This week

A ceiling stain under a wet room. Something above is leaking slowly.

A slow leak is not an emergency tonight, but every shower adds to it, and a stain that grows is a cavity that is staying wet.

What is probably happening

A failed tub or shower drain seal, a toilet wax ring, caulk at the tub edge, or a pinhole in a supply line above.
If the stain only appears after someone showers or flushes, it is a drain or seal. If it grows all the time, it is a supply line.
The drywall you can see is the bottom of a cavity that may have wet insulation and framing in it.

Do this in the next five minutes

Stop using the fixture above until it is found. Use another bathroom.
Mark the edge of the stain with a pencil and the date. Growth tells you the leak is live.
Run the fixtures above one at a time with someone watching the ceiling, to narrow it down.
Check the caulk at the tub or shower edge and the base of the toilet. Most slow ceiling stains start there.
Photograph the stain.

Do not

Do not paint the stain. It will come back and you lose the evidence.
Do not keep using the shower above because it 'only drips a little'.

Who to call

A licensed plumber

Finding and fixing the leak is plumbing. Only once it is stopped is there anything to dry or patch.

Also: Water damage. If the plumber opens the ceiling and finds wet insulation or framing, or the stain has been there for weeks. Questions for that call ›

Get a free shortlist The seven questions for this trade

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What it should cost

$150 to $4,700

Pipe leak repair, national range, average $500. The wide range is access: a leak in a ceiling costs more to reach than one under a sink.

Source: Angi, pipe leak repair cost, updated July 2026. View source

National published range, not a quote for your job. The full cost table for this trade is on the plumbing page.

Ask this contractor, on the phone, before anyone comes out

Tap each one as you ask it.

Will you find the leak before you quote the repair, and what does the diagnostic visit cost?
Is it a drain, a seal or a supply line?
Do you open the ceiling from below or the floor from above, and who patches it?
Should the cavity be moisture tested before it is closed?

End the call if

A quote to repipe the bathroom for a wax ring or caulk problem.
A ceiling patched the same visit with no look at the insulation above.

Insurance. This is the kind of loss insurers argue about. A sudden failure is covered; a leak that has been staining the ceiling for months is a gradual leak and usually excluded (Texas Department of Insurance).

Where this comes from

Not my problem, tap through instead Every water damage answer