Low Water Pressure Repair
Find out why showers and taps have gone weak, from a scaled aerator to a worn regulator.
Plumbing guide
Water Hammer Noise in Avondale, AZ Homes: What to Do
A loud bang from the walls when the washer stops or a faucet closes is water hammer. It is not just noisy. Repeated shocks can loosen fittings and wear out valves. The cause is usually easy to find.
By the Avondale Plumbing Co. team ·
What water hammer is
Water moving in a pipe has momentum. When a valve closes quickly, the water stops and the energy has nowhere to go. The result is a pressure spike that makes the pipe knock.
Washing machines, dishwashers and ice makers have fast valves, so they are common triggers. A single-lever faucet can do it too.
Check the pressure first
High pressure worsens water hammer. A gauge on a hose bib gives the figure. Many homes run between 40 and 80 psi, so a reading far above that is a clue.
If the pressure is high, a pressure regulator near the main may have failed or may be missing. A plumber can test and replace it.
Loose pipes and missing straps
A pipe that is not fastened can slap against framing when the pressure spikes. In an attic or crawl space, look for pipes that move when water changes.
Adding straps with a small cushion stops the knock. If the pipes are behind finished walls, a plumber can locate the section.
Water hammer arrestors
An arrestor is a compact device with an air chamber that soaks up the shock. It goes near the quick-closing valve, for example behind the washer. Some houses had them from the start, and they wear out with age.
A new arrestor often ends the banging, and a plumber can put them in the right places.
Water hammer causes and fixes
Most banging has one of these causes.
| Cause | Clue | Fix |
|---|---|---|
| High pressure | A gauge reads well above normal | Test and replace the regulator |
| Loose pipes | Knocking that moves along the framing | Add straps with cushioning |
| Missing or failed arrestor | A bang when the washer stops | Install a new arrestor |
| Waterlogged air chamber | Noise in an older home | Drain the system to refill the chamber |
Air chambers that have filled
Older houses may contain short vertical stubs in the wall, known as air chambers, that absorb the shock. With time they fill with water and stop cushioning.
Draining the system can bring them back. Close the main, open the highest and lowest taps, let the lines empty and restore water slowly.
Worn valves and washers
A worn faucet washer or a loose valve stem can chatter and bang. If the noise happens at one fixture only, check that fixture first.
Replacing the cartridge or washer is often all it takes. See faucet and sink repair for details.
Why it is worth fixing
Repeated shocks can loosen joints and start leaks. A pipe that bangs for years is more likely to fail at a fitting. Fixing it early protects the plumbing.
If the noise started right after plumbing work, mention that to the plumber.
What repeated shocks do to joints and valves
A sudden pressure spike pushes hard on every joint, valve and fixture connection along the line. Over months and years, that stress can loosen fittings and wear out washing machine valves and faucet cartridges.
Pipes that knock also tend to be pipes that move. In a wall or an attic, repeated movement can chafe a line against a nail or a rough edge and cause a pinhole leak.
Finding the trigger
Walk the house and note which fixture causes the bang. Run the washer, dishwasher and each faucet one at a time and listen. The trigger is usually the fixture with the fastest-closing valve.
Write down where you hear the noise as well. Sound travels along pipes, so the bang may seem to come from a room far from the trigger. A plumber uses the pattern to choose where an arrestor should go.
What a plumber does about it
The plumber reads static pressure, tests the regulator and looks over reachable pipe for loose runs. High pressure may call for a new regulator, and moving pipes call for straps and padding.
If those steps do not end the knock, arrestors are added near the fast valves. Ask whether the work includes testing after the fix, so you know the noise is gone.
Simple habits that help
Close faucets smoothly instead of snapping them shut. Avoid running the washer, dishwasher and a shower together if the pipes knock under load. Small changes in habit reduce shock while you wait for a permanent fix.
Keep a short log of when the noise happens and which fixture was in use. A plumber can use the log to decide whether the fix belongs at a regulator, an arrestor or a loose strap.
When the noise points to a bigger problem
A bang that comes with a pressure drop, a wet spot or a rise in the water bill can mean a leak is developing at a stressed joint. In that case, shut off the water to the affected area and look closely.
Persistent noise in a house with older metal pipe can also be a sign the pipe is aging. If other signs of wear are present, ask about a pipe inspection.
When to call
Phone if the banging is loud, pressure is high or a leak shows up near the noise. A plumber can read the pressure, find the trigger and choose the fix.
Read low water pressure repair for regulator and pressure work.
Common questions
Answers about water hammer
It can damage joints and valves over time. It is worth fixing.
The washer valve closes fast and stops the water suddenly.
Draining the system and securing pipes are simple. Regulators and arrestors are better left to a plumber.
Yes. High pressure makes the shock stronger.
Often yes, if the arrestor is placed near the trigger.
A single hit seldom bursts a pipe, but repeated shocks loosen joints and wear out valves. Deal with the cause early.
Related services
Faucet & Sink Repair
Cure dripping faucets, sluggish flow, frozen stop valves and weeping hose bibs.
Repiping & Whole-Home Pipe Replacement
Swap out worn supply piping across the house once patching no longer holds.
More plumbing guides
Causes of low water pressure
Weak showers can come from one clogged aerator or from a failing main line. Narrow it down by checking where the weakness shows up.
PEX versus copper pipe
Both work for repiping. Learn how they differ in cost, install, heat, water chemistry and repair.
Water heater leaking from the bottom
Moisture at the bottom of a tank may come from a fitting, a valve or the tank body. Here is how to tell them apart and what to turn off first.
Pipes banging?
Call and say when it happens. The dispatcher will line up a plumber for you.