More recent plumbing vent piping & system FAQs:

Often noisy or slow building drains or drain odors are traced to problems with the building's plumbing vent system piping and connections. These FAQs help diagnose and specify the repairs for those annoying problems.

This article series describes how to track down and correct these "gas odors" in buildings with a focus on homes with a private onsite septic tank but including tips for owners whose home is connected to a sewer system as well.

What makes the smell in sewer gas? Sewer gases are more than an obnoxious odor. Causes of gurgling noises at drains, and why some fixtures "gurgle" when a toilet is flushed nearby.

Plumbing Vent Piping Defects May Cause Drain Noises or May Release Dangerous Sewer Gas Odors Indoors

These questions & answers about diagnosing and fixing smells, noises, leaks traced to the plumbing vent system were posted originally

at PLUMBING VENT DEFECTS & NOISES - home - be sure to see those diagnostics.

On 2018-11-12 by (mod) - can I add fixture to the ejector pump pit vent?

That might work if the vent is a drive and not a wet vent.

It's not clear to me what your ejector vent is capable of handling or where it is routed.

On 2018-11-12 by Charlie

I am installing a half bath in the basement and want to tie into the vent line from the ejector pit. My new vent will run vertical about 8', then change direction and run parallel between two joists until it meets the existing ejector pit vent line.

The existing ejector pit vent runs vertical then runs horizontal for about 4 feet and is below the joists, then goes up through the ceiling.

My question is, Can I drop down from between the joist to the horizontal top side of the ejector pit vent?

On 2018-09-28 by (mod) - install a new plumbing vent stack

You could install a new vent stack, even an outdoors one, but the risk and thus unsafe conditions would still be present if an old vent stack is emptying into a roof space or otherwise not vented outside.

So your plumber needs to follow the vent piping to its destination. One can look into the roof cavity from gable ends, from soffit vents, from an opening cut from inside where repairs are easy and cheap. There is no reason to "tear off a new roof" to inspect.

On 2018-09-28 by Katherine - can't find vent leak

Hi I need help. Have some kind of vent leak when weather changes, back half of house fills with sewer gas. Have had multiple non professionals try to find vent/stack.

May not have one or may have been covered by new roof on mobile home. Can we install new vent? I currently have multiple holes in my wall trying to locate old one?

Do not want to tear off new roof to see if vent was covered over etc. Please advise. Rarely odor in warm weather

On 2018-09-17 by (mod) - Does sewer gas come out of the house roof vent pipe?

Yes. Mike.

On 2018-09-16 14:52:27.020165 by Mike

Does sewer gas come out of the house roof vent pipe?

On 2018-05-08 by Anonymous - Does the a vent pipe need a slope to prevent freezing condensate?

Yes Ron

On 2018-05-08 05:04:01.211307 by Ron

It's not a roof leak. Roofer has been in attic twice trying see if there is a leak. He cannot find any staining on the sheathing.

The only spot he found wet was around vent pipe running across ceiling at a pipe joint in vent piping. He mentioned the slope seems wrong. Does the a vent pipe need a slope to prevent condensation in line staying in low spot in line, freezing over winter, then leaking from joint.

On 2018-05-07 by (mod) - condensate problems in plumbing vent?

Are we discussing a plumbing vent leak (perhaps condensate in the line leaks out in some conditions) or a roof leak?

A close inspection in the attic or roof cavity should make it pretty easy to distinguish among those: if there are water stains on the roof sheathing or framing above the vent pipe then it's a roof leak.

On 2018-05-06 by Ron

Leak in vent pipe running across ceiling. I had my roof replaced a few years ago, and I have a stain appear on my ceiling, water run down kitchen hanging light and sometimes the patio doors. This happens in spring when it warms up in the

Spring and snow melts from roof or has melted off and it starts warming up. The roofer has investigated leak, on the roof and in attic. The only thing he has found was some wetness around Venting pipe running across ceiling from kitchen sink. It felt damp around there and pipe. Roofer stated slant seems off and the a connector join was damp.

Could the vent pipe collect condensation over winter and freeze in pipe and then melt and leak through joint causing the leakage. Also I am away 3 months during winter and have heat turned down. Would that contribute to problem.

On 2018-04-24 by (mod) -

Possibly, Paula if the vent is specifically one intended to relieve the pumping chamber for your sewage pump

On 2018-04-19 by Paula

Can a clog vent pipe cause problems with sewage pump.

On 2018-02-28 04:43:56.871015 by (mod) -

Smell testing for plumbing vent connections would be unreliabke if you do not smell anything.

Listening at the vent for drain noise when a toilet is fkushe d msy help.

A plumber can send a camera through the line

On 2018-02-28 01:41:55.106424 by Sam Schaperow

How do I figure out if a vent pipe on my house, which has two vent pipes, is connected to the pipes? If it isn't, I'd like to be able to remove it. If it is, I should keep it. Can I test it by going on the roof and smelling it? Would that tell me if it is functional?

On 2018-01-18 14:52:43.246710 by (mod) -

Bob

Search this site using the search box above to find our diagnostic article on COLD WEATHER SEPTIC ODORS - perhaps a frost-clogged plumbing vent.

Note that a trap may still smell even if it's not leaking sewer gas, since a trap can accumulate sludge and bacterial growth.

On 2018-01-18 12:20:11.279192 by Bob

Going nuts trying to figure out how sewer gas is entering through 2 p-traps in our home. In cold weather only, especially when we're running the wood stove, and only when we're putting a lot of waste into the septic tank (showers especially). I visually checked the water level is the washing machine p-trap when the shower was being used, and it is not being drained. We hear no gurgling in any of the drains. The smell is NOT coming from any outside vents. It's coming from 2 p-traps -- but even after we put water in the traps, they still stink.

On 2018-01-17 21:08:28.910079 by (mod) -

Possibly but more likely the problem is a downdraft from the rooftop, or a sewer odor from another source such as a vent located near ground (found on some houses connected to sewers).

Start tracking down the trouble at PLUMBING SYSTEM ODORS - https://inspectapedia.com/septic/Sewer_Gas_Odors.php

On 2018-01-17 17:11:25.424993 by Anonymous

we can smell septic odors outdoors at times. Would it help to lengthen our roof vent pipes more than the 6" minimum?

On 2017-08-03 02:23:51.207915 by Carolyn

Experiencing sewage odor in downstairs bath room which was remodeled approx a year ago converted washer dryer hookup into a shower smells gets worse during rainy days but now always present plumber did camera inspection and did not find a problem also only started smelling odor after new roof and siding

On 2017-06-19 23:41:23.758602 by Kip

Random loud vibrating noises and temporarily stops when a toilet is flushed

On 2017-03-22 by (mod) - We cracked the sink pouring boiled water down it

Cleaning the sink drain is a nice starting point in dealing with odors in the off chance that something sticky and smelly is affixed in the trap or drain or (on bath sinks) overflow passage.

But

Watch out: pouring boiling water down a sink drain indeed can damage the sink or even some piping.

Besides, as I see you understand, if odors persist there's another source.

I take it you did install an auto vent under the sink, right? And that helped? Perhaps by reducing the load on the improper or too-distant original vent piping.

The remaining possibility is indeed that there's a cut, un-glued joint, opening in the vent system in or near the smelly sink.

I agree perfectly with your reasoning about the distinction between the time of onset of a smell and the time the building was built, and I agree that if the problem were simply an original construction error the smell ought to have always been present.

What's missing are a few possibilities that complicate that reasoning:

What else has changed in the building? Opening or closing a window or door, running or not running a fan, air conditioner, forced warm air heating system, all change how air moves in a building and some can create a negative pressure that changes how odors show up.

Also I wouldn't rule out the possibility that an original, existing vent line has developed a leak: on occasion I've found plastic vents that were jammed togeher in fittings without glue - no odors appeared for many years; finally, perhaps due to thermal movement or other disturbance, one of those connections opens up and the odor shows up.

In my OPINION a smoke test is not just smelly, but it's not entirely reliable. Do me a favor and report back what the plumber says about the utility of the smoke test if the leak in vent piping (or drain piping for that matter) is an enclosed building cavity such as wall or ceiling. Does the smoke show up then? How? Where?

SO ... also a lot of trouble but maybe ultimately necessary, might be a pressure test of the drain and vent system piping.

First I'd try to do some careful sniffing to see if you can get closer to the odor source.

On 2017-03-22 by Irene

we have a sewer gas odor coming from one sink. It has been there for years but has gotten worse. We notice it when we run the water. That seems to bring the smell up. The sink drains have been cleaned with everything you can imagine. The sink drains just fine.

We even cracked the sink pouring boiled water down it and had to replace it and the plumbing under it. There is a sink just directly on other side of the wall on the same vent system and if we plug up the offending sink the smell can come from that sink when you run water.

Roto Rooter came and used a camera from the roof vent and also from the sink. They said the vent was clear.

But the sink was not vented properly and suggested putting in an auto vent under the sink.

The smell is less but it is still there when we run water ($300 dollars later). They suggest a smoke test which is very expensive as a next step. The thing that puzzles us is that if this sink was vented wrong it seems we would have smelled this for the whole time we have lived here. I only remember smelling it in recent years and getting much worse. Any ideas or clues based on all this!

On 2017-02-20 1 by (mod) - insect nests can clog plumbing vent

Gases may not have killed bees or wasps in a plumbing vent.
It may be possible to snake the vent to push any obsctruction down to a larger diameter drain.

On 2017-02-20 21:42:12.904577 by Ab

@Ab,
CORRECTION 4 INCH PVC PIPE. sorry :)

Hi I have a question. We have a 3 inch wide PVC plumbing vent on the roof. We have pretty bad wasp issue during the warmer months (ongoing for a few years). I think a lot of their nests are concentrated at the corners of our rancher style home under the vinyl siding.

But we still have a ton fly around on the roof. We've been having a sewer gas smell coming from a 1 bathroom in the house. Do you think wasps could a made a nest in the plumbing vent on the roof. Ours you can't see straight down. There's a curve in the pipe.

So my thoughts were possibly the wasps made a nest just past the curve in the pipe. My husband thinks the gases would have killed the bees. I'm just wondering if anyone else had any thoughts. Thanks so much.

On 2016-08-23 22:02:54.874635 by (mod) -

Keep in mind that some of the most-competent plumbers may not be good communicators on the phone nor in writing.

What you describe sounds like a sewer line backup or sewer gas backup; if you smell sewer gas I'd ventilate the areas and avoid doing anything that makes a spark (switching lights on and off for example) as sewer gas, depending on the concentration in the home, can be explosive.

If you see this condition only at one fixture more likely there's a blocked local drain line.

Search InspectApedia.com for SEWER GAS to read details.

On 2016-08-23 21:33:50.828309 by christian

First off...I am hard of hearing. I am on the computer, nothing else is on in the house. I have the windows open, it is a really nice day. I hear this loud rumble. I go to look out the window...see nothing. I realize it is coming from my toilet. The noise stops, and the little bit of water left in the toilet, starts to bubble. And then, an odd smell. I called the plumber right away, and he says" don't worry"...I will be there tomorrow. Well...I am worried! He said "it's probably a gas valve" Can I really wait till tomorrow?????

On 2016-08-09 17:33:17.902726 by (mod) -

Air blowing down a plumbing vent can cause odor backdrafting in buildings, worse if the vent piping is leaky or broken or improperly terminated.

But running a microwave?

A pressure test would tell you if the vent system has a leak - though it's going to be more costly than running water through the vent system as openings have to be plugged.

A smoke test probably won't show a leak if the leak is in the vent where it passes through a building wall or ceiling cavithy.

On 2016-08-09 16:57:21.476058 by Linda

Yes, I believe that any air movement increases the odor. If so you suggested that it could be the plumbing vents. I have 2 on my roof. Should I try using a hose forcing water down the vent and see if there is a obstruction? If that doesn't reveal anything, would a pressure test be a safer and more accurate method.

On 2016-08-09 14:26:47.777747 by (mod) -

Linda,

If the odor is of sewage or sewer gas, sure a a plumbing vent problem could be a source of odors, but honestly I can't imagine how a microwave would be related
to a plumbing vent problem.

Perhaps the fan from your microwave is stirring air around that appliance and thus increasing an odor level?

Here is a simplified procedure: https://inspectapedia.com/odor_diagnosis/Odor_Diagnosis_Steps.php

Here is a diagnostic checklist: https://inspectapedia.com/odor_diagnosis/Odor_Diagnosis_Checklist.php

Looking at time relationships can also help.
This Odor Log might help https://inspectapedia.com/sickhouse/Odor_Log.pdf

On 2016-08-09 12:57:50.093055 by Linda

I have very strong odor throughout my house even when nothing is running. When there is any kind of air movement, such as a windy day, or a helicopter flies by, when I turn on my microwave, dishwasher or when the HAVC system is on the smell is much worse. I've replaced toilet rings,checked pea traps and snaked every pipe in the house. Nothing is draining slow or clogged. Could it be a venting problem? A plummer recommended a smoke test. I would rather exhaust all of the other possibilities before i resort to this expensive and maybe not inclusive test. I read on this site that a pressure test on the venting system would reveal a sewer gas leak. Would this be a better test then a smoke test to possibly reveal the problem. What else can I do to find the odor???

On 2017-08-25 by (mod) - approaches that can help sort out this toilet odor problem

Sue,

There are a couple of approaches that can help sort out this toilet odor problem.

One is to spend time in fresh air so that your sense of smell will be at its best, then enter the bathroom and sniff around the toilet base, sink trap, tub trap, etc to see if you can spot where odors are strongest.

Two is to flush the toilet and listen for clues that there is a venting problem like blocked or leaky or inadequate drain line venting. If on toilet flush a nearby sink gurgles then venting is not working.

Three, more involved is to have the drain system pressure-tested by a plumber who knows how to do that. The fact that smoke came out of a vent is not the same as a pressure test. Smoke shows that air passes up and out of the vents but doesn't tell us
if the vent is also seeping sewer gases into the building from leaks where the vent passes through the structure. So the technician's comments are incomplete.

at SEWAGE ODOR SOURCE LOCATION https://inspectapedia.com/odor_diagnosis/Sewer_Odors_Source_List.php I list a series of other causes of sewer gas smells that you should look-through. That article is part of a series of procedures on tracking down sewer gas smells.

Do keep me posted as what you learn will help others. - Mod

On 2017-08-25 by Sue - smoke test didn't find source of toilet odors in the vent system

Plumbing question I think--New construction home with unfinished full basement with odd smell appears to emanate from two toilets both on first floor. No smell in second floor bath nor laundry or kitchen. Had both toilets reset with new wax rings. No change.

Builder agreed to change out the toilets with identical but new ones replaced wax seals again. Flanges are level with floor. No change, odor still existed. Another plumber came and reinstalled toilets with new wax seals.

Master bath toilet on tile he caulked with 3 inch opening in back and smell is now lessened but still slightly noticeable. Powder room toilet smells just as awful as ever. Dropped bleach into toilet bowl, saran wrapped bowl, smell still there.

Had a smoke test done. No smoke in home or attic spaces(there are two). Have 5 vent stacks--kitchen, master bath had plenty of smoke coming out, roughed in basement toilet stack had nothing as expected, remaining two only one vent had smoke passing through to outside.

I am assuming one vent is for second floor bath, one for first floor powder room and laundry.

Technician stated since no smoke in house, even though no smoke exiting vent indicates no problem. It is possible the vent stack is non-utilized but since all other rooms appear to have their own vent I find it unusual that all three remaining rooms--powder, laundry and second-floor would be vented together. There is no gurgling noises when multiple systems are used.

Could there still be a vent problem, specifically the vent that was smokeless?

On 2017-07-14 by (mod) - Check air return opening to see if there is a sewer gas leak or a dry drain trap nearby

Wayne, Speculating,

Check each of the air return openings first to see if there is a sewer gas leak or a dry drain trap nearby, such as a basement floor drain near an air inlet on an air handler.

On 2017-07-14 by Wayne H.

If I flush a toilet or run the shower while my central air is running, I often (not every time) get a foul sewer smell throughout my home's duct work. I'm on public sewer. This has been going on for years.

On 2017-07-14 by (mod) - tree roots block drain line?

Thanks for the follow-up Jim R - that will assist other readers. Keep us posted. Let me know in particular what other sort of blockages are in the in-ground drains or piping; for example tree roots

On 2017-06-15 17:48:23.419788 by Jim R

Okay, the plumbing is up and running again and it appears the situation will be resolved for somewhere between $2-2,500. The drain people came out but felt the septic tank was likely the issues so they left. Septic tank was working fine but since it was open and not cleaned in 37 years, as far as I know, had it cleaned out.

The drain people followed up and water jetted and scoped the pipe. There was an accumulation where the drain pipe was damaged so they'll be sending someone out to deal with that next week.

Thanks for the response, I got to that diagnosis on my own after I posted. I went up on the roof and snaked the vent in case some critter or tree droppings had clogged the 3" vent and hit nothing that indicated any blockage.

I have a pro coming out in the next half hour and will post the ultimate resolution for anyone experiencing symptoms similar to mine. The ugly part is that I have no diagram of what the system looks like other than knowing it's a sand mound system that's 37 years old. The township was very rural back when it was built and they have no documentation to help me.

On 2017-06-13 by (mod) - main waste or septic problem shows up as bad drainage

Jim:

Your description makes me think the problem is in the main waste line or is a septic problem. We should be able to verify that by noting that running water anywhere in the building produces the sound.

Conversely if the sound occurs only when water is run in a specific location (kitchen) we'd guess that the blockage or vent problem is between that set of fixtrures and the rest of the drain system.

If it were my home I'd go ahead and have a plumber snake the line as a step that might repair a clog and that is also diagnostic - what sort of blockage is encountered? where was it in the piping system? If the snake goes freely to the tank we know that the next step, inspecting the septic tank, is likely to show us that the tank levels are abnormally high and the system is backing up.

On 2017-06-13 by Jim R gurgling in the hall bath at the back of the house

I have an issue that developed very recently. I was running the dishwasher in the front of the house and was in the bathroom and I heard gurgling in the hall bath at the back of the house. The drains run from the back to the front.

There is a large (maybe 3") vent through the roof in the back that services the two bathrooms and the washing machine plumbing and a second vent that runs up near the kitchen for venting that area. Last year I had an issue with the kitchen not draining and after some trouble shooting, I found that the vent near the kitchen was blocked with something. Snaking the vent pushed whatever was in there.

So yesterday my gf heard the same gurgling when she ran water in the bathroom sink. I had been working in the garage and had some things to move to the basement. When I got down there, the floor around the hall toilet drain was flooded and I could see water coming out from the area of the drain and getting on everything. I realized I had run a load of wash to clean some garage rags earlier.

I put a galvanized container beneath the pipe a few minutes ago to catch most of the water if it ran out and put a load of dishes in the dishwasher to see if that would run out or drain normally. Well, the water backed up to the toilet in the back of the house.

Would a clog in that rear vent create a backup from water down the line to the kitchen or, as I fear, am I dealing with an issue with the main out to the septic system?

On 2017-05-23 by (mod) - how to stop wind problems and downdrafts at plumbing vents

I'd look for a vent top wind screen or cap - there are models that look like a 90 and that rotate to face the elbow's back into the wind. If you can't find one let me know and I'll dig up some product examples.

On 2017-05-22 by bnovotny52@gmail.com - sloshing in toilets

I live in a very windy part of the country. When the wind howls we get extreme sloshing in the toilet and a sewer smell in some of the sinks.

The roof vent is up to code. It would seem that we are
getting a back draft. When the days are calm there is no problem. I have seen P-traps or 90's added to the vent. Would this help?

On 2016-12-18 by (mod) - low water in the toilet bowl

Carolina,

Your home could have a vent clogging from frost but low water in the toilet bowl suggests that the flush or fill valve needs adjustment

Use the search box just above to search inspectapedia.com for GURGLING DRAIN NOUSES to see diagnosis and repair information

On 2016-12-13 by Carolina

We just recently began seeing a very low water level in the toilet that fluctuate with the heavy winds. We also notice gurgling in the bathroom sink. We've lived in our home over ten years and this is happening just in the last month. Could it be clogged vent stacks and if so, how are they checked and cleared?

by the way, thank you so much for this web page. My husband is a disabled vet and we don't have the money for plumbers. He's pretty good at this sort of thing but this one has him wondering. Thanks again! (also there is no odor)

On 2016-07-31 by (mod) - wind carries sewage odors

Andrew McGibbon said:
In the event where you are smelling the odor coming from vent stacks outside the house, as explained above, this can be the result of wind vortexes that carry the smell down and around the house. This can be caused when a house is situated against a hill or line of trees.

The wind carries the odor down from the septic vent on your roof or yard vent instead of carrying it away. One solution, as indicated above, is to raise the height of the pipe. Another is a septic vent filter.

Question: what is "short stack" plumbing ventilation?

short stack ventilation? - John

Reply:

John if you are referring to plumbing vents that are too short, we discuss that in the article above. I'm unsure what else you're asking. If a plumbing vent stack is too short a risk is that in climates where there is snow cover, under heavy snow conditions the vent may become blocked.

Question: unused plumbing drain now seems to be clogged

after noticing a standing water in a newly installed vanity - the drain hasn't been used for long time - I tried to used water pressure to dislodge any obstacle there. Instead I got a leak around the vent in the ceiling of the adjacent closet. Any comments? Thanks. - Ad

Reply:

Reader comment: It sounds like your blockage is downstream and by using water pressure, you are pushing the water upstream toward the vent. There should not be any water in the vent pipe. - reader B

Question: faint sewer odors come and go in several areas of our house, worse towards septic tank

We notice faint odors that come and go in a couple of areas in our house. they happen to be closest to the end of the house where our septic tank is located. One distinct location is a bathroom where a toilet had previously been lifted by a plumber to remove a flushed toy and I am now suspicious that this wasn't sealed properly when replaced (how do I know if this is the case?).

The other is an adjacent bathroom where a shower drain seems to smell despite regular addition of water - also notable is that this bathroom had a very pungent gas odor when the septic tank was pumped. Is it normal for odors to come back into the house during pumping? (or does this suggest a malfunction of the shower trap or possibly a ventilation leak?)

A plumber has suggested that the vent stack for this bathroom has been placed improperly on our flat roof, too close to a parapet (actually only 2 to 3 inches away)& that we are probably having downdrafts into the ventilation pipe (although I am not sure how this could explain the substantial flow of odor into that bathroom during pumping). The last area is in our garage where there is a utility sink & this also had a horrendous odor during the pump out.

Oddly, these 3 problematic areas are in very close proximity to each other at one end of our ranch style house and I am not sure if there is a common problem between them or multiple separate problems. I have had it looked at by septic companies and plumbers and have not really gotten a solution. How do I find someone that can solve this mystery? - Arizona

Reply: use a smell patch test or a person with good sense of smell to track down strongest odor source, check toilet wax ring

Arizona

I'd try a simple sniff test to see if you can track down the strongest odor source. It's not a big job to pull a toilet and replace a doubtful wax ring if that seems to be the trouble area.

Sometimes drains smell even if not blocked, and even if the vent system is working - due to accumulation of hair, sludge, and bacteria in the drain trap. You might try cleaning that smelly shower drain.

It's worth considering with care your observation about the near-location of all of the smell-suspect fixtures. See if you can determine that all of them share the same drain or vent pipe.

Finally, your plumber's suspicion is worth considering, but you might be able to sort that theory out by taking note of the history of the smell problem. If the problems are long-standing and relate to weather/wind, a vent problem could be more suspect.

Question: long horizontal plumbing vent runs can leak into ceilings below

One potential issue that was not mentioned in the article:
I have a horizontal vent run of ABS in my attic, approximately 20 feet long. I'm assuming multiple vent stacks are being joined. I recently had a water leak from the horizontal pipe section onto the 2nd floor ceiling. Upon inspection I found that the horizontal run had a split along the side of the pipe. It appears that rain water had been collecting in the horizontal section and must have frozen, splitting the pipe.

I cut-out and replaced the split section, but it appears that I need to modify the horizontal run so it has some slope on it to allow the rain water to drain out. Just an FYI for folks out there. - Mike T

Reply:

Thanks Mike. - DF

Question: sulphur smell in closet adjacent to a toilet/bathroom

We have an issue with a sulfur smell in a closet on the second floor of our home. The closet shares a wall with the toilet in the bathroom.

The bathroom and toilet do not smell, but there is a strong sulfur smell in the closet that comes and goes -

it seems to be stronger on sunny days. There is also a window in the closet and a soffit vent right outside of the window.

We had the plumber come out. He said he checked the vents in the attic and they were connected properly? Any ideas? Thanks!

Reply:

Sulfur smells that seem to relate to a septic system or plumbing drains are often traced to a loose toilet, missing or leaky toilet wax ring, dry plumbing traps at unused fixtures, inadequate plumbing vent piping by location or routing, or on occasion, a loose leaky connection in the plumbing vent piping as it runs concealed through building walls, floors, or ceilings

If checking the easy accessible problems like toilet wax rings and dry plumbing traps doesn't solve the problem, and if you believe the plumber's view that all of the drains have adequately located and sized plumbing vent piping, then next might be a pressure test of the vent system to see if you can prove that it is leaking.

Question: when toilets are flushed sewage comes up in the bath tub, and toilets over-fill

I have 2 toilets that when flushed drain into the bathtub. I have a septic tank that has been checked and is working ok, Per the repair guy. We have had 3 separate plumbers come out and no one has been able to fix the problem. Toilets overfill with water by themselves, and when running anything like a dishwasher or Washing Machine everything overflows into the tub.... any suggestions?? I'm dying here.. - Shaun

Reply:

Shaun I read more than one problem here:

1. your toilets over-fill: if you mean that the toilet tank becomes too full, that's not a drain waste vent problem, it is a toilet fill or flush valve control problem; if you mean that the volume of water in the toilet tank is normal (fills to the "fill line" marked in the tank) but the toilet bowl becomes too full when the toilet is flushed then

1.a. the toilet drain is clogged somewhere in its routing

1. b. the toilet drain is not properly vented and the result is slow draining

2. the toilet flush water volume and delivery rate is improper - check the flush valve

The observation that the toilets overfill and that "everything overflows (presumably backs up into) the bathtub when a dishwasher or clothes washer is running is a very strong indicator that you have a blocked or partially blocked drain. Sometimes the blockage can be pretty far downstream from the toilet(s) or even from the building itself.

A clue that suggests that condition is that when no water has been run for 4 hours or more, you get a few good toilet flushes before things begin to back up (you're filling up the drain piping with wastewater).

If the toilets back up immediately, any time, regardless of how long since any water was run into the drain system, then the blockage is probably closer to the fixtures.

Question: toilet drains slowly - a 20 ft drain auger doesn't fix it, other toilets drain OK

I have one toilet that has been draining slowly, I have used a 20 ft plumbers auger and it is still draining slower than normal..the other toilet drains perfectly...? - Frank Mann 1/18/12

Reply:

Frank, your question suggests that either your snake passed right by a partial drain blockage, the toilet is not adequately vented, or the blockage is further downstream in the piping but ahead of other toilets that are draining OK.

Question: double sink drains slowly

I have a double sink that was installed as part a renovation. When water drains in one sink, you hear a glub, glub, ..... coming form the other drain. I suspect the new installation was not vented properly. How can a positively identify the source of this annoying problem - Scott 3/19/12

Reply:

Scott I would start by removing, cleaning, and inspecting the drain traps below the two sinks; also, if the sink is not properly vented, it would be common for the draining sink to draw air in to the drain pipe system through the adjoining sink drain opening and trap.

Question: black specs on bathroom sink keep returning

Two sinks in separate bathrooms have black specs around the sink bowl drain. If I clean them with bleach, or Comet within short order they come right back. I suspect it is coming out of the drains as the black gradates from darker around the drain to lighter a couple of inches out. The problem seems to increase in warmer weather. I am thinking mold, but the cause? I have tried dumping drain cleaner down the drain. I have also tried bleach at different times and it's a no go. Help me! - Tim 3/24/12

Reply:

Tim I am doubtful that black specs on a sink are being caused by gases coming out of the drain, more likely there is a stain source in the water supply or plumbing system.

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