Quick Answer:
If you hear ticking right after the heater or hot water runs, it’s usually metal or plastic pipework expanding and then contracting as it cools. Most of the time it’s harmless but it can be noisy when pipes touch framing or run through tight pockets in finished walls or ceilings. If the noise is loud, persistent, or spreads through finished rooms, a plumber can verify safe support points and routing.
Why This Happens
Pipes and fittings expand when hot water runs through them and then make clicking or ticking noises as they cool and change shape. The sound is created where a pipe rubs against wood framing, metal hangers, or ceiling drywall. Different materials and clip types make different tones — sharp, single clicks or a series of quieter ticks as cooling happens.
Other causes that mimic the same sound include loose fasteners, mineral buildup that lets a joint move, or new piping laid without adequate padding. For more situations and comparisons, see the note about Ticking after water turned off.
Step-by-Step What to Do
1. Reproduce the noise
- Run hot water then stop and listen for cooling ticks; do this at a sink or shower near where the sound is heard.
- Try different fixtures (hot only and then mixed) to confirm the noise follows hot water use.
2. Listen and feel
- Stand where you hear the sound and press lightly on the nearby wall or ceiling to feel movement; that pressure can help locate which surface is moving against the pipe.
- Note whether the sound fades gradually or stays sharp. A gradual fade usually means normal contraction; a sharp, repeated tick suggests a contact point that may be eased.
3. Check accessible pipe routes
- Look in the basement, crawlspace, attic, or under sinks for exposed pipes. Check clips, straps, and any insulation. Tight metal-to-wood contact is a usual culprit.
- If pipes are insulated but still rubbing, a small strip of foam or pipe insulation between the clip and pipe can stop the noise without major work.
4. Monitor and document
- Take notes or a short voice recording of when the ticking happens and whether any change (temperature, water pressure) affects it. This helps a professional diagnose if needed.
What Not to Do
- Don’t wedge rigid shims or spray foam blindly into cavities; if ticking is near electrical runs or finished ceilings, have a plumber trace the pipe path first.
- Don’t open finished ceilings or drill into walls without knowing what’s behind them — you can hit wiring, ducts, or other services.
- Avoid hammering or forcing pipe supports; that can bend or stress fittings and create leaks over time.
When to Call a Professional
Call a plumber if:
- The ticking spreads through finished walls or ceilings — a plumber can verify safe support points and confirm the pipe path.
- The sound is sharp and repeats frequently after every use, or you find loose clips, bent fittings, or signs of rubbing at a joint.
- The ticking started after recent work such as repiping, or if you suspect the route was changed — in those cases a pro can inspect the routing and supports; see also Ticking after repiping.
Safety Notes
- If you access attics, crawlspaces, or basements, use a flashlight and mind insulation and exposed nails. Wear gloves and eye protection.
- Shut off water to a fixture before adjusting clips or supports. If you see corrosion or suspect a leak, don’t delay contacting a plumber.
- If the ticking is close to electrical runs or fixtures, stop and call a professional to trace the pipe and wiring before any work.
Common Homeowner Questions
- Q: Is this ticking dangerous?
A: Usually not; it’s most often normal expansion and contraction. Have it checked if it’s persistent or correlated with other issues. - Q: Will insulation stop it?
A: Padding or proper pipe insulation at contact points often quiets the noise without major repairs. - Q: Can I fix it myself?
A: For exposed pipes you can add insulation or soft padding. For hidden pipes or near wiring, get a plumber to trace the route first.
For more related articles, see the Ticking or Clicking Sounds During Water Use hub.