Shower Pan Leak? Signs, Simple Tests and Fixes for Arlington Homes

A shower pan is the waterproof layer under the tile floor of a shower. When it fails, water soaks into the floor, the wall or the slab every time someone showers. The first signs are often stains on the floor outside the shower, loose tiles or a musty smell. Many Arlington homes built in the 1970s to 1990s still have their original tiled showers, so pan leaks are common. If you see the signs, call (817) 285-5426 for leak detection.

What is a shower pan leak?

A shower pan leak happens when water gets past the tile and grout and then through the liner below it. In older showers that liner is often a sheet of vinyl or lead. Over time it can crack, tear or come loose at the drain. The water then flows under the tile and out to the floor, the wall or the subfloor.

Not every shower leak is a pan leak. The drain, the valve in the wall, the shower arm and the grout or caulk can all leak too. Testing is the only way to know.

What are the signs of a shower pan leak?

Watch for water stains or damp carpet next to the shower, warped baseboards, loose or cracked floor tiles, dark grout that never dries, a musty smell, and mold at the bottom of the wall outside the shower. On a second floor, a stain on the ceiling below the shower is a common sign.

• Damp or stained flooring just outside the shower
• Tiles that move or sound hollow when you tap them
• Grout that stays dark long after a shower
• Peeling paint or soft drywall on the wall behind or beside the shower
• A musty smell in the bathroom or the next room

For other ways a leak shows up inside walls, see our guide to a leak in a wall or ceiling and the musty smell of a hidden leak.

How can I test my shower for a leak?

Run three simple tests on different days. A flood test checks the pan: plug the drain and fill the shower floor with about an inch of water for a few hours. A spray test checks the walls and door. A valve test checks the pipes in the wall with the water off at the shower but on in the house. Watch for new damp spots after each one.

1. Pan test. Cover the drain with tape or a test plug, add an inch of water and mark the level. If the level drops or the floor outside gets wet, the pan or drain may be leaking.
2. Wall and door test. Spray the tile walls and the door seal for 10 minutes without water reaching the floor drain area. Look for damp spots outside.
3. Valve and pipe test. With the shower off, watch the water meter for 15 minutes. If it moves, a pipe may be leaking. Our high water bill guide shows how to read the meter.

Do not leave a pan test full if water is reaching a finished ceiling below. Drain it and call for help.

Can a shower pan leak cause a slab leak?

No, but it can look like one. A shower pan leak is drain water from use. A slab leak is a pressurized pipe leaking under the floor all the time. A pan leak only adds water when the shower runs. Both can leave damp floors near a bathroom, so a meter test and a pressure test help tell them apart.

If the water meter moves with every tap off, read our guide to slab leak signs in Arlington or book slab leak detection.

How is a shower pan leak fixed?

A small grout or caulk gap can be cleaned and resealed. A failed drain gasket can sometimes be replaced from above. A torn or failed pan usually means taking out the shower floor tile, replacing the liner and re-tiling. A leaking valve or pipe is fixed through the wall, often from the back side or through a small access panel.

Finding the exact source first keeps the repair small. A moisture meter and a thermal camera can show where water travels without tearing out tile.

How much does leak detection cost in Arlington?

A basic leak detection visit in Arlington usually costs $150 to $400. If the leak is under the slab, slab leak detection runs about $250 to $600. You get the price before work starts.

General estimates for Arlington, TX in 2026. Your exact price is confirmed before any work begins.