Plumbing Drain Noises
Diagnosis & repair of glub-glub, burbling, and other drain sounds
PLUMBING DRAIN NOISE DIAGNOSIS - CONTENTS: How to diagnose & fix plumbing drain noises - plumbing drain sounds may explain drain problems. What causes noisy plumbing drains? How to investigate & repair plumbing drain sounds. Add sound insulation to reduce plumbing drain noise transmission in homes.
Drain noise complaints due to a V200 anti-siphon valve
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Plumbing drain noise diagnosis: this article discusses how to identify different types of plumbing drain sounds, including the cause, diagnosis, and cure of different sorts of plumbing drain noises - how to find, identify, and diagnose the source of plumbing drain, waste, and vent piping and plumbing fixture sounds.
We discuss how to add sound deadening insulation around new work or into existing plumbing pipe routes in buildings.
That "blub blub" or "glug glug" noise you hear from a building drain might mean that there is a problem with the drain system itself, such as a partial drain blockage, a drain venting problem, a drain odor problem, or even a failing septic system. This article 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.
Inadequate or missing plumbing vents & noisy, gurgling, or slow plumbing drains
If a gurgling sound
is heard at a sink or shower drain only when a nearby toilet is flushed,
or at a sink or shower when a nearby tub is draining, we'd suspect that the building drain-vent
system is inadequate.
This photograph shows a multiple-trap drain on a building sink - forming a double "S-trap"
which lacks venting and also is very prone to clogging.
In addition to watching for
eccentric home-made plumbing traps like this pair that are likely to cause bad
sink, shower, or tub drainage, check for the following:
Plumbing fixtures installed with no vent connection at all, such as a bathroom or kitchen
sink that use an "S" shaped plumbing trap.
Vacuum breakers at drains: Plumbing fixtures originally installed with no vent connection to which a (sometimes
permitted) local plumbing vent/vacuum breaker (such as a "V-200 plumbing vent) usually installed
right under the sink to permit air to enter the plumbing drain line as needed but
intended to keep sewer gases from exiting that same drain - a one-way valve. If the
valve is defective or "stuck", inadequate, or improperly installed this problem may occur.
Plumbing fixtures that are installed too distant (perhaps more than 5') from the
vertical plumbing stack vent that is supposed to serve them.
Island sink vents: special case of this plumbing
venting problem can occur at island sinks installed in kitchens. Special drain vent piping
details are required to assure that such isolated fixtures will drain properly.
See ISLAND SINK PLUMBING VENTS
Plumbing fixtures whose vent diameter is too small in the building or above the roof line - resulting in frost clogging in freezing climates
Plumbing fixtures whose vent line in an attic was not extended to outside the building (lead
to indoor odors and potentially dangerous, explosive methane gas accumulation.
Blocked plumbing venting & gurgling or slow plumbing drains
A plumbing drain line could itself blocked, as opposed to a blocked or inadequate
plumbing vent line. In the case of a partially blocked plumbing drain, case all of the fixtures
served by that drain line will always be slow to drain.
When weather and safe access permit going onto a roof (or using the services of
a professional for that purpose), check for blocked building plumbing vents such as plumbing vents that
may have become blocked by an insect nest, birds nest, or as shown in this photo, a frog.
In freezing climates, check in winter to be sure that the plumbing vents are not being
blocked by frost or by snow-cover.
Gurgling drains may indicate a partially blocked or sluggish sewer piping or or blockages in the private septic system
the outside sewer line is partially blocked, or if waste piping to a septic tank or
from a septic tank to a drainfield is partially blocked, the building drains may appear to
work normally until there is a surge of usage such as an increase in occupants or when using
a washing machine.
In lighter usage the waste and wastewater flow down into the main drain
line or sewer line where they are in effect, "stored" while the waste slowly seeps past
the partial blockage. As wastewater seeps past the partial main drain blockage a
gurgling sound may be produced at fixtures in the building as air is drawn intermittently
into the drains - an effect more pronounced if the building drain vent system is inadequate.
In heavier usage of building fixtures, such as when there are many occupants or when doing
laundry, the additional volume of water may first cause this "gurgling drain" symptom to be
more pronounced, and as the blockage worsens, the building drains may actually back up during
heavy use. This condition can also produce sewage smells or sewer gas backups into a building.
Gurgling drains heard indoors may also be caused by a clogged septic filter, as reader Will pointed out (at SEPTIC FILTER CLOGGING SIGNS 2017/01/14), or by clogging anywhere that blocks sewage into or out of a septic tank.
At the end of this article we list further diagnostic advice for plumbing noise diagnosis & repair, curing
blocked drains, diagnosing blocked septic systems, or detecting inadequate plumbing vent systems.
Sounds of running or dripping water in a building drain
Continuous Plumbing Drain Sounds like Trickling Water or Water Dripping Noises
Trickling water sounds coming from a building drain or fixture might indicate a
fixture leak problem. A sound of dripping heard inside a drain line, or the sound of continuous running
water may be heard.
Both of these can indicate that a plumbing fixture in the building has
a water supply leak which is leaking into the fixture. If the drip and sound
are occurring outside of the fixture or its drain, such leaks are usually discovered
pretty quickly when water or leak stains appear in the building.
But a plumbing leak that causes a
toilet to run, the only clues might be noticing that the toilet fill valve is sometimes
re-filling the tank even though no one has used the toilet, or one might hear water running
in the building drains, or if the property is served by a private septic system, the
system may experience flooding and backups.
Hearing the sound of running water in a building drain is not likely to indicate a
problem with the drain system itself.
In older buildings where cast iron and steel drain pipes were used, not much
sound normally is heard: even the sound
of running water, say when a shower is running or when a toilet was flushed.
But in a more modern structure that uses plastic or copper drain piping these
materials can transmit the sound of running water to the building interior.
Builders can reduce sound transmission from plumbing lines by enclosing them
in insulated chaseways.
We have also found cases in pipes in a building transmit sounds from one area
of the building to another. We've also found that electromagnetic fields generated
in a building, say by a bank of electric meters located in one area, can be
transmitted to other building areas through metal piping.
Normal (but annoying) plumbing system noises that will be corrected by noise transmission control or sound insulation are discussed
at SOUND CONTROL for PLUMBING, a section of SOUND CONTROL in buildings where we describe controlling the transmission of plumbing noises in buildings.
How to find the source of plumbing drain sounds
An experienced plumber can often diagnose these problems quite quickly since s/he is more
familiar with plumbing problems than most homeowners. But if you want to do some drain sound
detective work yourself here are some steps that might help.
Identify the fixture: Identify which fixtures are producing the sound: is it all fixtures in the building? If so we
suspect a system drain problem or that the building has only a single inadequate vent system
or no venting at all. If the sound occurs only at a specific fixture, we suspect a blockage
or vent problem local to that bath, kitchen, or laundry area and its vent or drain piping.
Flush the toilets: Blocked or inadequate vents can produce slow drains as well as noise. But if none of the
drains are slow, but you hear gurgling at a nearby sink when the toilet is flushed, take a look
underneath the sink. If the trap is shaped like an "S" over on its side, the sink is probably
not vented and the flushing toilet is trying to draw air into the drain line from the
nearby sink when the toilet is flushed.
If the trap is shaped like a "P" over on its side, with
its horizontal outlet running into the wall, we can't see if the sink is really vented or not,
but the style of plumbing is more modern and it might be vented. If the trap is some crazy
combination of multiple bends and parts, call a professional plumber to unsnarl the installation
since such jury-rigged plumbing traps are likely to be problematic.
Look for other appliances or systems that are sending water or waste into the building drains: dishwasher or clothes washer cycling, even a heat pump or air conditioner condensate pump cycling to send water into the drain system may make periodic drain noises.
Look in the attic for a plumbing drain line that passes vertically up from the floors
below and out through the roof. If you can't find one, the building may not have proper
Look outside for plumbing vent pipes poking up through the roof in one or more areas.
If you see a plumbing vent at one far end of the building where baths are located, but no
plumbing vent stack pipe over the end of the building where a kitchen or laundry are located,
those rooms may have been built without proper plumbing venting.
Check the plumbing venting system - A blocked plumbing vent can cause poor drainage and gurgling sounds at drains;
See PLUMBING VENT NOISE
Check out the septic system (or main sewer line connection): for signs of backup, blockage, or odors outside.
Effluent breaking out to the surface, muddy or soggy areas, smelly areas, may indicate that
the septic system, or part of it, are failing and are periodically not accepting waste. Check the private septic system (if your building uses one) - for blockages in the line from building to to septic tank, for solids blocking the septic tank inlet or outlet, or for a clogged septic tank filter (SEPTIC FILTER CLOGGING SIGNS) or for a clogged or blocked drainfield piping.
Call a plumber to investigate further by visual inspection, drain pressure tests, or using a drain camera or scope
Reader Question: What can we do about the loud noises coming from the plumbing drains in our home?
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. Kathy in Calgary
[Our photo, left, shows ABS drain/waste/vent piping (DWV Piping) in a ceiling pipe chase in a New York home during a recent building addition project, courtesy of Galow Homes.
Reply: explanation of plumbing drain noise transmission and suggestions for adding sound insulation
Kathy, I am guessing that your home is fairly new and that the drain piping is ABS plastic (or PVC plastic) run in walls or pipe chases that at least in part pass through building interior walls or ceilings. Those pipes are indeed noisy and the noise is easily transmitted to the room interiors. By contrast, older buildings that used cast iron drain piping find there is less noise transmitted by wastewater running through the drains.
The level of noise transmitted is a combination of the acoustic transmission properties of the thinner walled plastic piping, the proximity of the piping to occupied space, the absence of noise insulation around the pipes, and details of exactly how the pipe was routed and supported.
Specifically, pipes that are in solid contact with building framing or drywall transmit more noise. Pipes that were suspended using acoustic-isolating hangers transmit less noise to the building interior.
As we cite
at PLUMBING NOISE CHECKLIST,
According to the Canadian CNRC, "Noise reductions up to about 15 dBA can be obtained relative to systems where no resilient mounts are used for pipes."
What to do now to reduce drain pipe noise?
Because it would be costly to tear out ceilings and walls to mess with pipe supports and routing, I'd seriously consider blown-in insulation into the areas where these pipes are routed. Typically you'd fill the ceiling joist or wall stud bay where the pipe is contained - fill it completely, a step that significantly reduces noise transmission.
Our photo (left) shows what the ceiling pipe chase (and surrounding areas) looked like after a professional blown-in foam insulation job in the same New York home. Subsequently of course drywall was installed over these surfaces (we do not leave foam insulation exposed because of fire hazards).
After this foam was installed there was no plumbing noise detected in this area when the toilet was flushed in the floor above.
Use foam insulation because it will flow around the piping into odd-shaped spaces and will fill the pipe space completely. Don't worry, your foam won't have to fill an entire wall or ceiling space, just the space where the pipes actually run, typically 16" or 24" wide by the length of ceiling section or height of wall section by the typical joist or stud width, say 10" or less for 2x10 ceiling joists, and 5 1/2" for 2x6 wall studs or 3.5" for 2x4 wall studs.
Nevertheless the volume of these spaces is more than you can fill consistently, adequately, and economically in a do-it-yourself project using little spray cans of foam purchased at a building supplier. So I recommend hiring a foam insulation installer.
Of course your foam installer should not have to tear off drywall nor foam as extensively as I show in our plumbing chase foam insulation photos above.
Rather it will probably be quite possible to fill the appropriate pipe routing cavities with foam by injecting foam through very small openings spaced along the route of the piping. The result will be no more than occasional 1/2" diameter or less holes to patch and paint along the pipe route.
Install Missing plumbing vents to eliminate odors, sewer gas explosion risks & unsanitary conditions
Adding missing plumbing vents::
The photo shows a large house with only one plumbing vent visible (click the image for a
We didn't see vents over or anywhere near the portion of the home which
houses a kitchen and bath. While it might be possible for the building to have a working
vent system, the combination of its age and other details raised a question worth
If we find that there are other "short" plumbing vents which
were covered by the deep snow in this photo, they need to be extended.
When plumbing vents are simply not provided, the proper repair is to install missing vent piping, up through
the building and through its roof.
In old buildings you may see vertical plumbing lines that were
added, in plain view, inside the living space. But modern construction "hides" these pipes in
the building walls. If you want to install modern, hidden plumbing vents, and providing your
plumber has shown you that in fact they're missing, you may want to wait until other more extensive
interior remodeling are in the works.
Vacuum breaker plumbing vents - V-200™: Meanwhile the plumber may install an illegal vacuum breaker
to improve drainage - these products can be added wherever a drain is having trouble getting enough
air to flow properly, but in most jurisdictions their use is subject to approval by the local plumbing inspector.
Repair frost-blocked plumbing vents
Fixing a freezing plumbing vent line in which the plumbing vent becomes partially or fully blocked by
frost or ice where it extends above the roof in a freezing climate, probably requires the
installation of a larger diameter vent from the attic out through the roof.
First check for leaks: before installing a larger diameter plumbing vent line, make sure that there is not
a hot water leak into the plumbing drains or continuous shower use. A water leak into the drain system can result in
continuous movement of water vapor or "steam" upwards in the vent system too.
In freezing weather
that water vapor may condense and then freeze in the outdoor portion of the plumbing vent system
simply because it's passing that way continuously.
Too-short plumbing vent stacks: A plumbing vent stack which is too short above the building roof can be blocked
by snow and then stop venting. But that does not mean that we should be installing
very tall (3' to 6') plumbing vents. Except in areas of unusual snow depth
such heights are probably much higher than needed.
The plumbing vent stack above a roof needs to be high enough to never be covered by snow, not more.
I speculate (really am guessing) that perhaps if a vent is TOO tall in a cold climate, moist air never will escape
at its top because the added cold length of pipe actually encourages freezing.
Stop Sewer Gas or "Sulphur Smell" Odors Caused by clogged plumbing vents, drains, or septic systems
Clogged, partly clogged, slow drains or a partly-blocked, failing drainfield can also cause odors when
the surge of water from the washer causes a gas backup in the system:
see Diagnosing Clogged Drains for more detailed
advice along that problem path.
Watch out: sewer gases contain methane and can cause destructive, even fatal explosions in buildings.
Septic additives like Rid-x won't fix a problem with building vents nor sewer odors,
and are generally not recommended anyway - see
Additives & Chemicals
for septic system maintenance. Are septic products needed? Are septic treatments legal?
Continue reading at PLUMBING DRAIN NOISE REPAIR or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Question: noise in shower pipes when air conditioner drains into sump pump
(June 24, 2015) Kim said:
I had a new air conditioner and sump pump installed last year before I could use my air conditioner. Now this year the condensation pipe runs to the sump pump but when it comes on to drain the water the pipes in the shower makes a noise sometime. Is that normal
I might say "normal" if we mean "common" but that's not necessarily OK. I'm not sure what you're hearing. If you hear water dripping into a trap that may be fine. If you hear gurgling drains then there's a problem with a drain blockage or with inadequate drain venting.
Question: noise in pipes when we flush the toilet
(Nov 3, 2015) david said:
when we flush our toilets there is a drain noises coming form the cilling
David, in the More Reading section above these articles ought to help out:
Continue reading at PLUMBING DRAIN NOISE REPAIRor select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Or see PLUMBING DRAIN NOISE DIAGNOSTIC FAQs
Or see PLUMBING NOISE CHECKLIST our complete list of various plumbing system noises
Question: Humming sound while water is running
(Nov 9, 2015) Vic said:
I have a two story house. When I flush the toilette or run the kitchen water, I hear a humming sound that last the whole time the water is running, but when I use the water up stairs I don't hear any sound. What could it be?
I don't know; if you have a private well I suspect well or pump noise transmission, say of a vibrating pump motor or loosely-mounted waer pipes.
If you're on municipal water I'd be looking for a valve that's obstructing the water and affecting the velocity just to create a noise to annoy you. Try slightly closing a supply valve.
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Developments in Noise Control, NRCC, National Research Council, Canada, suggestions for noise control, sound transmission through block walls, plumbing noise control, noise leaks, and sound control advice. Web search 01/17/2011, original source: https://www.nrc-cnrc.gc.ca/eng/ibp/irc/bsi/90-noise-control.html
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