Quick Answer:
If you hear banging in your pipes when no water is being used, it’s often caused by pressure surges in the supply line or by water hammer from fast valve closures. Start by noting the exact times the bangs happen, try to localize where the sound comes from (near the water heater or the main shutoff), and check whether neighbors or the city are doing work that could change system pressure. If the pattern points to supply-side issues, a licensed plumber can confirm the cause and adjust pressure controls safely.
Why This Happens
Two common reasons for unexplained banging are sudden pressure changes on the supply side and internal pipe movement from quick valve actions. Supply-side pressure spikes can come from the municipal system closing or opening main valves, pump cycling at a booster station, or pipe flows changing nearby. Localized causes include a failing pressure-reducing valve, a water heater valve slamming, or loose pipe straps.
If the timing matches periods when the city is working on mains, the sequence often lines up with service changes; **Banging started after city pressure work** is a pattern some homeowners report. Cold weather can also make pipes more likely to bang when water moves, particularly where expansion and contraction occur.
Step-by-Step What to Do
1. Note the exact time
- Write down the time and frequency of each bang. A pattern (same minute each hour, or during certain parts of the day) helps diagnose supply-side vs. household causes.
- Keep this log for at least a day or two; short, repeated entries are more useful than memory alone.
2. Check outside causes and neighbors
- Ask a neighbor if they hear the same banging or if they’ve seen city crews working nearby. If multiple homes report it, the problem is likely on the supply side.
- Note whether the bangs coincide with times of typical municipal work (early morning or late evening). If you know city work was recent, that can point to external pressure changes.
3. Listen to localize the sound
- Walk the house and listen near the water heater, the main water entry, and major branch lines. Placing your ear near those points can tell you whether the surge is coming from the house plumbing or the main supply.
- If the sound is strongest at the main shutoff or meter area, it often means supply-side pressure or the pressure regulator may be involved.
4. Inspect visible fixtures and supports
- Check that visible pipes have secure straps and that loose pipes aren’t rubbing against framing.
- Look for dripping or small leaks at faucets and valves—sometimes a valve opening or closing quietly can cause the bang.
5. Monitor for weather-related patterns
- If the banging shows up with cold snaps or when outdoor faucets are used for freeze prevention, consider that temperature-related contraction is contributing. Search the house after cold periods to see if the timing matches. Many homeowners find that **Random banging during cold weather** explains occasional noises.
6. Decide next steps
- If the log and listening point to an internal issue you can safely address (loose strap, visible leak), make that repair or schedule a plumber.
- If bangs continue with no fixtures running and you suspect pressure spikes, have a plumber evaluate pressure control components rather than attempting more invasive checks yourself.
What Not to Do
- Don’t start opening walls to chase sounds. That risks damage and often won’t reveal the cause if the issue is in the supply line or behind walls you can’t easily access.
- Don’t disable safety devices such as pressure-relief valves, expansion tanks, or the main shutoff. Those are there to protect the system and your home.
- If bangs continue with no fixtures running, have a plumber evaluate pressure control components.
When to Call a Professional
Call a licensed plumber when:
- The banging is frequent, occurs with no fixtures running, or coincides with signs of high pressure (dripping faucets, leaking fittings).
- Your timing log and local checks suggest supply-side pressure swings (neighbors affected or city work suspected). A plumber can safely test system pressure, inspect the pressure-reducing valve, and coordinate with the utility if needed.
- You find damaged or corroded pipes, or if repairs would require cutting into walls or modifying safety devices—let a pro handle those.
Safety Notes
- Turn off power to a water heater only if you know how and if it is safe to do so. For gas heaters, do not disable the gas or safety controls—call a pro instead.
- Never remove pressure-relief valves or other safety equipment. Those parts prevent dangerous pressure buildup.
- If you smell gas or detect a strong leak, evacuate and call emergency services immediately. For water-only issues, shut off the main and contact a plumber if you cannot stop damage.
Common Homeowner Questions
- Why do I hear banging only at night? Nighttime quiet makes faint noises more noticeable; municipal pressure changes or overnight irrigation cycles can also occur then.
- Can I fix pressure spikes myself? Simple fixes like tightening loose straps are safe; adjusting pressure regulators or replacing safety devices should be left to a licensed plumber.
- Will the city fix supply-side pressure problems? The utility is responsible for mains and booster stations, but you should document times and contact them if multiple homes are affected—your plumber can also help coordinate.
For more related articles, see the Random Banging With No Water Running hub.