Spiral spun steel galvanized iron water supplhy pipes in an older building - a possible location for pipe vibration or of whistling or shrieking water pipe noise © Daniel Friedman Building water supply pipe whistling or shrieking noise causes & cures

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Building water supply pipe noise diagnosis & cure: whistling, shrieking water pipe noises can drive you mad. Here we discuss the causes of water supply piping noises such as whistles or shrieks, we cite pipe noise research, and we explain how these whistling pipe noises can be cured or prevented in the first place.

Other types of building pipe noises both in the supply system (such as water hammer or pipe vibration) and in the plumbing drain system (such as gurgling drains) are discussed in companion articles linked to at More Reading at the end of this article.

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Water Pipe Whistle or Shriek Diagnosis

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

Since this past fall, I started to get a whistle in the pipes. I Have tried to look it up and get never the same answer. I just saw that could have been turning the outside faucets off could have caused backed up the air in pipes.

I am not sure what to do, as I am selling my house and I don't want someone to turn them on and hear that and be turned off.

A couple people have said [that I should] turn all the water faucets on at once for 5 minutes, as that would work.

I just want a professional, easy solution, because I can't hear [the pipe whistling sound] when the outside hose front or back of the town house are on. Nor do I hear the pipes shrieking when the bath room basin, bathtub, clothes washer are in use, nor when you flush toilets.

[The sound is heard at] the kitchen sink. The pipe whistle sound is not so bad there but then when we go to the second floor of the townhouse, that's when the tub and sink in there [make a whistling sound when in use]. [The water pipe whistling noise becomes much louder ] when the shower is on

Reply: here's where we start diagnosing whistling pipes

Water supply piping noise complaints are usually related to the pressure and flow velocity of water in the piping system. Because water pipe noises tend to be greater at higher pressures or velocities, often we can immediately stop the noise by adjusting water pressure OR water flow rate.

At PLUMBING NOISE CHECKLIST we note that plumbing noises that produce high-pitched hissing or whistling sound may be heard as water runs through building supply piping. This sound should stop immediately when you turn off any fixture that is running water in the building.

You may be able to stop or reduce plumbing supply piping noise by changing the water system pressure at a municipal water supply valve. Try first just slightly reducing the incoming water pressure by closing the main water shutoff valve about 1/2 turn while you hear that piercing pipe whistle (you'll have to take one hand off of at least one of your ears to take this measure).

Now we'll get more specific about how we diagnose and fix this horrible water pipe sound

History as a clue in diagnosing building water pipe noises

Main water shutoff with a lead entry main (C) Daniel FriedmanIf you think that this problem was not present when the building was new but has been getting worse over time, that argues for a mineral deposit or debris deposit, possibly along the length of piping but also possibly in a faucet, control, even a fixture spout strainer that is having effect.

Mineral deposits, if that is a factor in pipe noise (see corrugated piping noise research cited below), won't disappear by simple flushing.

If you think that the problem has always been present then I suspect a pipe layout, design, support, or one or more individual valves, controls, or even a pressure tank problem.

Watch out: while you're inspecting the plumbing system be alert for lead supply piping (red arrow in our photo) that may be at end of life or might be a health concern, and look for leaks, inadequate pipe support, or other stuff you failed to notice that you might fix before a plumbing leak becomes a catastrophe.

Running faucets to "fix" a pipe whistle noise by flushing the water system

I'm doubtful that just running all the faucets for an interval will fix a pipe noise, except on the slight chance of flushing out a bit of debris somewhere that happens to block flow so as to cause the flow rate to set up a harmonic vibration or cavitation in the piping system.

Flushing air in water supply piping to remove a pipe whistle or shriek

I'm also a little doubtful that air in pipes would cause an ongoing whistling noise. It is possible to trap a bit of air inside of a horizontal water (or hot water heating system) pipe, and I agree that at least in theory the effective reduced diameter of piping in the area of air trap might be related to pipe noises.

But because unlike heating systems, water flows in building piping generally at higher pressures and flow rates than in hydronic heat (where air traps are more common), I'd expect air to be forced through the piping and discharged at faucets even if there was a recurrent source of air in the system (such as a well piping or control or air volume control defect ).

Details about these points are at

List of Common Sources of Pipe Whistle or Shriek Sounds

I have found a range of plumbing noises, banging, clanking, and whistling that occur when water is run in some buildings and that would diminish or stop entirely when we changed the flow rate to faster or slower than a critical rate that seems to set up a vibration in the system.

Sometimes even a small flow rate such as a filling toilet can cause a horrible shrieking or whistling in the supply pipe system, so I infer that the sound is not simply caused by a high flow rate.

Squeals and shrieks from water pressure tank

A squealing water pressure tank sound is often due to water passing through a restricted valve or pipe clog.

Shrieking from a water pressure tank that incorporates a bladder may be due to a partly collapsed bladder or obstruction at the tank entrance fittings.

Details about this point are at WATER TANK BLADDERS & CAPTIVE AIR

Other Sources of Building Shrieks & Whistles probably not related to water piping

Before beating whistling or shrieking pipes into a quiet state we should be quite confident that the building noise complaint is only related to water supply piping, that is, the whistling or shrieking sound is not related to or caused by the drain system, and more suitably, not related to hot water heating equipment nor hydronic or steam heating system noise.

Details are at

Cavitation in water piping: holes, leaks, valve design as noise sources

A high pitched shriek or whine also occurs during fill-ups of water tanks whose water level is controlled by a float. In that case the noise seems to come from a combination of stick float mechanism that may not fully open the fill valve and thus a partial restriction in the water line.

Some discussion of the effects of holes in piping systems and the causes of cavitation inside the piping system is in order. I suspect, based on limited field testing and a review of research literature that cavitation may explain some water pipe whistling and shrieking. You can demonstrate the hypothesis that cavitation occurs in some water control valves at some valve positions by opening or closing the valve just slightly from its current position.

For example at our offices in Mexico water is supplied by intermittent, varying pressures in the street water mains from which water is pushed by city pressure to a rooftop water storage tank. Water to the building is then fed downwards from that tank - a common system world wide.

I have observed that at times when our rooftop water tank is filling the whole water system produces a horrible shrieking sound that some visitors describe as water pipe whistling. I speculate that the noise is due to cavitation in one of two locations: the inlet water main valve or the float valve that controls filling of the water storage tank.

I find that while the pipe whistle-shriek is active, if I zoom over to the main water shutoff-valve and close it slightly, the shrieking stops immediately. If I re-open it to its prior position the whistle renews until the water tank has filled.

This sound does not always occur, depending probably principally on the supplying water main pressure but possibly on other variables in temperature, even barometric pressure, or the condition of the water tank float valve.
I don't claim this is the only possible explanation of water pipe whistles but it seems a likely one.

We also observed both whistling and banging clanging water hammer in the water supply piping system of the Casa Azul hotel in Queretaro, Mexico - an incredibly loud sound that would appear or disappear depending on how many fixtures were in use and probably on variations in the hotel's water supply pressure.

Water supply pipe shriek or whistle noise diagnostic questions

But I agree I've not researched enough on whistling sounds in plumbing systems. Can you tell me more precisely (you already took a stab at this)

  • What is the building and noise history: how old is the building, when was the pipe whistle first observed, and how has the pipe whistle noise changed over time
  • What are the building piping materials: copper, galvanized iron, plastic
  • What is the building water supply: private well or municipal supply
  • What is the building water quality: is the water supply high in mineral content
  • What is the building hot water performance: how is hot water made and have there been signs (such as diminished hot water flow rate or water heater tank noises) indicative of scale formation in the system
  • Does the noise occur only on cold water flow, hot water flow or either or both at once?
  • Does your home uses a water pressure tank?
  • How does the noise relates to water flow rate and number of fixtures in use
  • Where is the noise is loudest
  • Whether you hear the noise when you're sure no fixture is in use
  • Have you tried, during the whistling, various measures to amend the flow rate of water such as turning the main water supply valve slightly more towards its closed or open position?

Cures for Water Pipe Whistling & Shrieking

Besides these research citations on water pipe noises, people have invented things intended to silence the pipe whistle. Not surprising, some of the inventors also appear among some of the pipe sound research.

Below we include a list of pipe noise reduction measures, starting with a few installation details. But the key steps in managing pipe whistling and vibration caused by water flowing through the piping system involve adjusting the pressure and flow rate in the system.

JGL Acoustics recommends that the maximum water flow rate in gallons per minute in a building piping system ought to be 4 feet per second. Translating this into something a normal human being can understand, that means that water flow in supply pipes should be:

Water Pipe Flow Rates in GPM to Avoid Pipe Whistling or Shrieking Noises

Water Pipe Diameter Maximum flow rate
1/2" 2.5 gpm
3/4" 5.5 gpm
1" 10 gpm


Separately, Canadian CMHC research (1996) found that increasing water pressure increased the noise level in buildings by +5 dBA to +9dBA when water pressure increased from 40 psi to 100 psi (which is high and well above recommended in-building water supply pipe pressures).

Interestingly the CMHC research found that the noise transmission varied by building structure (wood vs steel frame, for example) but CMHC found that there was not a significant advantage in sound reduction obtained by increasing the pipe diameter from 1/2" to 2".

Table data adapted from "Plumbing Noise", JGL Acoustics, publication No. 8, JGL Acoustics, Inc., 6421 Lake Washington Blvd. N.E. # 209, Kirkland WA 98033, Tel: 206-827-1057

Noise isolating pipe hanger, plastic (C) InspectApedia

  • Confirm that the whistle or shriek is due to plumbing: a quick test is to shut off the water supply when you hear the noise. If the noise doesn't stop this is not a building water supply piping problem.
  • Check for running toilets and fix them before doing anything else.
  • Secure loose water supply pipes: on occasion we find pipes that vibrate and wiggle around, perhaps due to cavitation or other water movement inducements. Wiggling pipes ought to be secured anyway to avoid developing leaks.

    When adding water supply piping support use sound-isolating fittings. We list some noise isloating pipe hanger suppliers under plumbing noise silencer devices below. Rigid pipe supports such as metal strapping, clamps, or even the plastic J-hook tpe support are the greatest source of pipe noise tranmission in buildings.
  • Important: Try turning down the water flow rate at the main water shutoff-valve.
  • Important: Try adjusting the water pressure: If there is a pressure regulator on the house side of the main water shutoff valve, as is the case for many municipal water supply systems and if there is no additional shutoff on the house side of the pressure regulator, try setting the pressure regulator itself to a slightly lower pressure.

    Reducing water pressure or flow velocity is the single quickest, least costly step that should reduce building water pipe noise generation.
  • Important: Change the water control valve: the main water control valve or shut-off, or other water flow control valves or devices in the building piping system are one of the most common sources of pipe noise. If you can trace the noise to the valve itself, try changing the valve brand or model. Other than simply adjusting the valve to a lower rate, this may be the least-costly step in shutting up screaming pipes.
  • Important: Change the water pressure regulator: some water flow control valves are more noisy than others. If the water pressure regulator is the noise source consider changing the brand or model of the control.
  • Important: Adjust individual plumbing fixture water supplies: If the shrieking whistling water pipes are peculiar to use of just one or two plumbing fixtures, try adjusting the water supply valve to each of those fixtures. Often closing the valve slightly, or opening it if the valve was mostly shut, will change the flow rate enough to stop water pipe cavitation noises at the fixture.
  • Add water pipe insulation if creaking or pipe movement are contributing to the noise complaint
  • Install a water noise silencer device or noise isolating pipe supports if pipe vibration is a problem
    • Water Pipe Vibration & Noise Isolating Hanger Systems
      • Isolation Hangers, Acoustical Solutions, Inc., Tel: 800-782-5742 USA, Website: http://www.acousticalsolutions.com
      • Isolation Hangers, Vibro-Acoustics, Inc., Vibro-Acoustics Corporate Office 355 Apple Creek Blvd Markham, Ontario L3R 9X7, Canada, Tel: (416) 291-7371 , Email: info@Vibro-Acoustics.com , Website: http://www.vibro-acoustics.com/ Excerpt from the company's information on Isolation Hangers:

        Suspended building systems including equipment, ductwork and piping are either noise and vibration sources or paths which can transmit vibrations into the supporting structure. Structural floor, ceiling and roof systems act as sounding boards, turning these vibrations into audible noise.

        Vibro-Acoustics’ vibration isolation hangers help reduce this problem. Our hangers are typically installed inline with threaded rod supports to break the rigid support path. Vibro-Acoustics’ uniquely-engineered springs are used for low frequency vibrations, and our elastomeric isolators help absorb high frequency vibrations. A combination of both options is also available to maximize performance.
      • Pipe Supports, Vibration Isolators, HVAC Accessories, Chand Engineering, Bal Kalan, Majitha Road, Armitsar (Punjab) 143 001, India, Tel: 91-183-257-3581, Email: info@chandengineering.com, Website: http://www.weicco.com
      • Pipe Supports, James Walker Australia Pty Ltd PO Box 13, Lion Works 32 Clapham Road Regents Park NSW 2143 Australia
      • Spring & Neoprene Isolation Hanger, Kinetics Noise Control, Tel: 877-457-2695, Website: http://www.kineticsnoise.com
      • Vibration Control Products, Mason UK Ltd., United Kingdom, Tel: 44-0 1252 716610, Email: info@mason-uk.co.uk, Website: http://www.mason-uk.co.uk
    • Use plastic water supply pipes when re-piping or installing new water pipes in a building. Hunaidi at Canada's NRC who studied plumbing noise found that plastic piping is about 10 dBA less noisy than copper pipes when both are rigidly clamped. However if you use noise-isolating plumbing supports either pipe material will be equally quiet.
    • Water pipe noise silencing products & systems
      • Molloy, James F. "Combined valve and water silencer." U.S. Patent 2,588,555, issued March 11, 1952.
      • "Quiet anti-siphonic float actuated valve US 2779350 A" an. 29, 1957 I .1. c. OWENS 2,779,350

Water supply pipe noise research: cavitation, flow, whistles, shrieks & Building Plumbing System Noise Reduction Methods

Here are some interesting citations on the topic. They indicate that you and I are not totally weird in looking for a solution to water pipe sounds.

  • Brothers, K., Using the IWA Performance Indicators and Noise Mapping for NRW Reductions in Halifax, Nova Scotia, Canada. Proc. Water Loss Specialist Conference, International Water Association, Brno, Czech Republic, pp. 227-233, 16-18 May 2001
  • Hunaidi, Osama, "Acoustic Leak Detection Survey Strategies for Water Distribution Pipes", No. 79 (2012), national Research Council, Canada (NRC), Website: https://www.nrc-cnrc.gc.ca, retrieved 4/6/14, original source: https://www.nrc-cnrc.gc.ca/ctu-sc/ctu_sc_n79 NRC Construction, Ottawa K1A 0R6 T: (613) 993-2607; F: (613) 952-7673; www.nrc-cnrc.gc.ca/ctu
  • Hunaidi, O., Detecting Leaks in Water-Distribution Pipes, Construction Technology Update No. 40, Institute for Research in Construction, National Research Council of Canada, 2000
  • Hunaidi, O., Chu, W., Wang, A., and Guan, W. Detecting Leaks in Plastic Water Distribution Pipes, Journal AWWA, Vol. 92, No. 2, pp. 82-94, 2000
  • "Plumbing Noise", JGL Acoustics, publication No. 8, JGL Acoustics, Inc., 6421 Lake Washington Blvd. N.E. # 209, Kirkland WA 98033, Tel: 206-827-1057, retrieved 4/6/14, oiriginal source: http://www.jglacoustics.com/acoustics/ss_articles/plumbing_noise.pdf
  • "Research on Plumbing Noises in Multiple Unit Buildings", Canadian CMHC, Research Report: Recherche sur les bruits de plomberie dans les edifices à logements multiples (1996), Technical Series 96-226, retrieved 4/6/14, original source: http://www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/96226.htm
  • "Sound & Vibration Control", 1999 ASHRAE Applications Handbook, retrieved 4/6/14, original source http://www.mne.psu.edu/lamancusa/me458/ashrae_isolation.pdf
  • Fuchs, H. F. "Generation and control of noise in water supply installations. Part 2: Sound source mechanisms." Applied Acoustics 38, no. 1 (1993): 59-85.
    Moussou, P., S. Caillaud, V. Villouvier, A. Archer, A. Boyer, B. Rechu, and S. Benazet. "Vortex-Shedding of a Multi-Hole Orifice Synchronized to an Acoustic Cavity in a PWR Water Piping System." In ASME 2003 Pressure Vessels and Piping Conference, pp. 161-168. American Society of Mechanical Engineers, 2003.
  • MJM Acoustical Consultants, Montreal, PLUMBING NOISE IN MULTI-DWELLING BUILDINGS MJM Acoustical Consultants Inc., Montreal, September 1990. A research project conducted in the acoustical laboratory of the National Research Council of Canada, on behalf of the Canada Mortgage and Housing Corporation. The objective of this research was to determine the acoustical performance of various pipes and plumbing installations; the report is available in both French and English. [This is a long, 133 p. document] http://www.mjm.qc.ca/publications/en/177891_plumbing.pdf

    See http://www.mjm.qc.ca/en/recherche_pub.html for a complete list of research projects
  • MJM Acoustical Consultants, Montreal, REDUCTION OF PLUMBING NOISE IN LIGHTWEIGHT CONSTRUCTION A.C.C Warnock (National Research Council Canada, Ottawa, Ontario) and M.J.Morin (MJM Acoustical Consultants inc., Montreal, Quebec), Journal of the Acoustical Society of America, Volume 88 - Issue S1, P.S135 (1990)
    Noise from plumbing fixtures can be a source of great annoyance in single-family and multi-family homes. Noise-control articles and textbooks usually recommend the use of resilient supports for pipes and other fixtures as a means of controlling noise.
    A study funded by Canada Mortgage and Housing Corporation and undertaken by MJM Acoustical Consultants* at NRC examined the changes in noise level produced by different types of pipes, different methods of mounting pipes, different wall types, and the addition of sound absorbing materials in walls. Noise sources used included an ISO standard plumbing noise source, a toilet, a sink, and five common bathroom faucets. Closed cell rubber foam supports were found to be the most effective of the resilient materials tested, providing reductions in A-weighted noise levels around 20 dB. This article gives a summary of the results obtained; it is available only in English.
    *Plumbing Noise in Multi-Dwelling Buildings, MJM Acoustical Consultants Inc., Montreal, Sept. 1990
  • Moussou, P., Ph Testud, Yves Aurégan, and Avraham Hirschberg. "An acoustic criterion for the whistling of orifices in pipes." In ASME 2007 Pressure Vessels and Piping Conference, pp. 345-353. American Society of Mechanical Engineers, 2007.
  • Nakiboğlu, G., S. P. C. Belfroid, J. Golliard, and A. Hirschberg. "On the whistling of corrugated pipes: effect of pipe length and flow profile." Journal of Fluid Mechanics 672 (2011): 78-108.
  • Nakiboglu, Gunes, Stefan PC Belfroid, Devis Tonon, Johannes FH Willems, and Avraham Hirschberg. "A parametric study on the whistling of multiple side branch system as a model for corrugated pipes." In ASME 2009 Pressure Vessels and Piping Conference, pp. 389-398. American Society of Mechanical Engineers, 2009.
  • Rayleigh, John William Strutt Baron. The theory of sound. Vol. 2. Macmillan, 1896.
  • Testud, Ph, P. Moussou, Avraham Hirschberg, and Yves Aurégan. "Noise generated by cavitating single-hole and multi-hole orifices in a water pipe." Journal of Fluids and Structures 23, no. 2 (2007): 163-189.
  • Testud, Ph, Yves Aurégan, P. Moussou, and Avraham Hirschberg. "The whistling potentiality of an orifice in a confined flow using an energetic criterion." Journal of Sound and Vibration 325, no. 4 (2009): 769-780.
  • Tonon, Devis, B. J. T. Landry, S. P. C. Belfroid, J. F. H. Willems, G. C. J. Hofmans, and Avraham Hirschberg. "Whistling of a pipe system with multiple side branches: Comparison with corrugated pipes." Journal of Sound and Vibration 329, no. 8 (2010): 1007-1024.


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