Quick Answer:
If a toilet starts gurgling after a bathroom remodel, it most often means a vent or drain route was changed or blocked during the work. Start with a careful visual check of the remodel area for any capped vents or rerouted drains, then test the system by running a high-volume fixture (like a bathtub) to see if the gurgling gets worse. If the problem persists, a plumber is appropriate.
Why This Happens
Plumbing vents let air into drain pipes so water flows smoothly and traps keep sewer gas out. During a remodel, vents can be capped, blocked by new framing or drywall, or drain lines can be rerouted in ways that create air locks or slow flow. When a vent is restricted, the toilet can pull air through the trap as water drains and make a gurgling noise. Changes in how fixtures are connected can also cause pressure swings that produce bubbles or gurgles.
Step-by-Step What to Do
Step 1 — Inspect remodel areas
- Look where the contractor worked: behind walls, in closets, in the attic, and under sinks near the remodel. Inspect remodel areas for vent caps or rerouted drains.
- Check trim and new drywall for signs of a capped pipe or a sealed access panel that might hide a vent opening.
Step 2 — Check visible vent points
- From inside the attic or any crawl space, look along the vent lines that run to the roof. Don’t climb on the roof unless you are experienced and have fall protection.
- Confirm that vent pipes aren’t blocked by insulation or debris placed during the remodel.
Step 3 — Test with a high-volume fixture
- Run a bathtub or shower at full drain, or flush the toilet several times while someone watches the bowl for gurgling. Test by running a high-volume fixture to see if the noise increases when large volumes of water move through the system.
- If gurgling gets louder or occurs only when another fixture drains, that strongly suggests a vent or shared drain issue rather than a faulty toilet.
Step 4 — Check traps and clean-outs
- Make sure the trap seal isn’t broken (no unusual siphoning). Look at nearby clean-outs to see if they were disturbed or left loose during the remodel.
- Don’t remove traps or pipes unless you know how to reconnect them correctly.
Step 5 — Next steps if you find a suspected vent cap
- If you discover a capped or blocked vent inside a wall, leave the area capped until a professional evaluates the correct repair. Altering vents or cutting into walls can create code and safety issues.
- If no obvious cause is found, document what you checked and share that with a plumber to speed diagnosis.
For related situations, see Gurgling after installing vent device and Toilet bubbles after pressure change for more details on specific causes and tests.
What Not to Do
- Don’t assume remodel gurgling is settling—vent changes are common; a plumber is appropriate.
- Don’t cap or reopen vents yourself without understanding local code and vent routing.
- Don’t pour chemical drain cleaners into the system to “fix” gurgling; they won’t solve venting problems and can damage pipes.
- Don’t ignore repeated gurgling, slow drains, or sewer smells—these can lead to backups and bigger repairs.
When to Call a Professional
- Call a licensed plumber if the gurgling continues after your checks, if multiple fixtures are affected, or if you smell sewer gas.
- Hire a pro when you find a capped or altered vent or when repair requires cutting into finished walls or roof work.
- If drains back up or you notice sewage, call immediately—this is not a DIY fix.
Safety Notes
- Do not climb on roofs or into attics without proper safety gear and experience. Falls are a major hazard.
- Avoid exposure to sewage. Wear gloves and eye protection if you must inspect drains or clean-outs.
- If the remodel involved structural work, confirm any openings or access panels were closed safely before cutting into walls.
Common Homeowner Questions
- Is the gurgling dangerous?
Not usually immediately dangerous, but it can signal venting or sewer issues that may lead to backups or odors if left unchecked. - Could new drywall or tile work block a vent?
Yes—new framing, drywall, or boxed-in plumbing chases can accidentally seal vent openings or access points. - Will this fix itself over time?
No—don’t assume it will settle. If the gurgling is caused by vent changes, it’s unlikely to resolve without repair.