Quick Answer:
If you hear banging after curb stop work even when no water is being used, the most likely causes are supply-side pressure changes or a loose fitting that responds to pressure swings. Note the exact times the bangs happen, listen near the water heater or the main entry to the house to localize the sound, and compare notes with neighbors or the local utility. If the pattern suggests a supply-side pressure issue, a plumber can safely confirm the cause and adjust pressure controls.
Why This Happens
Work on the curb stop or nearby main can change how pressure moves through the supply line. Sudden shifts in pressure or slow pressure surges can make pipes move or fittings pulse, which sounds like banging. Sometimes the problem appears only at specific times—during valve operations by the utility, hydrant flushing, or when neighbors run large amounts of water—so the noise can be linked to external supply activity. If the banging lines up with those events it may be a case of Banging only during pressure surges. If the knocking continues while all fixtures are off, the cause may be a pressure-control device or an arrestor that is not functioning correctly.
Step-by-Step What to Do
1. Record each event
- Write down the time and how long each bang lasts. Even a simple log for 24–48 hours helps identify patterns.
2. Check for outside or neighbor activity
- Ask neighbors whether they hear it or if they were using water at those times. Note whether the noise lines up with morning or evening peaks, street repairs, or hydrant flushing.
3. Localize the sound
- Listen at likely sources: the water heater, the main water entry, and near visible piping. Standing next to the heater and the main entry point helps tell whether the surge is upstream or inside the home.
- If the knocks occur with no taps or appliances running, this is often described as **Noise with no fixtures running** and points more to supply-side pressure control parts.
4. Confirm fixtures are truly off
- Double-check all taps, appliances (ice makers, irrigation controllers, boilers), and automatic systems so you can be confident the home isn’t creating the pressure change.
5. Note any recent work or changes
- Keep a record of when the curb stop work happened and whether the noise started immediately afterward. Share that information with a plumber or your utility when you call.
6. Simple visible checks (no disassembly)
- Look for obvious loose clamps or unsecured piping in accessible areas. Do not remove covers or tamper with valves. If you see movement when the bang occurs, note where it is for the professional.
What Not to Do
- Do not start opening walls to chase the sound. That risks damaging finishes and hiding the real source.
- Do not disable or bypass safety devices such as pressure relief valves, expansion tanks, or pressure-reducing valves.
- Don’t try to take apart pressure-control devices if you are not trained; if bangs continue with no fixtures running, have a plumber evaluate pressure control components rather than attempting repairs yourself.
When to Call a Professional
Contact a licensed plumber if any of the following are true:
- You can’t localize the noise or it seems to come from inside the walls and persists after basic checks.
- The bangs occur at times that point to supply-side changes (after curb stop work, during neighborhood water use, or during utility operations). In that case a plumber can safely test pressure at the main, check the pressure-reducing valve, and coordinate with the utility if needed.
- You see water leaks, hear metal scraping or loud uncontrolled hammering, or notice fluctuating household water pressure.
A plumber can place a pressure gauge on the service, test for surges, inspect the curb stop and PRV, and recommend or install arrestors or a pressure-regulating device if needed. This approach confirms the cause without risky homeowner repairs.
Safety Notes
- Turn off water only if you know where the main shutoff is and how to operate it; shutting the water off improperly can cause service interruptions for you and neighbors.
- Avoid adjusting or removing pressure relief valves, expansion tanks, or pressure regulators—these protect the system and your appliances.
- If you suspect a gas- or electrical-related vibration that coincides with the banging, stop inspections and call a professional immediately.
Common Homeowner Questions
- What if the banging only happens at night? Short answer: Note timing—night occurrences often point to timed irrigation, overnight utility work, or pressure fluctuations when demand drops.
- Can I fix a pressure regulator myself? Short answer: Not recommended—adjusting or replacing a PRV without experience can cause higher system pressure and damage; have a plumber handle it.
- Will the utility fix supply-side issues? Short answer: If the problem is in the public main or curb stop, the utility may investigate, but a plumber can confirm the location and coordinate with them.
For more related articles, see the Random Banging With No Water Running hub.