InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
How to diagnose, track down & fix plumbing drain noise problems.
This article explains how to cure or get rid of annoying plumbing drain noises in buildings. We explain that one first needs to understand the type of drain noises - some indicate plumbing problems to fix. Where drains operate normally but are noisy, we discuss adding sound deadening insulation.
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 the cures for plumbing drain noises, and we refer to key companion articles that assist in that diagnosis.
Just a bit of snow sitting atop the plumbing vent that extends above the snow level on the roof (photo at left) is probably not a problem - heat from escaping vent gases should melt through a bit of snow.
But as we illustrate and explain below, in very cold weather moisture can freeze inside and block the plumbing vent above the roof line - just one of many possible sources of blocked plumbing vents and plumbing drain noises.
This article is about curing plumbing drain noises. If you need to figure out where a plumbing drain noise is originating, see this companion article: PLUMBING DRAIN NOISE DIAGNOSIS
First, it is helpful to divide cures for plumbing drain, waste, vent piping sounds and plumbing fixture sounds into two groups, because the actions we will take are distinctly different in each.
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.
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.
At PLUMBING DRAIN VENTS we explain the basics of proper plumbing vent piping and how plumbing vent piping errors cause trap siphonage, odors, and noises.
at NOISE, PLUMBING DRAIN DIAGNOSIS we include a question and answer case (with photos) discussing loud plumbing drain noises in a home along with our recommendations. Excerpts are below:
The level of plumbing drain noise transmitted into a space where you actually hear it in the building depends on these factors:
In new construction we can avoid noisy drains by using sound-isolating pipe hangers, attention to pipe routing details to keep pipes from having solid contact on ceiling joists and wall studs, and by providing insulation around the piping between ceiling joists, floor joists, or wall studs.
But in an existing building it would be costly and probably unnecessary to tear out ceilings and walls to correct these details. Instead we add pumped-in or blown-in foam insulation into the areas where these pipes are routed.
You could use blown-in cellulose or fiberglass but it's a bit more difficult to assure that those insulating materials will flow around the pipes in the building cavity. Instead we recommend filling the ceiling joist or wall stud bay where the pipe is contained - fill it completely, a step that significantly reduces noise transmission.
Our photo (above left, courtesy Galow Homes) 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.
As it expands, foam insulation will flow around the piping into odd-shaped spaces and will fill the pipe chase spaces completely. The "blown in" foam insulation won't have to fill an entire wall or ceiling space, just the space where the pipes actually run.
But because the volume of these spaces is more than you can fill economically using little spray cans of foam, we recommend hiring a foam insulation contractor to do this job. The foam installer should not have to tear off drywall to do this job.
Typically the contractor will fill the appropriate pipe routing cavities by injecting insulating 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.
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.
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.
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.
We 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.
Often slow or noisy plumbing drains are traced to a partial blockage such as the problem caused when our grandson Chase flushed his underpants down the toilet. We discuss this event and its diagnosis and repair
at TOILET CLOGGED. But first you should read the text below.
Also see SEPTIC BACKUP PREVENTION (private septic systems)
If 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.
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 CLOGGED DRAIN DIAGNOSIS & REPAIR for more detailed advice along that problem path.
Septic additives like Rid-x won't fix a problem with building vents nor sewer odors,
and are generally not recommended anyway -
see SEPTIC ADDITIVES & CHEMICALSfor septic system maintenance. Are septic products needed? Are septic treatments legal?
See these odor diagnosis articles:
Other advice about identifying plumbing noises is at PLUMBING NOISE CHECKLIST and information about controlling plumbing noises in buildings is at SOUND CONTROL for PLUMBING or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Continue reading at PLUMBING DRAIN NOISE DIAGNOSIS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Or see BLOCKED DRAIN REPAIR METHODS
Or see CLEANOUTS, PLUMBING DRAIN
Or see CLOGGED DRAIN DIAGNOSIS & REPAIR - home
Or see DRAIN & SEWER PIPING - home
Or see PLUMBING SYSTEM NOISE DIAGNOSIS & CURE - home
Or see these
Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia
Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia
Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
(Oct 22, 2012) stan said:
when flushing the toilet the bathtub makes some sounds?
Look for a clogged or partly clogged drain or vent line.
(Mar 5, 2013) rob k said:
When running dishwasher, kitchen sink and bathroom sink gurgle, (both on same floor). any suggestions? Thankyou in advance, rob.
Probably there is a shared drain and trap with the dishwasher - this noise may be normal.
(Mar 14, 2015) Karl said:
I have a problem with a dripping noise in the bathroom drain, when the cold water is running and draining out there is no noise, when the hot water drains the is a dripping noise, is it possible that it's just the expansion of the drain pipe rubbing against the studs? Thanks
Kudos for thinking up a possibility I've never considered. I don't think thermal expansion would make a dripping noise, more likely a squeak.
But a very small defect might leak under thermal expansion.
(Mar 21, 2015) NEIL said:
I hear a banging noise when the toilet is filling after a flush.
Questions & answers or comments about curing plumbing drain noises in buildings
Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website