Advice Reel: Sounds
Banging, Humming and Whistling Pipes
Bang. Hum. Whistle. Tick. Your pipes are talking. Some of it is idle chatter. Some of it is a warning. Here is how to tell which.
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The short version
Every noise has a cause. A bang when a tap or appliance valve shuts is usually water hammer, the shock of fast-moving water stopping suddenly. A hum or vibration often points to high water pressure or a loose pipe. A whistle tends to come from a partly closed valve, a worn washer or a restriction such as scale. Ticking in walls or ceilings, especially as hot water runs, is often pipes expanding against wood framing.
Some of these are a nuisance. Water hammer and high pressure, though, put real stress on fittings, valves and appliance hoses over time.
What you notice, what we usually find
| Symptom | Likely cause |
|---|---|
| Bang when a valve snaps shut | Water hammer: missing or dead arrestor |
| Tick-tick-tick while the hot side warms up | Copper growing longer inside a snug hanger |
| A whistle from just one tap | Tired washer, or its angle stop half shut |
Step by step
- Name the noise. Is it a bang, hum, whistle, rattle or tick? When does it happen: when a tap closes, when the washing machine fills, when the toilet refills, or all the time?
- Find the source. Run fixtures one at a time and listen. Note which room and which valve sets it off.
- Check the shut-off valves. A main valve or fixture stop left half closed can whistle. Open it fully, then back it off a touch.
- Look at loose pipe. In an unfinished basement, check whether pipes rattle against joists. Proper straps and clamps usually solve it.
- Test water pressure. An inexpensive gauge on an outdoor tap or laundry connection gives a reading. Very high pressure strains everything.
Mistakes to avoid
- Ignoring water hammer. The repeated shock can loosen joints and damage valves. Arrestors installed near quick-closing valves absorb it.
- Cranking the pressure regulator up to fix weak flow elsewhere. Low flow at one fixture is usually a local issue; see low water pressure causes.
- Strapping hot pipes too tightly. Hot water lines need room to expand, or they will tick and creak.
- Overlooking the toilet. A fill valve that screams or hums while refilling is worn. A new one is usually a quick fix; see running toilet fixes.
Stop and phone a plumber when
- 1A ceiling or wall starts dripping
- 2More than one drain backs up at once
- 3You smell gas or sewage indoors
- 4A valve will not turn or drips when touched
When to call
Call a plumber when banging is loud and frequent, when pressure tests high, when noises come with drips or stains, or when you cannot find the source. A plumber can install water hammer arrestors, adjust or replace a pressure-reducing valve, secure loose pipe and replace worn valves.
Older Oakville homes with galvanized or early copper piping can be noisier as pipes corrode and narrow. If the noise comes with low pressure and rusty water, read galvanized pipes in older homes and our repiping page. Noises from the water heater are covered by water heater repair.
Straight answers to common calls
Is water hammer dangerous?
It is rarely an immediate danger, but the repeated shock wears out valves, fittings and appliance hoses. It is worth fixing before something gives.
Why do my pipes bang only when the washing machine runs?
Washing machines use fast-closing solenoid valves, which are a common trigger for water hammer. Arrestors on the laundry connections usually solve it.
Keep reading
- Whole-Home Repiping in Oakville
Patch after patch, leak after leak.
- Water Heater Repair in Oakville
The shower runs cold.
- Common Causes of Low Water Pressure
A shower that dribbles, a hose that barely reaches the garden.
- Why Your Toilet Keeps Running
A hiss in the night.
Ready when you are
One call books the visit. Tell us what you are seeing and we will tell you straight what it likely is.