Quick Answer:
Shortly after winterizing and then reopening your plumbing, gurgling is usually caused by air trapped in the lines or by venting that was closed or blocked during shutdown. After winterization, ensure all vents are open and fixtures are run slowly to clear air. If the noise continues, especially across multiple fixtures or with slow drains, get a plumber to check the venting and traps.
Why This Happens
During winterization you may have drained lines, capped vents, or closed attic access points. When you put the system back into service, pockets of air can get trapped in lines or in high points of the plumbing. That trapped air moves when water flows and pulls or pushes through nearby traps, which makes a gurgling sound.
Common patterns you might notice include Toilet gurgles when washer drains or Toilet bubbles when bathtub drains. Those patterns are signs that air or partial vent blockage is changing how water flows and how traps refill.
Step-by-Step What to Do
Step 1 — Start with the vents
- Go to the roof or attic access point and visually confirm that the plumbing vent(s) are open and not capped, crushed, or iced over.
- After winterization, ensure all vents are open and fixtures are run slowly to clear air — this is often enough to stop gurgling.
Step 2 — Run fixtures slowly, one at a time
- Open cold and hot taps and let water run at a steady, moderate flow to push trapped air out of the lines.
- Flush toilets once, then again after a minute. Run tubs and sinks for a few minutes to displace air pockets.
Step 3 — Check traps and drains
- Look under sinks and around floor drains for dry or empty traps (they can happen if drains were drained for winter). Pour a cup of water into each trap to reseal it if needed.
- If a single fixture gurgles only when another fixture drains, that points to a venting or air movement issue rather than a localized clog.
Step 4 — Test and narrow the problem
- After running fixtures, test: flush the toilet while someone runs a sink or the washer. Note whether gurgling is isolated or widespread.
- Document which fixtures cause the sound and whether there is slow drainage or odors.
Step 5 — Next steps if it persists
- If gurgling continues, try to clear any visible blockages in roof vent openings (carefully), then retest.
- If you can’t verify venting or the problem affects multiple fixtures or causes backups, call a licensed plumber.
What Not to Do
- Don’t leave winterized vents blocked—this causes gurgling and can prevent proper air flow through the system.
- If you can’t verify venting, a plumber is appropriate — don’t keep guessing or making risky roof climbs alone.
- Don’t pour aggressive chemical drain cleaners into a system you’ve just reactivated; they won’t fix venting or air issues and can damage pipes or fixtures.
- Don’t seal or cap vents to stop noise; that will make venting worse and increase the chance of sewer-gas odor or slow drains.
When to Call a Professional
- Gurgling continues after you’ve confirmed vents are open and you’ve run fixtures slowly to clear air.
- Multiple fixtures gurgle, drains are slow, or there is sewage smell or any backing up of water.
- You cannot safely access roof vents or attic spaces to verify vent condition.
- A plumber can run a proper vent stack inspection, camera the lines if needed, and safely restore normal airflow.
Safety Notes
- Be careful on the roof: use a sturdy ladder, proper footwear, and a spotter. If you’re uncomfortable, hire a pro.
- Turn off water at the main if you disconnect anything or if a leak appears while testing.
- Avoid entering confined spaces like crawlspaces without ventilation and a partner present.
Common Homeowner Questions
- Q: Is the gurgling an emergency?
A: Not usually; it often signals trapped air or venting issues, but call a plumber if it persists or if there is backup or odor. - Q: Can I fix this myself?
A: Yes for simple cases: open vents, run fixtures slowly, and refill traps. If you can’t access vents or the problem is widespread, call a pro. - Q: How long will it take to stop?
A: Often a few minutes to a few hours after running fixtures; persistent gurgling beyond that needs professional inspection.