Pipes are supposed to be quiet. When yours start banging, whistling or ticking, they're telling you something about pressure, flow or how the pipe is held in place. Most of these sounds have simple causes, and the sooner you pin one down, the easier it is to fix.
Banging when a faucet or appliance shuts off
A loud thud right after you close a faucet, or when the washing machine or dishwasher finishes filling, is called water hammer. Water moving through the pipe stops suddenly, and that energy slams through the line.
Washers and dishwashers are frequent culprits because their valves snap shut instantly. High water pressure makes it worse, and some parts of Central Indiana see city pressure high enough that a pressure regulator is needed to keep it in check.
Water hammer is worth fixing even if the noise doesn't bother you. Every bang stresses joints and fittings, and over time that can loosen a connection inside a wall.
Common fixes include water hammer arrestors at the washer or dishwasher, repairing or replacing a failed pressure regulator, and securing pipes that move when the water stops.
On a well system, a clunk when the pump shuts off can come from a worn check valve.
Whistling or squealing while water runs
A high-pitched whistle usually means water is squeezing through a spot that's too narrow. Hard water is a big reason for that around here. Across Hamilton County, mineral scale builds up inside valves, fill valves and faucet cartridges until the opening is small enough to sing.
A whistling toilet usually needs a new fill valve.
A squeal at one faucet points to a worn washer or cartridge, or a partly closed stop valve under the sink.
A whistle through the whole house can mean a failing pressure regulator or a main shutoff that isn't fully open.
Rattling, ticking and knocking
A rattle while water runs usually means a pipe is loose and vibrating against framing or ductwork. Clamps and straps work loose over the years, especially in basements and crawlspaces where pipes run a long way between supports.
A tick-tick-tick after you run hot water is usually the pipe expanding as it heats and shrinking as it cools, rubbing against wood or a tight hole as it moves. You'll often hear it in newer Carmel, Fishers and Westfield homes plumbed with PEX, which expands more than copper. It's mostly harmless, though adding room at the supports or a little padding can quiet it.
Our freeze-thaw winters make both of these more noticeable, since pipes near outside walls see bigger temperature swings.
Gurgling from drains
Gurgling is a drain sound, not a supply sound. It happens when air can't move freely through the drain system, so water pulls air through the nearest trap instead.
A gurgling sink after the tub drains often means a partial clog or a blocked vent.
Gurgling in several fixtures at once, especially low ones in a basement, can point to a problem in the main sewer line.
In older North Indianapolis homes with clay sewer lines, tree roots are a common cause.
What you can safely check yourself
Note which fixture or appliance sets off the noise, and whether it happens on hot, cold or both.
Make sure the main shutoff and the stop valves under sinks are fully open.
Look along exposed pipe in the basement for loose straps or spots where pipe touches framing.
Watch for damp spots, drips or stains near where the noise comes from.
Leave the pressure regulator alone, and don't force a stuck valve. Both can create a leak you didn't have before.
When to call us
Call if the noise is loud, happens every time you use water, started suddenly, or comes with low pressure, leaks or a slow drain. Your plumber will track down the cause and give you options and a price before any work starts. For banging and pressure problems, see our leak detection and repair service, and for gurgling drains, our drain cleaning and repair page.
FAQ
Is water hammer dangerous?
Not right away, but it's hard on your plumbing. Repeated shocks loosen fittings and can eventually cause a leak, often somewhere you can't see. It's worth fixing early.
Why do my pipes tick when the heat or hot water is on?
That's thermal expansion. The pipe grows slightly as it warms and rubs against framing or a strap. It's usually harmless, and giving the pipe room to move quiets it.
Can hard water make my pipes louder?
Yes. Scale narrows valves and fixtures, which speeds up the water and causes whistling. A water softener keeps new scale from forming.
My new house has noisy pipes. Is something wrong?
Not necessarily. Newer homes can have high incoming pressure, fast-closing appliance valves and PEX that moves as it heats. A quick look usually finds a simple fix.
Will pipe noise go away on its own?
Rarely. Loose supports get looser and scale keeps building, so most noises get louder over time.
Hearing something odd in your walls? Call or text (317) 731-3028, or request service online.
