Signs your shower pan is leaking

The most common signs of a leaking shower pan are water stains on the ceiling below the shower, damp or swollen baseboards next to it, a lingering musty smell, and grout at the base of the shower that stays dark long after it should be dry. Those same signs can come from other parts of the shower, though, so it pays to narrow down the source before tearing anything out.

Warning signs to look for

• Ceiling stains below the shower. On a second-floor bathroom, a brown ring or bubbling paint on the ceiling underneath is often the first sign.
• Damp or swollen baseboards and flooring just outside the shower, or along the wall behind it.
• A musty smell in the bathroom that doesn't clear when the room is aired out.
• Dark grout at the base of the shower that stays dark for a day or more after showering.
• Loose or cracked floor tiles, or tiles that sound hollow when tapped.
• Mold or mildew at the bottom of the walls or on the curb.

Other things that cause the same signs

Before blaming the pan, rule out the other usual suspects:

• The valve or supply lines inside the wall. These leak whether the shower is running or not if the line is under pressure.
• The drain connection under the floor.
• The shower door or glass, letting water out onto the bathroom floor.
• Cracked grout or failed caulk on the walls, at the curb or around the door.

A simple check you can do

Pay attention to when the water shows up. If the damage only appears after someone showers, the shower itself (pan, drain, grout, door) is a likely source. If it's there even when no one has showered, a pressurized supply line is more likely, and that's a call for a plumber. Stand outside the shower while it runs and watch the door and curb, too: water escaping onto the floor is a different and easier fix.

Whatever you find, take photos of the stains and note the dates. It helps whoever comes out to look.

What fixing a leaking pan involves

A shower pan sits under the mortar bed and tile, so it can't be patched from above. When the pan has failed, the lasting fix is a re-pan:

1. Remove the floor tile, mortar bed and old pan, plus the curb and lower wall tile as needed.
2. Check the framing and subfloor for water damage and repair it.
3. Install a new hot mop pan, up the walls, over the curb and clamped at the drain.
4. Flood test the new pan.
5. Rebuild the mortar bed and tile.

It's a bigger job than regrouting, which is why it's worth confirming the cause first. It's also a good moment to rethink the shower: a bench, a niche, a bigger footprint or a curbless entry.

Frequently asked questions

Can I keep using a shower with a leaking pan?

It's best not to. Each shower sends more water into the framing and subfloor, which can lead to rot, mold and damage to the ceiling below. Use another shower if you can until it's checked.

Will new grout or sealer fix a leaking pan?

No. Grout and sealer can help if the grout is the problem, but they can't fix a failed membrane under the mortar bed.

How do I know whether it's the pan or the plumbing?

Timing is the biggest clue: damage that appears only after showers points to the shower; damage that's there even when the shower hasn't run points to a pressurized supply line. When in doubt, have it looked at.

Think your shower is leaking? Call (949) 446-4413 and describe what you're seeing, or read about shower pan leak repair in Orange County.

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• What is a hot mop shower pan? November 11, 2026
• How a shower flood test works November 3, 2026

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