Water Hammer Plumbing Noise FAQs

Diagnostic questions help find & fix the causes water hammer or shock - noisy pipes & fixtures

Banging Hammering Water Pipe Noise FAQs

Banging noise when closing off hot water taps

I have just had a combo boiler fitted, didn't gave a combo boiler before this.

Now I have problem with banging popes when closing off hot tops and after cistern has filled up.

Plumber wants to fit an arrester near stop cock. Cost is about £200. is this the best thing to cure the problem. On 2017-12-14 by Sandra Dawson -

Reply by (mod) - cost of water hammer arresters sold in the UK

Indeed an arrester can stop banging pipes, though that cost *might* be a bit steep.

A Sioux Chief water arrester sold in the UK by Wickes is under £20 - but perhaps your plumber feels you need a larger device or that access to piping is going to require some costly labour.

Plumber charges vary widely depending on where you live but typically a plumber charges around £75 per hour.

So the cost estimate of £200 might be based on the plumber's estimate of 2 hours labour and the remainder in parts.

OR the plumber may also have a fee for travel.

Is it normal for there to be a water hammer noise for 15 minutes after turning water back on?

My husband shut off the valve to a toilet for a minor repair in the tank (something like a float) and when he turned the valve back on he heard water hammer and immediately shut the valve back off.

I have read it is normal for this noise for the first 15 minutes, but he says we need to call an expert because it will cause damage.

Oour home was built in 2004 but is a concrete slab, but should have the regulators in them. he knows 0% about plumbing, but I want to try to simply turn the valve back on to the toilet. what should we do? thanks! On 2017-12-12 by Isabelle -

Reply by (mod) - NO

Isabelle

No it's not normal to hear water hammer for 15 minutes after working on the toilet.

More likely the problem was the specific velocity with which water was entering the toilet. Try opening the valve all the way - if the noise starts in that position try closing the valve a bit - and so on.

Do we need a new well to fix water hammer banging hammering noise?

We hear a loud hammering noise after flushing toilet or using water inside house. is this doing damage? Can it be fixed without getting a new well? On 2017-08-15 by Meandpat -

Reply by (mod) - NO

Water hammer can do damage, causing leaks, burst pipes, damaged valves, and more subtly but more dangerous, leaks at tempeature/pressure relief valves can ultimately clog such a valve thus giving up an important safety device that is there to prevent a BLEVE - explosion.

 

Banging water hammer when water is turned both on and off - Australia

I've read some of the water hammer comments and the noise seems to arise when a tap is turned off.

However the water noise in my apartment in a 3 level complex consists of a loud "bang" (water turned on?)and then the sound of water rushing for about 5 seconds and then a loud bang when it stops.

There's an interval of about 15 mins or more and it happens again.I thought it was the water gardening pipe that runs under my unit but apparently that pipe wasn't being used at the time in question (3 a.m).

I'm aware water hammer is caused by, say, turning a tap off or a washing machine stopping water flow when its full (water stopped) but this noise (first bang) occurs at the start when the water is apparently turned on.

My Building Executive Committee said the noise could be caused by tenants turning on and off their "over pressured taps" or from a dishwasher or washing machine. I'm glad you said a sound recorder could easily record the noise because I'm going to get one and try to get to the bottom of this. Any comment? Thanks On 2016-06-19 by middle Australia -

Reply by (mod) -

It sounds like water hammer to me, and a committee blaming the victim not the cause; record the sounds; consider installing water hammer arrestors.

There are both water-hammer reducing devices that can be installed on the piping near the valve and slower-closing valves that can be swapped in if needed.

I agree it's important to fix this as water hammer can cause damage, leaks, even unsafe conditions (as it can damage a relief valve).

Please see the suggestions at WATER HAMMER NOISE DIAGNOSE & CURE

Intermittent banging when hot water turns on

My water heater was got replaced 6 months ago. Since then whenever the hot water gets turned on, there is a intermittent bang sound occurs. it only happens when hot water turns on.

Just wondering if this is related to the pressure valve. Any idea? Thanks.On 2016-03-24 by Will -

Reply by (mod)

The pressure relief valve won't itself cause water hammer, but as I said earlier it could leak dye to water hammer.

Banging noises can come from there and might be heard after running hot water as the water heater turns on and a combination of heat and scale in the water heater cause it to make banging, popping sounds.

See WATER HEATER NOISE DIAGNOSIS, CURE

IF there are no banging noises at the water heater, then heck out the live link at

Continue reading at WATER HAMMER NOISE DIAGNOSE & CURE

For water hammer explanation and cures. You'll see its probably a water velocity issue, fixed by adding a water hammer prevention device or a slow closing water valve.

Water pipes shake and bang near end of water tank re-fill after using water: related to heat pump sharing same well?

I have a domestic well and a ground-water sourced heat pump that operates off the same well. I have pressure tank with 15 gallon draw and 44 gallon capacity.

Only recently, when water has been running for several minutes and then stops (like when the heat pump has run a cycle and stops drawing water), the well pump fills the pressure tank, when the pressure is almost to the right level, the pipes (plastic) begin to shake and produce loud sound.

The sound last for 15 to 60 seconds, and seems to stop when the pressure tank reaches the shut off setting.

Tank is set to 20/40 psi now, when sounds started it was 40/60 psi. The adjustment didn't help. I've now had two plumbers here a total of six times over two days and they can't find the I ssue. All they have managed to do is mask the sounds with foam pipe I nsulators, foam under the pressure tank, etc. - not addressing the actual cause.

They told me pressure tank operates fine, well pump is operating great too. Thanks for any suggestions, we are not sleeping well for a couple weeks now and need a solution. Appreciate the help! On 2018-03-01 by ChadF -

Reply by (mod) - domestic well and a ground-water sourced heat pump seems to cause noises

Is the pump in the well?

is the pump relay switch chattering?

is the pump having trouble reaching the cut-off pressure?

We may want to pursue those questions and think further before just adding water hammer control devices.

Recapping the key I ssue

When the pressure is almost to the right level, the pipes (plastic) begin to shake and produce loud sound. The sound last for 15 to 60 seconds, and seems to stop when the pressure tank reaches the shut off setting. Tank is set to 20/40 psi now, when sounds started it was 40/60 psi.

I might experiment by closing valves to the ground-sourced heat pump to confirm that the problem does not occur except when the heat pump is online.

When I have seen this shutoff chatter at a well pump it's often been traced to a chattering check valve or control valve that's operating just enough to destabilize the pressure control switch near the cutoff pressure.

by ChadF

Any further thoughts on this? Still having the I ssue. Plumbers have now replaced the well pump, which didn't work. Lucky they said they wouldn't charge me if it didn't fix the I ssue. We are literally going crazy having to have plumber after plumber I here and never getting anywhere. Really need some help folks. Thanks.

The pump relay switch doesn't chatter at all either. Thanks for the help!

The pump is in the well. Plumbers have told me the pump is 1/2 HP and is likely barely large enough, should have been 3/4 HP.

As far as pump having trouble reaching cut-off pressure, the sound happened when the cut-off was set to 60 PSI and was I dentical when reduced to 40 PSI. The pump's amp draw was too high at the higher cut-off but was humming perfectly at the lower. I'm no expert, but it doesn't seem like it's having trouble reaching the cut-off pressure.

by (mod) - noise occurs with the heat pump online and with it offline.

If the heat pump operation is not affecting the presence or absence of a noise, determined by shutting down the heat pump system and observing that the noise recurs, I'd look elsewhere for its source.

by ChadF

The noise occurs with the heat pump online and with it offline. After the plumbers replaced the pump, which had a built in check valve, the noise still occurs, but changed to a more random pattern.

it now occurs I ntermittently, sometimes while the heat pump is running, sometimes after the shower runs, or after/while the washing machine fills. No rhyme or reason.

Could debris become clogged in the manabloc and cause something like this? is it safe to blow air through the manabloc? Running out of options.

Will water pressure surges weakenpipe?

Is it true that repeated high surges of water pressure can weaken pipe over time? if so, would this mean one could extend the life of discharge plumbing pipes by moderating the flow of waste water? On 2017-06-30 by Scott

Reply by (mod) - Surges of water pressure won't weaken pipe but water hammer can cause leaks; Supporting Research

Great question, Scott. My gut feel is no if you're talking about typical residential water piping materials, and if you're talking about the normal ranges of residential water pressure systems, such as between about 20 psi and 70 psi, and if we ignore the connections - it's a connection that is more likely to wiggle, weaken and come loose in response to water hammer.

Watch out: while pressure surges in the range I mentioned should be harmless, that is not the case for actual banging pipes caused by water hammer. That can lead to plumbing leaks and even unsafe relief valve leaks.

There is some expert material failure research that digs more carefully into your question, as well as some theoretical modeling such as

• Schmitt, C., G. Pluvinage, E. HADJ‐TAIEB, and R. Akid. "Water pipeline failure due to water hammer effects." Fatigue & Fracture of Engineering Materials & Structures 29, no. 12 (2006): 1075-1082.
  Abstract:
  
  A numerical model has been established in order to simulate the propagation of pressure waves in water networks. The present model formulation is based on a system of partial hyperbolic differential equations. This system has been solved via the characteristics method.
  
  The current model provides the necessary data and the necessary damping of water hammer waves, taking into account the structure of the pipe network and the pressure loss.
  
  The numerical algorithm estimates the maximum pressure values resulting from the water hammer when closing valves in the network and consequently, the maximum stresses in the pipes have been calculated.
  
  in the case of simultaneous closing of several valves, the over pressure can exceed the admissible pressure. in this case, the severity of a defect such as a corrosion crater (pit) has been estimated by computing a safety factor for the stress distribution at the defect tip.
  
  This allows the applied notch stress I ntensity factor to be obtained. To investigate the defect geometry effects, semi-spherical and semi-elliptical defects are deemed to exist in up to one-half of the thickness of the pipe wall.
  
  The outcomes have been I ntroduced into the structural I ntegrity assessment procedure (SINTAP) failure diagram assessment (FAD) in order to obtain the safety factor value. Conventionally, it is considered that a failure hazard exists if this safety factor is less than two.
• Halliwell, A. R. "Velocity of a water-hammer wave in an elastic pipe." Journal of the Hydraulics Division, 1963, Vol. 89, I ssue 4, Pg. 1-21
  Abstract:
  
  The general expression for the velocity of a water-hammer wave through a fluid in an elastic pipeline is evaluated.
  
  This result is applied to the following common practical cases: A rigid pipeline; thick-walled and thin-walled elastic pipelines with various longitudinal constraints; rock tunnels; and tunnels having a steel, or concrete, or steel and concrete lining.
  
  The results obtained are compared with those given in several standard reference books.
  
  it is shown that certain errors do exist, and considerable confusion does arise with these texts due to the fact that the assumptions made by the authors have not been clearly stated.
  
  Most of the confusion and errors in the texts are concerned with the effect of the external constraints or of Poisson's ratio, and the error I nvolved I s, in general, small (less than 10%).
  
  Nevertheless, this error may be I mportant, and textbooks should make quite clear any assumptions made in deriving their results.
• Lahlou, Zacharia Michael. "Water hammer." Water Encyclopedia (2001).

Reviewing those and other sources suggest that some pipes could fail along the pipe length from water hammer.

Note: Water hammer is not going to happen in drain pipes carrying wastewater - as expressed in your question - but rather in supply pipes that are under pressure.

Do hammer suppressors go bad OR do they get clogged up and stop working

AUTHOR:R.S. (no email)

Do hammer suppressors go bad OR do they get clogged up and stop working because of that? On 2017-04-03 by R.S. -

Reply by (mod) - yes and no

A water hammer arrestor can be damaged by mis-handling during Installation, as Watts points out in their Installation guide.

But typical water hammer arrestor design includes a sealed chamber that should not clog nor fail by leakage.

If the water hammer arrestor never worked satisfactorily I suspect that it was installed in the wrong location or that the wrong size was selected.

Water hammer an occur on a plumbing system as a "new" I ssue also if / when any valve is changed to a different type, such as a fast-closing zone valve on a heating boiler.

Watch out: however some older design water hammer arrestors that don't keep their air charge separate from the water itself can stop working as their air becomes absorbed into the building water supply. That should't happen with more modern water hammer arrestor devices as those do keep their water and air separated.

Cold is OK but I have hot water pressure loss and banging pipes

I have pipe banging I lose pressure on the hot water I still have pressure in the cold water what can cause this ? On 2017-03-20 by Luis G.

by (mod)

Searching InspectApedia using the search box just above and looking for "HOT WATER PRESSURE LOSS" finds this article that may help you diagnose the trouble you describe:

https://inspectapedia.com/plumbing/Hot_Water_Lost.php

I think I'd start by looking for scale in the water heater or calorifier or geyser or hot water cylinder - depending on where you live.

Night time water hammer knocknig noises - caused by watering system that runs at night?

Loud knocks between 2am and 4|30am. NO I nside or outside water is running at that time.

Our home is on a water supply with 300 other homes. The water supply company has 3 wells in our community.

During the day there is no knocking, thumping, sputtering of any kind. THe noise is on the side of the house with the meter.

is pressure from water supply causing this when someone's I rrigation, or swimming pool turns on, or flush of toilet from neighbor between the hours of 2am and 4:30am? On 2016-10-16 by Bill

by (mod)

Bill, if you're sure this is a piping noise, yes the watering system could be the cause. See if the watering timer setting corresponds with the noise.

Other Sources of "Water Hammer" Noise FAQs

Find Source of Random Banging Sounds from Sink, I ndependent of water use - not water hammer

The past 4 months I've been getting random banging sounds from under the sink in the ensuite. it can happen day/night, at times where no water has been used in the house for hours.

The sound comes from somewhere along the pipe in the wall. The house was built in 2009.

Plumbers have come out, it's not water hammer although he drain all water from all taps in the entire house (heard the sound 4 hours later).

I've turned off the main water line at night and have still heard I t. There is no leak, water stains, etc. The last plumber said it may have to do with heating ducts causing expansion and contraction?

(Not sure what the connection is with that, there is a heating vent in each bathroom) The sound is definitely coming from under the sink and it carries over to the pipe under the sink on the other side of the wall in the other bathroom.

I cannot find any pattern as to what triggers I (i.e. it's not after a shower or when the toilet has been flushed, etc.). Any help would be greatly appreciated as it's extremely annoying. I even hear it when I'm on the main floor as the sound comes down through the ceiling. Sometimes I don't hear it all day other times I hear it 10 times in one hour. On 2021-01-19 by Denise

by (mod) -

Denise

Indeed we need more sound recording and tracking work at your house; sounds caused by an event in one location such as a heating system can be picked up and transmitted by nearby materials, so ducts can conduct piping noises and vice versa.

NOISE SOURCE LOCATION - LOG FILES

and other suggestions are

at NOISE / SOUND DIAGNOSIS & CURE

by Denise

I have poured through the resources here and have found nothing that comes close to what I'm experiencing.

I'm ready to call someone in to cut into the wall in the upper level as the sound is so unpredictable and at times can be very loud. Attached is a summary of just today and late last night....interested if you can see anything that I'm missing.

Thank you. I will look at those links later today and can perhaps upload audio. The trouble I s, the sound isn't constant or always repetitive, so it's hard to know when I'll hear it again after the I nitial bang sound.

it can also occur when the furnace hasn't cycled for hours so it's hard to pinpoint if that is the problem or not. I'll give you an update....

by (mod) - Trouble finding source of banging pipes & alternatives to water hammer noise

Consider that the noise you hear may not be water hammer, but other sources of banging noises in buildings such as expanding metal duct work or HVAC noises or other thermal expansion and contraction of materials.

See these t diagnostic articles

• BANGING HEATING PIPES RADIATORS
• BANGING BOOMING NOISE DIAGNOSIS & CURE
• SOUND EVENT LOG 
• WATER HAMMER DIAGNOSIS
• WATER HAMMER CURES

For a confounded noise track down such as the situation you describe, even though it's difficult, the most-profitable course of action is a combination of

- locating the noise source by amplitude (instruments can help)

- locating noise sources by noting what equipment is running or not running

- relating noise to exterior conditions: temperature, sunlight, weather, air movement, occupancy, etc.

For that the noise log I cited earlier and that you've attempted (example above) can help

by Denise - It's definitely not water hammer: Noise log data example given below

It's definitely not water hammer as the first plumber ruled that out. The house was built 2009. I did look at the links you shared but nothing jumped out. If it's due ducts expansion, how could it be that the banging occurs when I haven't used the furnace for 8 hours?

Hi,
Attached is a summary. You will need to put together the pages horizontally, not vertically.

The main source of noise is in the wall between the 2 bathrooms (approx 15' in length) so I'm not too sure I'd be able to pinpoint it much further with a mechanical stethoscope unless I cut into the drywall.

Denise

by (mod) - Example noise log helps track down banging pipe noise

If you've pinpointed the noise to a specific wall it may be time to take a look into the wall: by cuts or a boresope; or you might want to bring an experienced building Inspector or sound engineer onsite. We need to relate the apparent noise sources you suspect that seem in your log to be disparate.

We assembled your Noise Log data vertically simply so that it could be read by most viewers.

[Click to enlarge any image]

 

Water Hammer / Plumbing Noise: Neighbor Complaint FAQs

Annoying plumbing sounds (shower) from townhouse neighbor

I live in a townhouse with common walls, after my neighbour renovated his bathroom I can now hear when he uses the shower, which is annoying and due to his shift work is in the very early hours of the morning.

it's a loud, constant white noise type of sound rather than a hammer.

Your advice as to the cause would be greatly appreciated. On 2021-01-14 by Steve -

- by (mod) -

Steve

I doubt that anyone can give a reliable exact explanation of the noise that you were hearing now from simply a brief text note.

But it's possible that you were simply hearing normal plumbing noises that would be better I solated if there were I nsulation in the common wall between your two living spaces.

That may be something you can add for example by pumping or blowing in foam or a similar sound deadening material. it won't be perfect because the wall framing will still conduct some sound but it should reduce the I ssue.

See SOUND CONTROL in BUILDINGS

by Steve

Ok thank you for your reply, much appreciated.

Water Hammer "Tapping" Noise FAQs

Tapping noise when water is running

Recently added a circulating line and pump to my water heater. As a precaution, I also added an expansion air tank.

I am on city water, so I have great dependable water pressure. I do have an I rrigation system, but that is closed off because it is winter.

Since the install of my pump, I am experiencing a tapping when a faucet is open an water flowing.

I have I colated the noise to be a backflow valve, which was previously in place, but now is making a noise as if it were opening znd shutting constantly while water is flowing....approximately every "second". Could the circulation pump cause this? Could the expansion tank cause this? These are my only two main variables. On 2020-12-24 by Roland

by (mod) -

Roland

Indeed that sound could be coming from your pump. I've encountered exactly that problem in a water system that we recently Installed. it depends on the type of pump and where it is Installed. Maybe you could tell me more about that.

Water heater source of banging noises ?

My water heater makes a low knocking noise

What is causing my water pipes to randomly have a low knocking noise and I just put in a new water heater about a week ago but this was going on before I put the new water heater I n? On 2020-12-23 by Tony

Reply by (mod)

That's not a water hammer problem but more-likely a water heater banging noise.

See the diagnosis and repair advice given

at

• BANGING WATER HEATER

Water Meter / Pressure Regulator Water Hammer FAQs

Water Meter Might be a Water Hammer Noise Source

I have a somewhat different water pipe noise problem.

A couple weeks ago, I noticed noise -- thump, thump, thump, -- about 2-3 times per second and continuing for about a minute coming from the water line in my garage.

The line, (PEX pipe) installed 2 years ago to replace the original line that was leaking, runs from a meter by the street, underground and then up through a hole in the garage floor to the ceiling and finally around two walls to the shutoff and pressure regulator next to the hot water tank.

The noise is not very loud. I can usually hear it only when I'm in the garage. But I can feel the pipe shaking when thumping. I'll guess it occurs a few times each day.

My plumber I nitially said it was caused by a failing regulator but then he found the thermal expansion tank was full of water. He attached a pressure gage to a spigot and told me to not run water until he returned in an hour with a new tank. The pressure stayed constant (~60 psi) until he returned so he replaced the tank and not the regulator.

Next day I heard the thumping again. The plumber convinced me to also replace my 16 year old Rheem water heater although in my experience, Rheem tanks last over 20 years.

But the following day and subsequently, I've heard the thumping again. Twice when this was occurring, I checked the water meter to verify no water was running. Once I went in the house and opened a faucet but the thumping did not stop right away.

The house is in Prescott, AZ and was built in 2004. The supply pressure is rather high -- 110 psi and about half of the water lines in my development have failed but I believe the failure is due to I mproper filling of the trenches with chunks of basalt rock rather than the proper sand bedding and shade fill.

The replacement line was properly installed and Inspected by the city. Another nearby development is at the same altitude, thus likely similar pressure but homeowners there do not report water line failures. Several neighbors I've asked do not report not hearing similar noises.

What to do next? - 2020-11-30 by Fred O

by (mod) - water meter Noises - check for clandestine water use

if there were really no water movement through pipes then what might cause pipe "noise" in the first place?

Possibly some other, even outside, mechanical noise source that's being picked up and transmitted by the piping

or

a local pressure booster pump

or there is a leak somewhere that's not been found. Don't forget to check for water that's running in secret, such as a running toilet.

I F water is flowing in the home but the water meter isn't registering that water use then the meter is probably damaged and that might Indeed be the noise source.

It might be Interesting to use a mechanic's stethoscope on the water pipe at several locations when you are hearing the mystery noise

by Fred O - I suspect the water meter is the noise source

RE: "It might be Interesting to use a mechanic's stethoscope on the water pipe at several locations when you are hearing the mystery noise".

Thanks again for your advice. I can feel the pipe shaking slightly where the pipe is exposed. Also see below.

Today, a new development. Rather than "thump, thump, thump" at a moderate volume, we heard "tap, tap, tap" at faster cadence and lower volume. We could also feel the tapping on the pipe but it was not as prominent as earlier.

I went out to the water meter, which is in a box just below ground next to the street and I could feel the tapping on the meter. Again, no water flowing and the spinner on the meter did not move. A bit later, the thumping returned, louder than the tapping but I think at lower volume than the thumping before.

I now suspect the meter. A week ago, I called the Prescott building Inspection dept. and left a message They have not called back. I plan to leave an email msg.

RE: "If there were really no water movement through pipes then what might cause pipe "noise" in the first place?"

A couple times I've looked at the water meter when the pipe was thumping but did not see any movement. Once, I noted the position of the spinner and saw it in the same spot 30 minutes later.

"Possibly some other, even outside, mechanical noise source that's being picked up and transmitted by the piping or a local pressure booster pump or there is a leak somewhere that's not been found."

I I ntend to try feeling the meter for vibration next time I hear the noise. But it occurs only occasionally. Only pump is the hot water recirculator and that's on a count-down timer that I installed myself. As for leaks, the water bill has not been elevated.

Tis a puzzlement. Thanks for your thoughts. I've asked my city building dept. but they have not answered my query.

Water hammer noises traced to heating radiators

My radiators are banging so loud that a pipe in the basement popped. I sealed it temporarily with a screw. I located a leak , due to the radiator not being tightened enough.

one of the small pressure valves in the basement is leaking water at the part where only steam is supposed to come out. I am so done. help me please. On 2016-03-21 by Antoine

...

I live in Plymouth Wisconsin. Are you aware of, or can you direct me to, a website/phone number which will help address violent radiator hammer sounds in my building apartment? I have approached the building manager and landlord to address/repair the problem and they have been dismissive.
Do I have any recourse other than treating this as tenant vs. landlord legal matter? Thank you. Sincerely, Robert F bobbyofallon@gmail.com - On 2015-11-13 by Robert F

by (mod)

Sure Antoine and Robert F

See BANGING HEATING PIPES RADIATORS 

to diagnose and repair this trouble. Usuallly the problem in your case is condensate is not returning.

Water Hammer Arrestor Location FAQs

installed water hammer arrestor at the water pressure tank

I installed my water arrester at the pressurize tank. Our water source is an overhead tank, water pump is located lower than the source and check valve next and pressurize tank after.

But hammering still exists and is annoying every time the pressure switch shut-off. Please give me more details location of tapping the said device. thanks 2016-01-21 by robert

by (mod) - wrong location

Robert

it may be that the Installation location you chose is not the best - see WATER HAMMER NOISE DIAGNOSE & CURE about locating the water hammer arrestor near highest fixture.

On 2015-11-08 by Andy

Thanks. I'll give it a try.

On 2015-11-08 by (mod) re: where to install the water hammer arrestor.

I'm over my head here Andy and uncertain between following the mfg's generic I nstructions - which places the arrester ahead of the highest fixture - and your observation that you find the hammer occurring near the point of water entry; from your description it seems reasonable to install the water hammer arrestor ahead of the booster pump.

And you'll be conducting some water hammer science: do let me know if that does the trick.

On 2015-11-07 by Andy

Follow up on Reader Question: where to install the water hammer arrestor.

Thank you for your advice. Regarding the size of the arrestor, there is really only a single device: the booster.

The main line into the house goes directly to the pressure regulator/booster pump, and then on to all of the "fixtures" in the house. Since the hammer appears to be between the main shutoff valve on the supply side to the house and the regulator, would this be considered "one fixture", or should I attempt to cover all of the fixtures in the house past the booster pump? Thanks again.

Question: How to I dentify Water Hammer Noise in Buildings

(Apr 25, 2015) Chad said:
While water is running through the shower, I suddenly have the water shut off, and there is loud banging in the walls. After reviewing multiple posts, I have not see that others are havinng I ssues with the water shutting off. Would this still be considered water hammer, or something else?

(July 3, 2014) Krystyl Cruz said: when I flush the toilet there is a loud sound like a jackhammer

When I flush the toilet, a few seconds later (when the water is refilling) a loud sound like a jack hammer comes from the wall behind the toilet. Sometimes if I turn the faucet on in the sink the banging will stop, but if I turn the faucet back off the banging starts again until the toilet stops running.

(Mar 1, 2015) D said:
When turning off hot water I hear a banging

(June 9, 2015) Anonymous said:
When toilet is flushed or cold water is run there is a loud noise which goes away when the hot/cold water taps are run. This only happens in warm weather.

(Sept 10, 2015) Robin said:
When I turn my bathroom faucet on, the pipes start clattering. it mostly does it when I turn the hot water on. Could this be caused by dirty I nlets in the faucet? I didn't have this problem until the plumber installed a new hot water tank.

Reply: the above are all examples of water hammer noise

Thanks for the questions, Chad, Krystyl and D and others. If the water flow stops, that is a separate problem from the loud banging. I'd guess that the banging is Indeed water hammer - which can occur when water supply shuts off suddenly in a piping system. But the banging is not likely to I tself be the *cause* of the sudden loss of water. That sounds more as if a valve is closing.

You are almost certainly describing a water hammer problem. I've found just the symptoms you describe I ncluding that opening a faucet, because it changes the flow rate and pressure in the piping, can move the flow rate off of that speed that is causing the horrible banging sound.

Since water hammer is a feature of water flow velocity and is affected by loose pipes, or valves that close suddenly, I 'd look in detail at exactly what has changed; try slight adjustments to water pressure.

Robin: Of course you'll want to clean out dirty faucet strainers but I doubt that's the source of trouble unless those conditions have changed the water flow rate. in fact water hammer is more likely to appear when water velocity is faster so cleaning out clogs may I ncrease I t.

Question: does water hammer in my plumbing system cause damage?

What effects can water hammer have on my house plumbing system? Other than making noise, does it actually hurt anything?

Reply:

Water hammer causes a sudden "banging" of water supply piping that creates movement and stresses in the system, not just annoying noise.

Water hammer can cause loosening of water supply piping connections, leading to plumbing leaks and related damage

Watch out: Water hammer shocks to the water supply system are more serious at higher operating pressures. On hot water heaters the TP valve is usually set 20 to 30 psi above the anticipated maximum system water pressure. This is high enough that the relief valve won't leak or spill when water hammer occurs in thte system. But at higher water pressures, say 70 psi to 90 psi, the relief valve may be damaged or leak when water hammer occurs.

At our article on WATER PRESSURE REDUCER / REGULATOR you 'll see that we recommend against operating a home at pressures above 70 psi because of the I ncreased risk of plumbing system or plumbing fixture leaks. [10] paraphrased

Question: can I record water hammer noise? Loud banging that isn't water hammering?

(Oct 27, 2011) I an Anderson said:

Hello, is there sound recording equipment to prove water hammer noise from neighbours flat?

(Jan 15, 2012) Anonymous said:

Mike I have a 75 gallom power vent gas water heater the home is well water there is a check valve on the cold water side of the water heater there is also a expanshion tank and both are between the ball valve and the hot water heater.

I am getting alot of load banging on both the hot and cold side when water is running and it I sent water hammering because I put air arresters on system it's happening when both cold and hot are running.

I was wondering if it was the check valve causing the banging sound ?

Reply:

Ian, you can use any recording equipment, even a sound recorder on a cell phone to record the sounds you describe. I've done that with great success.

If you are using a cell phone hold it against a noisy wall or ceiling for strongest sound transmission into the device.

Anon: Putting air arresters onto the system may not have been enough to cure the water hammer if they were too small in capacity.

Question: loud hammering noise wakes me up

(June 21, 2012) jt said:

I am hearing loud hammerins noises, loud enough to wake me up, in the middle of the night. it sounds like the tap is being turned off and on but this is not the case.
When I do use the tap, it only makes the banging noise if I turn it on and off very sharply.
What can I do?

Reply:

JT, if the loud hammering noises are in the water supply piping, it seems most likely that someone is turning water on and off, or a well pump is turning on and off on I ts own - if you have a well pump try checking out causes of the well pump "turning on by I tself".

Securing loose piping and Installing a water hammer control device (described in the article above can also help stop the problem.

Question: various banging, moaning, clanging plumbing noise complaints

(Sept 2, 2012) Tom said:

The noise is not as much about banging but a loud moan in the hot water line between the washing machine and the Master bath tub supply, although if you flush the toilet the noise stops until the tank is filled.

Have tried everything from turning off the water and draining all the lines and refilling each line in different sequences, nothing works?

(Jan 4, 2013) Ted L. said:

Thermal Expansion: When water is heated in the Water Heater it causes water to expand thus an I ncrease in water pressure.

A Code requirement and solution is to install an Expansion tank on the cold water supply line ahead of the Water Heater. The rubber gland will absorb the expanded water and release it when a tap is opened. Expansion problems prevail when no water is being used and the tank is heating.

(Jan 19, 2013) Gary S. said:

I live in a 37 unit appartment and at nightime I can hear a low pounding noise in the distant Would this noise affect the heat temp in my unit. I have hydronic heating.

(Feb 25, 2013) Ykip said:

I experience a severe water hammer when turning on and off the bathtub spout. How can I fix the water hammer arrestor on I t? it seems I mpossible. The water pressure to the house is normal and about 70psi. I appreciate anyone to help me. Thanks,

Question: Rumbing pipes under the toilet

(Mar 5, 2014) Help! said:

My house pipes seem to rumble under the toilet. The toilet is upstairs
I have a water tank in the loft and also a water tank in a cupboard upstairs.

The time does not appear to be defined by any one event (the heating coming on, the water heater turning on, washing machine going).
However this rumbling also sometimes goes 'off' if you sit on the toilet or simply walk into the bathroom.

The times are also I ntermittent. Sometimes it doesnt rumble at all, sometimes once every hour, sometimes every few hours or sometimes every 20 minutes (which drives me mad!)
But the 'rumble' does cease when the toilet is flushed (for a time)?

I am not in any way DIY minded so do not feel comfortable I nvestigating the problem myself.
However wondered if you could perhaps assist in telling me what it is and assumedly I need to get a plumber - how much it would potentially cost to fix?
Thanks,

Reply:

Help.

This rumbling doesn't sound like water hammer. Water hammer is a percussive "BANG!" that or maybe "BANG BANG bang clank" short duration clamor that occurs when water is running (fast and at high pressure and flow rate) and then is suddenly shut off.

If it's not a coincidence, sitting on the toilet or walking into the bathroom wouldn't be expected to I mpact a water hammer problem so I suspect we're looking for something else.

Let's start by trying to I solate systems to find out which system is responsible. I suspect we're looking at something related to heating, not water supply, or a water heater.

Water heaters that have formed a scale deposit on the heater bottom will often make an ongoing rumbling popping sort of sound * when the heater is operating * that I s, when it's heat source is on.

So when you hear the noise let's notice what systems are running and which are off.

Or you could turn off the water heater for say half a day and see if the noise abates.

Search InspectApedia for "Water Heater Scale" to read more about this hypothesis.

Keep us posted and we'll pursue I t.

Question: water pressure booster pump noise

(Mar 9, 2014) Anonymous said:

water pressure booster pump noise going through my water pipes what can I do?

Reply:

If th problem is not a banging when water is turne off in the building then I guess you refer to the transmission of noise from the pump motor. You'll want to look at sound-isolating fixtures to I solate the vibrating piping from the building structure. Regular pipe hangers won't do I t.

Question:

(Apr 3, 2014) ron said:

at our cottage the water system was fine. I ts a submerable pump with an air bleeder valve just before the electrical switch. I ts 25 yrs old. however it seams that when we replaced the tap in the shower the pipes started to shake and water spurts out. This happens after we have used the water system for a bit then it keeps banging/shaking/spurting. also when filling the toilet. thanks

Reply:

Ron,

It's not a complete surprise; sometimes when we simply change the water flow rate we change the vibration behaviour of the system.

It might be diagnostic to open a tap when you hear the banging water hammer noise. Openign a tap elsewhere changes the pressure and flow in the system.

I'd also double check that nothing has changed on the water supply end.

Let me know what you find.

Question: banging noise in pipes at night, 3-5 seconds apart, 7-8 bangs

(Apr 3, 2014) Dave said:

My question is this. At night I am hearing a banging in the pipes every 3-5 seconds of approximately 7-8 bangs. They can be felt when touching the pipes from the laundry room. They are not overly loud. The seem to go away for a brief time when I run the water at the lowest faucet in the house. Any I deas?

Reply:

Dave

You're probably describing water hammer as we discuss it above.

Question: trouble tracking down water hammer noise

(Apr 19, 2014) Lynn Pepe said:

For the past 5 days, we hear what sounds similar to water hammer, can not pinpoint where it is coming from. Tbis happens any time of day or night, does not seem to be related to turning water on or off. We have tried shutting down the main and running the water out several times. We have had the water company to check. what can this be???

Reply:

Lynn, I would be just shooting in the dark to guess very specifically, but surely if you hear the sound when water into the building is shut off completely it's not a water supply system problem. At that point I 'd be looking at hot water heating, steam heating piping, and if those are ruled out, I 'd be looking for other sources of mechanical movement.

Question: will the Temperature & Pressure relief valve protect the hot water tank against water hammer damage?

Will the T&P valve protect the tank against breaking from excessive water hammer? - Watts

Reply:

An "excessive" water hammer is an abnormal but momentary condition that causes a very brief surge in water system pressure. The pressure-relief component of a temperature and pressure relief valve can only discharge a verly limited amount of the surged pressure during the moment of shock of the water hammer event, possibly none.

If water hammer is causing frequent opening of the temperature and pressure relief valve there may also be a risk that the frequent passage of hot water through the valve deposits scale that eventually accumulates to a level at which it prevents safe reliable operation of the valve in an emergency.

And the fact that temperatures I nside the hot water storage tank are elevated above cold water temperatures makes no difference - with the exception of the warning we I ssue next.

Watch out: if the hot water tank is in an abnormal overheated condition, that is water in the tank has become superheated above I ts atmospheric boiling point water hammer could actually lead to a water heater tank explosion. According to Watts Regulator Company, "Water hammer conditions are believed to be a partial factor in starting off an explosion of overheated tanks besides "pressure heat rupture". [10] paraphrased

Question: septic pump check valve noise

5/29/14 Naaj said:

Water-hammering noise from check valve in septic sump pump…solution?

Reply:

Check that you don't have multiple check valves installed on the same piping system. If there is only one then you're ok on that score and you'll want to install an anti-water hammer noise product such as those discussed above.

Question: ball cock in the water tank in loft causeing water hammer

(Oct 18, 2014) mr conner said:

can it be the ball cock in the water tank in loft causeing water hammer

Reply:

No, not directly but possibly indirectly:

Water hammer is an effect of the velocity of movement in water pipes along with pipe dimensions and layout, combined with a sudden STOP! of water flow.

Any valve can "cause" the effect to be heard. Some plumbers install slow closing valves to reduce the problem but you'll read other solutions in the article above.

Question: banging pipe I ssues

(Nov 3, 2014) Hope said:

We recently had I ssues with banging pipes in our home. A plumber recently came out and replaced the water pressure regulator along with adding an expansion tank to our water heater but now after a month or so the noise is back and isn't happening when the water is running like it was before but when the water softner is running. Please help...what could the problem be now?

Reply:

Hope,

I'd like to help but with not a shred of Information about your home, piping, water supply, pressure, valves, usage, etc. my best advice remains in the article above. If any part of that is unclear please just ask.

Question: banging pipes and water softeners

At my home (Cypress Texas), we hear water hammer noise at the end of water softner regeneration cycle. There was no water hammer prior to installation of water softner.

I brought in the water softner Installer and could not figure out why and told may be water pressure is high when the regeneration cycle occurs. He changed regeneration cycle time from night to afternoon and we still have water hammer.

The regeneration cycle is after 10 days and lasts for 1 hr 45 minutes. Did water softner not installed properly? The house was built in late 2010 (by village builders a subsidiary of Lennar Homes). We had water water softner installed in 9/2011.

We purchased this new home and moved in April 2011. I called in a plumber and he was not much help. I am considering to contact the plumbing company (New Tex) who did the original plumbing in the home. May be they can figure out and fix this problem. Any guidance you have. Thanks (Nov 18, 2014) A Kang

Reply:

AK

Ask about Installing either an appropriate water hammer control device (described in the article above) or a slow-closing control valve on the supply to the water softener.

Question: why does water hammer noise suddenly appear in a building?

(Apr 12, 2015) Carl C said:
Why would my plumbing suddenly start making water hammer bangs when it never did before? Nothing changed in my plumbing or any appliances, yet I start hearing significant water hammer. Yesterday, all was quite as it has been for years, then today I hear water hammer. Any I deas?

Reply:

Great question, Carl. I can speculate that

- water pressure may have I ncreased at the source

- a pipe or fixture has come loose

- a control valve has been opened or closed to a different extent than previously

As water hammer is related in large part to velocity of flow and sudden stopping, a change in a valve can be enough. Certainly something has changed so let's start with that assumption.

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Thank you to our readers for their generous comments

Thumping noise traced to neighbor's water meter

RE: "IF water is flowing in the home but the water heater isn't registering that water use then the meter is probably damaged and that might Indeed be the noise source."

I FINALLY have the answer (probably) and you were essentially right --
When the thumping noise was occurring, I checked my next door neighbor's meter, which is adjacent to mine and next to the street. I could feel the vibration there and the meter indicator was spinning rapidly and jerkily. So the problem is a meter -- my neighbor's.

I have notified the city water dept. (I rarely see the neighbor). On 2020-12-17 by Fred O -

by (mod) -

Fred:

Thank you very much for taking the time to write this very helpful water hammer noise update.

You can teach an old dog new tricks.

I will add to our list of steps in tracking down noises in plumbing systems, meters, etc. to remember to check not just your own but other nearby water meters, pipes, etc. that may be those of a neighbour.

A loud banging sound from the plumbing when they use the Guest washroom - solved by InspectApedia

We have a guest bathroom which is not all that frequently used. Recently friends from Poughkeepsie New York visited us here in Ontario.

I was surprised to hear a loud banging sound from the plumbing when they use the Guest washroom.

This morning after their departure I reviewed this very helpful page WATER HAMMER NOISE DIAGNOSE & CURE and learned about the causes of this irritating hammer-like sound.

Happily the solution was easy and one I learned about from this page.

I adjusted the water flow by opening the water shut off to the side of the sink on the hot water side and the noise went away.

Thank you very much! The next time my friends from Poughkeepsie visit I won't have to be embarrassed by my plumbing sounds. :-) On 2016-10-04 by David H. -

Reply by (mod) Banging Pipes in Ontario

David,

Thank you for the nice comments. We work hard to provide authoritative, unbiased information, so we're thrilled when a reader finds InspectApedia.com useful.

We also welcome questions, content suggestions, and critique, so don't hesitate to ask. Working together makes us smarter.

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