Quick Answer:
Hearing bangs in your plumbing after a storm, with no water running, often points to pressure surges coming from the supply side or to components in the home reacting to sudden pressure changes. Note the exact times and locations of the bangs, listen near the water heater and the main water entry to localize the sound, and check whether neighbors hear it too. If the pattern suggests a supply-side pressure event, a licensed plumber can safely test and confirm the cause.
Why This Happens
Storms can change how the municipal water system behaves: crews may start or stop pumps, a main can break and re-pressurize the line, or valves can cycle. Those sudden pressure changes travel down the supply line into your house and create sharp, banging sounds as pipes or control devices snap back into place.
Inside the home, the noise can come from:
- Pressure regulator or service valve cycling under a surge.
- Water heater tanks and connected piping shifting or expanding.
- Backflow prevention assemblies or check valves closing suddenly — sometimes seen after new equipment is added, similar to reports of Random hammer after installing backflow.
- Pipes contracting or moving in cold weather, a pattern homeowners sometimes compare to Random banging during cold weather.
Step-by-Step What to Do
1. Note the time of each bang
- Write down the exact time each noise happens. Small patterns (every 15–30 minutes, or only around certain hours) are important to identify.
2. See if neighbors hear it
- Ask one or two nearby neighbors whether they hear the same noise at the same times. If they do, the cause is likely on the supply side.
- Contacting the local water utility to report a timed pattern can help; they can confirm if there are pump cycles or main repairs.
3. Localize the sound in your house
- Listen near the main water entry and around the water heater while the noise occurs. If the banging is loudest there, it suggests service-line pressure changes or a pressure-regulating device.
- Move slowly through the house to identify which wall or pipe run seems to vibrate.
4. Check fixtures and appliances
- Confirm no toilets are running, no irrigation is scheduled, and no appliances are cycling (hot water recirculators, boilers, or well pumps if present).
- If a fixture is cycling intermittently, fix that first (for example, replace a toilet fill valve).
5. Record and compare
- Keep a short log for a day or two with times and notes about weather, municipal work, or neighbor reports. This makes it easier for a plumber or utility technician to diagnose the issue.
6. When to call for a professional check
- If the bangs keep happening with no fixtures running, or you notice pressure-related problems (leaks, dripping, or noisy valves), have a plumber evaluate pressure control components like the PRV, backflow device, expansion tank, and the service connection.
What Not to Do
- Don’t start opening walls to chase the sound yourself; this can create unnecessary damage.
- Don’t disable safety devices (pressure relief valves, backflow preventers, or expansion tanks) to stop the noise.
- If bangs continue with no fixtures running, have a plumber evaluate pressure control components rather than trying to bypass them.
When to Call a Professional
- Call a licensed plumber if the banging is frequent, occurs at unpredictable times, or coincides with leaks, visible pipe movement, or pressure loss at fixtures.
- Also call if you record a regular pattern that points to supply-side pressure events; a plumber can safely test the incoming pressure and inspect the PRV, expansion tank, and backflow or check valve assemblies.
- If you’re unsure whether the water utility or your own equipment is at fault, a plumber can coordinate with the utility and document findings.
Safety Notes
- Do not tamper with your water heater’s safety valves. If you suspect the heater is making the noise, shut off its power source (electricity or gas) and call a professional if you see leaks or feel excessive heat.
- Only shut off the main water valve if there is an active leak or flood. Know where that valve is before an emergency.
- Let a licensed plumber handle pressure adjustments, backflow devices, or service-line work. Those systems protect your home and the public supply and must not be disabled.
Common Homeowner Questions
- Q: Could the city be causing the bangs?
A: Yes — pump cycling or repairs on the mains after storms often cause pressure surges that reach many homes. - Q: Is this danger to my pipes?
A: Occasional bangs are not usually an emergency, but repeated high-pressure events can stress fittings and seals — have it checked if it continues. - Q: Can I fix it myself?
A: You can log times and localize the sound, but for pressure control parts and service-line issues, hire a plumber to avoid safety risks.
For more related articles, see the Random Banging With No Water Running hub.