Plastic and cast iron drain piping (C) Daniel Friedman Plumbing Drain Noise Repair Methods

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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.

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.

How to repair problems causing plumbing drain sounds

Snow on plumbing vent - ok (C) 2013 Daniel FriedmanJust 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

Article Contents

2 Types of Plumbing System Noise Sources

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.

  1. Plumbing defect noises associated with plumbing system problems or defects whose identification and diagnosis is discussed at PLUMBING DRAIN NOISE DIAGNOSIS z

    and right here at PLUMBING DRAIN NOISE REPAIR.

    Our complete list of various plumbing system noises is
  2. Plumbing drain/waste/vent noises that occur normally during plumbing operation, such as the sound of wastewater rushing through a copper main building drain, perhaps overhead in a basement family room, are cured by adding insulation in strategic locations or where cost-justified, by changing the type of plumbing materials (copper changed to cast-iron or example).

    Information about controlling plumbing noises in buildings by isolating sounds, stopping noise transmission, or adding sound insulation is at SOUND CONTROL for PLUMBING

    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.

Photograph of a house with missing plumbing ventsHow to Stop Plumbing Noises by Adding Missing plumbing vents

Add missing plumbing vents to stop gurgling & slow drains

The photo shows a large house with only one plumbing vent visible (click the image for a larger view).

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 investigating further.

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.


Photo of a vacuum breaker plumbing vent installed in a Poughkeepsie Attic (C) 2013 InspectApedia Barry Lam, Daniel Friedman

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.

Install vacuum breaker plumbing vents (e.g. V-200™) where routing a new vent line is troublesome

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.


Stop Plumbing Drain Noises by Adding Sound Insulation

Foam insulation in plumbing pipe chase (C) D Friedman Eric Galow 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:

What to do now to reduce drain pipe noise?

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.

Photograph of a plumbing vent blocked by a visiting frogBut 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.

Stop Gurgling Drains by Clearing Blocked Plumbing Vents

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.


How to repair frost-blocked or snow-covered plumbing vents

Snow on plumbing vent - ok (C) 2013 Daniel Friedman

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.

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.

Stop Plumbing Noise by Curing Sluggish or Blocked Plumbing Drains

Clogged drain traced to flushed underpants (C) Daniel Friedman Brian GilliganOften 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 CLOG REPAIR, UN-BLOCK. But first you should read the text below.

Also see SEPTIC BACKUP PREVENTION (private septic systems)

or see SEWER BACKUP PREVENTION (buildings connected to municipal sewers) and also see the health and safety concerns discussed


Gurgling drains may indicate a partially blocked drain line or sluggish septic system

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.


Odors due to clogged plumbing vents, drains, or blocked, failing 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 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 DRAIN & SEWER PIPING - home


Or see these

Plumbing Noise Articles

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PLUMBING DRAIN NOISE REPAIR at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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