Quick Answer:

Air in the pipes after a shutoff can make drains “burp” when water returns. In most cases you can clear the noise by purging air at the highest fixtures, running water to reset traps, and then rechecking the drains after a short wait. If gurgling continues or you see slow drains across the house, call a plumber.

Why This Happens

When the main water supply is shut off and then turned back on, trapped air moves through the plumbing. That air can push through and displace water in P-traps, causing noisy burps or gurgles as the system re-pressurizes. Usually it’s temporary; persistent gurgling can mean a venting issue or a partial blockage in the drain or sewer line.

Step-by-Step What to Do

1. Purge air at the highest fixtures

Start at the highest points in the house (top-floor sinks, showers, or an upstairs hose bib). Open those fixtures fully until the flow is steady and free of sputtering. This gives trapped air a path out of the system instead of down into the traps.

2. Open lower fixtures and run water to stabilize traps

After the highest fixtures flow smoothly, open lower sinks, tubs, and outdoor spigots. Run each for 20–30 seconds. Flush toilets once or twice. The goal is to let water refill each P-trap so air doesn’t remain in place and cause gurgling.

3. Check for gurgles that persist after purging

Listen at each drain while water runs. If one fixture still gurgles after purging, try running water in an adjacent fixture (for example, run the bathroom sink while flushing the toilet). Persistent gurgling in one location can point to a vent problem or a localized clog.

4. Confirm there are no widespread slow-drain symptoms

Test multiple drains around the house. If only the one that was purged burps and then clears, it was likely just air. If several drains are slow or toilets are backing up, that suggests a larger drain or sewer issue.

5. Retest after 10 minutes

Wait about 10 minutes and check the affected drains again. Temporary air noises often stop after a short settle period. If the burping returns or slow drainage appears during this retest, move to the “When to Call a Professional” steps below.

What Not to Do

• Do not open cleanouts unnecessarily; that can make a mess and introduce sewer gas into the home.
• Don’t assume a sewer issue if the problem resolves after purging—air-related burps often clear on their own.
• Don’t pour strong chemical drain cleaners into fixtures to chase air noises; they won’t help air escaping the pipes and can be hazardous.

When to Call a Professional

Call a plumber if you see any of the following after purging and retesting:

• Gurgling or bubbling that continues after multiple purges and the 10-minute retest.
• Multiple slow drains, toilets backing up, or a persistent sewage smell—signs of a partial or full blockage.
• Recurring air noises tied to a single fixture that don’t respond to running water.

If the problem only happens when you run the garbage disposal or appears right after using soap, mention that to the plumber — those details help diagnose grease or trap-related issues faster.

Safety Notes

• Wear gloves and eye protection if you need to catch drips or check under sinks.
• Have a bucket and towels ready before loosening any plumbing trap; even small repairs can spill water.
• Avoid entering confined spaces or digging around sewer lines yourself. Those tasks require trained professionals and proper equipment.

Common Homeowner Questions

• Why did the burping start right after the water was shut off?
  Air entered the pipes while pressure was low; it moved when pressure returned and escaped through traps as noise.
• How long should I wait for noises to stop?
  Give it about 10 minutes after purging and running water; most air-related noises stop within that time.
• Could this damage my plumbing?
  Short-term air burps don’t harm pipes. Persistent issues could indicate a vent or blockage problem that should be inspected.