at CLOGGED DRAIN DIAGNOSIS & REPAIR for suggestions on how to proceed.

Question: The neighbor's roof vent is so noisy we hear the toilets flush next door

We have a covered patio that faces the side of our neighbors house. We can hear his toilet flush through the vent pipe on his roof. Is that normal? We have never noticed it in other houses we have lived in where our outside space was in close proximity to our neighbors bathroom vent pipe.

It is so annoying and embarrassing when we are outside. Is there anything we can have our neighbor do to eliminate the noise? Thanks, Bonnie


Bonnie, Presuming that there are normal distances between your patio and the neighbor's plumbing vent roof pipe, what you describe is unusual. I wonder if perhaps the neighbor has

You might ask the neighbor if flush noise is a problem inside their own home, or if there is a drain problem - if the answer is no to both cases, ... well I'm not sure what recourse you have without having to ask the neighbors to reroute their drain vent to another roof location that sends less noise your way. I'm continuing to research and will report further here.

Question: Drain Noise Complaints Traced to V-200 Anti-Siphon Valve Installation

Just bought a 40 year-old house. Sump pump drains into city sewer. V200 plumbing installed on drain pipe up in the rafters about 16 inches above pipe. After the sump pump turns off a loud burping or gurgling sound is heard. It lasted about 10 seconds. I changed the V200 for a new one and the same sound occurs but now for only 4-5 seconds. Any ideas? thank you - Louis

Sorry. In that last comment i shouldn't have said rafters but rather between the basement floor joists. I also meant a V-200 plumbing vent (also called anti-siphon I think) - Louis

There is ONE vent coming out through the roof for the plumbing in this house (two bathrooms and one kitchen) while the bathroom in the bedroom has a vent that terminates in the attic. The kitchen sink also has one of these V-200 things. Any way to stop the noise without venting this pipe through the roof? Given the construction it wouldn't be easy. Thanks for your help Dan

Reply: V 200 cheater vents

Louis the V-200 or "cheater vent" is intended to allow air INTO the drain line when needed, and may be making noise during that function - as water runs down your drain line, and presuming that your building lacks proper vent piping to outside above the roof, the V200 is breaking the vacuum and allowing air into the drain as needed.

Louis a plumbing vent that terminates in the attic should have been run to outside the building to avoid a potentially dangerous sewer gas problem indoors. It's common for vacuum-breaker "cheater vents" like the V-200 to be retrofitted in older buildings where the original plumbing did not include or did not include enough plumbing vent piping.

The V200 - which is indeed an anti-siphon valve) and similar products, are a stopgap or retrofit measure that we use when there is just no economical way to get a proper plumbing vent installed. But I don't blame the V200 anti siphon vent itself for the noise problem.

That's a feature of the type and location and routing and size of plumbing fixtures and drains. In my experience noise complaints around anti siphon valves are rare.

You could try moving the piping and anti siphon valve a bit, or you could try some sound insulation around it - just be sure to leave a way for air to get TO the anti siphon valve or it will stop working.

Question: gurgling noises at drains in new home

(Apr 11, 2014) Geraldine Higgins said:

We live in a new house (14 months old) ever since we have lived here with have had problems with the plumbing.

The main problem we have is that all of our basins in en suites and the bath make the most horrific gurgling noises when the water is draining away and we have the same problem with the sinks in the kitchen and utility room. Can you please advise what the cause could be.

(Nov 20, 2015) Anonymous said:
Why does the shower drain bubble and gurgle when I run the water in the basin



Look for a blocked or missing plumbing vent serving the fixtures OR a partly-blocked main drain.

Anonymous: same answer as above.

Question: running sand noise at toilet flush

(May 12, 2014) Anonymous said:

when the toilet is flushed sounds like sand running through the line


(May 12, 2014) (mod) said:

Sand sound is one I've not come across vis a vis toilets, Anon. Perhaps it's a hissing sound? Could there be an air leak in a vent pipe? Or a water leak or spray in the toilet tank? Lift the lid, flush the toilet and let me know if the controls are doing something odd.

I suspect that the noise you hear is a hissing, perhaps of water or air in the toilet flush tank or cistern during fill-up.

Question: problems with island sink drain in kitchen

(July 2, 2014) Bud Kent said:

Our house is about 10 years old. We seem to constantly have the plumber come to clear the kitchen sink line.

This sink is on a peninsula and the line is also connected with our washing machine. We too have loud gurgling when the washer is in rinse mode. It seems like when this happens as bad as it is now we soon will have to have the plumber again.

He was just here 4 week ago. We flush nothing down our sink or disposal at all. Seems that based on previous discussions it will likely be a clog much further down the line? We were told the venting may be inadequate but the builder insisted otherwise.



Island sinks require special measures to properly vent the sink drain - into which the dishwasher will also empty.

See ISLAND SINK PLUMBING VENTS or search for that term.

My cousin Neal B. had this problem in a new home. It was traced to improper original drain line installation work that failed to slope the drain (1/8" to 1/4" per foot) piping.

Gurgling is an indication of a partly blocked drain.

Either the plumber has not found and cleared the clog effectively, or you have a recurrent clog problem caused by a problem such as

- bad drain slope
- crud flushed down drains
- a broken pipe
- root invasion
- improper pipe routing, bends, elbows

Question: faint flush noises from shower drain - caused by next door neighbor

(Sept 23, 2014) Ann said:

I have a house built in the 70s and I've noticed faint flush drain noises that seem to come from the
shower drain in my home. The noise appears to be the next door neighbor's flushes. These are both
single story homes, mine is a higher elevation. Does that mean our plumbing is somehow connected?



Your neighbor's plumber may find a clogged or blocked plumbing vent.

It would be improper and unusual for your separate home to share plumbing with your neighbor.

Question: condominium odor complaints after flooding & pipe noise complaints

11/8/2014 Anonymous said:

I live in a ground level in a 38 years old building , the condo was renovated before I buy it , I noticed when I close the bedroom door , that there is bad smell in the room, that I wake up and open the door , knowing that I knew after I bought it , that the condo was flooded and fixed after, so what is the reason behind that smell, if the condo was fixed?

also between 6 am and 9 am , I hear strong noise when the water pipes start to stretch behind the bedroom wall, so what kind of insulation shall I put? also shall my realtors n seller have informed me of these stuff before the purchase?


Anon if the condo was flooded and not properly remediated there could be a remaining sewage or mold reservoir in walls, floors or ceilings.

Thermal movement of water pipes causes noises as you describe: that's something that can be reduced somewhat by insulating the wall cavity if it's not already insulated, but wait: a more effective approach may be available depending on what exploration is needed to find and remove the odor problem.

If wall cavity exploration finds contamination therein, the walls will need to be opened, cleaned, and re=insulated.

At that time use noise suppressing pipe supports and give adequate cleareance around piping thorugh wall framing to stop the noise entirely.

On 2015-03-04 18:16:49.212950 by Joe

The floor drain in my basement emits a gurgling sound only when the heat pump comes on. Any ideas?

On 2015-02-02 16:14:52.243890 by (mod)

Mike I'm unclear where you're seeing air backdrafting. If you mean from the bowl then it sounds as if there is a drain or vent blockage or the tank is not sending enough water to re-fill the bowl.

On 2015-01-31 17:00:38.152280 by Mike

after flushing the toilet I get a backdraft of air from the toilet. It is a septic system.

On 2014-12-08 19:36:21.134980 by (mod)

Anon look for a clogged drain first and inadequate venting or missing venting second. When the fixture that gurgles is just one sink, the problem is probably in that fixtures drain or vent piping rather than later on in the system.

On 2014-12-08 17:33:33.261550 by Anonymous

bathroom sink gurgles after sink drains. used drain cleaner; gurgle got louder. no other drain in house makes noise, just one sink. odd.

On 2014-12-08 17:29:26.096420 by Anonymous

Dempsey Helms

On 2014-12-02 22:22:08.744240 by (mod)

Sal if the noise is brief and stops shortly after closing the faucet,

in ARTICLE INDEX see WATER HAMMER NOISE DIAGNOSE & CUREIf the noise is continuous one would think water must be running, leaking somewhere, OR you are mistaking water running down a drain for noise in the supply piping.

On 2014-12-02 21:51:17.152720 by Sal

Yea tell me about it :). I'll let you know once I find a solution. Thanks for the feedback.

On 2014-12-02 21:43:58.584260 by (mod)

How interesting Sal. Usually gurgling noises are either- a partly blocked drain
- air in the water linesand occur when water runs not when it is not running.I'm baffled.

On 2014-12-02 21:29:08.010980 by Sal

I have laundry faucet that keeps making a continuous gargling noise when I close the faucet handles. When they are open the sound disappears. Also when diagnosing I realized that if I plug the head where water comes out the noise stops. In addition, I have a medal rod connected to the back of the faucet and going down to a ground pipe which drips water into it (I learned that's used to keep the ground pipe from drying up and making a smell...)I was thinking I might need to change the seat to fix it... Let me know what you think.Thanks

On 2014-11-08 16:03:37.548450 by (mod)

Anon if the condo was flooded and not properly remediated there could be a remaining sewage or mold reservoir in walls, floors or ceilings.

Thermal movement of water pipes causes noises as you describe: that's something that can be reduced somewhat by insulating the wall cavity if it's not already insulated, but wait: a more effective approach may be available depending on what exploration is needed to find and remove the odor problem.

If wall cavity exploration finds contamination therein, the walls will need to be opened, cleaned, and re=insulated. At that time use noise suppressing pipe supports and give adequate cleareance around piping thorugh wall framing to stop the noise entirely.

On 2014-11-08 15:52:35.181160 by Anonymous

I live in a ground level in a 38 years old building , the condo was renovated before I buy it ,

I noticed when I close the bedroom door , that there is bad smell in the room, that I wake up and open the door ,

knowing that I knew after I bought it , that the condo was flooded and fixed after, so what is the reason behind that smell, if the condo was fixed?also between 6 am and 9 am , I hear strong noise when the water pipes start to stretch behind the bedroom wall, so what kind of insulation shall I put? also shall my realtors n seller have informed me of these stuff before the purchase?

Question: loud washing machine noise from pipes when flush the toilet

(Sept 28, 2015) Jeanette said:
We've lived in our house for over 7 years, our house is 22 years old. All of a sudden the last couple of weeks every time you flush the toilets, use any sinks, run the shower, washer or dishwasher (pretty much use the water at all), the pipes make loud noises, almost like an old washing machine noise. Any idea what this could be and why all of a sudden it is happening?


If the noise is coming from the water supply piping please search for WATER HAMMER NOISE as that may be the trouble you're having.

If the noise is from drain piping look for a clogged drain or sewer pipe or a failing septic system.

Question: drains back up in toilets and sinks and shower when the clothes washer is draining

(Oct 2, 2015) Joyce said:
i run my washer and when it drains water backs up in toilets sinks and shower . Why?


It sounds as if the building drain is clogged.

Question: rhythmic thumping sound from garage when toilet is flushed

(Oct 5, 2015) Gwen said:
Hi,when we flush our toilets there is a rythmic thumping sound coming from our garage until the toilet stops. Thanks for any advice!


Please search for WATER HAMMER NOISE

Question: low frequency droning noise

(Nov 9, 2015) dee said:
I have a low frequency droning noise for Years slowly driving me crazy!please help? The noise is constant.



Question: gurgling in bathroom sink

(Nov 20, 2015) heather murphy said:
I have gurgling in bathroom sink i have a s trap under sink.But below about two feet i have a P trap i am wondering if could be cause of problem,oh yes i ran a new air line to existing line but this has not solved the problem.Please send back info on what i could do next.


Double traps are likely to drain poorly and might explain gurgling - if a drain is partly clogged.

But an S-trap usually was installed where the drain line was not vented - which is both a common cause of gurgling drains, AND which risks loss of water in the drain trap that in turn risks dangerous (explosive) and smelly sewer gases venting back into the building through a dry trap.

I'm not sure what new air line you ran, but if the distance from trap to a working vent is too great or piping not properly routed the drain may still siphon, lose water, and smell, as well as gurgle.

Question: fixing plumbing noise transmission in a condominium

(Nov 28, 2015) C loan said:
We live in a condo on the second floor... The owners downstairs have gutted their condo...this includes bathrooms directly below ours... We are now hearing our toilet flush down the shower drain and the bathroom sink as well ... Am sure the same thing will happen once their second bathroom Reno begins... Please help?


(Nov 28, 2015) C loan said:
We live in a condo on the second floor... The owners downstairs have gutted their condo...this includes bathrooms directly below ours... We are now hearing our toilet flush down the shower drain and the bathroom sink as well ... Am sure the same thing will happen once their second bathroom Reno begins... Please help???
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Question: gurgling sink drain, slow drainage then dishwasher leaks

(Jan 3, 2016) Lynette said:
I run water in the sink, it gurgles and both (kitchen) sinks feel up with water, then real slowly sink with garbage disposal drains, then the other sink real slowly drains all the time. Then the dish washer starts leeking out the bottom of the door. When I use the dish washer I have no problems with it.



Your kitchen drain is clogged, perhaps a ways downstream from the sink. When the drain backs up water tries to find its way out from the lowest point through which it can escape: in this case the dishwasher or an air vent on the dishwasher drain. When the dishwasher is running its pump is pushing water into the drain.

Question: gurgling drains and slow drains - home with septic system

(Jan 9, 2016) Anonymous said:
I live in the country and have a septic tank which is outside my bathroom window in my yard my toilet isn't flushing properly and my rub and sink are gurgling like crazy just had septic emptied 2 months ago HELP ..



Unfortunately while pumping the septic tank is necessary to maxmize the drainfield or soakbed life, pumping the septic tank will never fix a clogged drain or a failed septic drainfield.

You need some onsite diagnosis to inspect the septic tank, distribution box, sewer piping, and drainfield for blockage or failure.

Question: toilets gurgle and most of the water drains out of the toilet bowl

(Jan 12, 2016) frank said:
once in awhile our toilets will gurgle and most of the water drains out of the bowl. This usually happens at night and in all three bathrooms at the same time. We live in the country and are on a septic system. (last pumped in 2013) Help!


I suspect clogged or inadequate plumbing vent piping and a partial main drain clog. When the plumbing vent is clogged the vacuum created by wastewater flowing into the drain system can in turn draw water out of nearby plumbing traps or toilets. That may explain the low water in the toilet bowl.

Question: slow kitchen drain

(Jan 12, 2016) Jim R said:

My house is laid out with the kitchen closest to the septic system and about 30 feet from the main drain. The rest of the system has the clothes washer next to the hall bath with the master bath sitting on the other side of the wall to the hall bath with the vent to the roof in the general area of the baths and WM. House is about 36 years old.

The kitchen drain has been a problem for awhile, but I don't know if the earlier drain problems are related to the current issue. It runs very slow and if I run the water for awhile it backs up into the double sink. It will eventually drain itself. I used my shop vac to suck stuff out of the drain which helped for a ver short time, after which, running water into it causes gurgling sounds. I figured the clog was further down the 25 feet so I bought a snake which I ran down the entire length multiple times with varying size heads with no appreciative gunk being withdrawn. The other drains in the house seem fairly normal, but they sit 45-50 feet from there the main drain exits the house.

I'm trying to determine if the problem could be vent pipe related or buildup in the PVC main drain. The middle of January isn't opportune for troubleshooting the vent piping which I should be able to clear in better weather and I hate to get someone in to deal with the main pipe if I don't have to.

In addition to my post yesterday, I noticed something I hadn't noticed before. There's a second vent pipe exiting the roof. It appears to be an inch and a half pipe. I checked the basement and it looks like it's about 5 feet from the kitchen drain, running up to the roof. It's hidden above the heat vents so a bit difficult to see.

After everything I've written, I'm guessing right now that the vent pipe has an obstruction. Does that sound probable and is the drain configuration normal?


When a single plumbing drain or fixture is giving drain trouble and other fixtures work well, the problem could be quite local: a clogged trap, clogged drain between the fixture and the building drain, or a local plumbing vent defect such as clogging or missing vents.

Question: gurgling noise when we flush the loo

2016/03/06 David mulrooney said:
When we flush our loo, we sometimes get a gurgle noise, a few times a day but not every time coming from the nearby bath. We live in a first floor flat. Recently had the stack/waste pipe which serves all the flats jet washed thinking it could be blocked. Have also used numerous unblocking chemicals on all our sinks. The waste water is flushing away ok. Yet still get noises, any ideas!



Based just on what you describe, I'd look first for a partial drain blockage that's a bit remote from the toilet itself. Even though you had the lines "jet washed" I'm not sure really what was done, how thoroughly, to what length, nor if the lines were scoped. A camera inspection might show up, for example, root infestation or a partial line collapse that jet washing won't fix.


Continue reading at PLUMBING DRAIN NOISE REPAIR - home, or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see PLUMBING DRAIN NOISE DIAGNOSTIC FAQs-2- more recent plumbing drain noise questions & answers


Or see CLOGGED DRAIN DIAGNOSIS & REPAIR - clogged drains may gurgle or burp

Or see PLUMBING VENT NOISE - since vent problems can cause gurgling at drain lines

Or see this

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