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Bathtub Leaking Into the Ceiling or Floor? How to Find the Source

A stain on the ceiling under an upstairs tub, or a soft floor next to a downstairs tub, means water is getting out somewhere. A bathtub can leak from the drain, the overflow, the faucet and valve, the caulk, or the tub itself. Call (951) 299-3473 any time.

Many tub leaks can be found with simple tests. When they cannot, our water leak detection in Murrieta team uses thermal imaging and moisture meters to find the spot before drywall is cut.

Where does a bathtub usually leak?

A bathtub usually leaks from 5 places: the drain gasket under the tub, the overflow gasket behind the plate, the faucet valve inside the wall, cracked or missing caulk and grout, or a crack in the tub itself. Drain and overflow leaks happen only when the tub is used. Valve leaks can drip all the time.

When it leaksLikely source
Only when the tub drainsDrain gasket or drain pipe joint
Only when the tub is filled highOverflow gasket
Only during showersCaulk, grout, spout or shower head arm
All the time, even with the tub offValve or supply pipe in the wall
Floor flexes or cracks near the tubCracked tub or failed tub base
Graphic of the five places a bathtub leaks and how to test each in a Murrieta home
Graphic of the five places a bathtub leaks and how to test each in a Murrieta home

How do you test each spot?

  1. Drain test: Close the stopper, fill 2 inches of water, and mark the level. Wait an hour. If it dropped, the stopper or drain gasket is leaking. Then pull the stopper and watch the ceiling below.
  2. Overflow test: Fill the tub above the overflow plate and let it drain through the overflow. A new drip below points to the overflow gasket.
  3. Shower test: Aim the shower only at the back wall for 10 minutes, then only at the tub ledge and corners. Water showing up after one of these points to caulk or grout there.
  4. Valve test: With all water off, check the meter. If the leak dial moves and the stain keeps growing, a pressure pipe or the valve is leaking.

Our water meter leak test guide shows how to read the dial.

Why do Murrieta tubs leak?

Many Murrieta homes from the late 1980s and 1990s, in Los Alamos Hills, Bear Creek and the streets around Historic Murrieta, still have their original tubs, drains and valves. Rubber gaskets dry out with age. Hard water from the local supply also builds scale on valve parts and wears them faster. Two-story homes put the tub right over a living room ceiling, so a small leak shows up fast.

Have a leak? Don’t wait for it to get worse.

Our technicians are standing by 24/7 with the equipment to find your leak fast. No unnecessary digging, no guesswork.

Can a tub leak cause mold?

Yes. A slow leak under a tub stays dark and damp, which is ideal for mold. You may notice a musty smell in the bathroom or the room below before you see a stain. Our guide on mold from a hidden water leak covers the signs.

What does it cost to find and fix?

Water leak detection in Murrieta usually costs about $200 to $550. Drain and overflow gaskets and caulk are small repairs. Valve and pipe repairs start from about $300 and depend on access. If the tub sits on a slab and the floor next to it is warm, the leak may be under the foundation instead. See our slab leak detection page for that.

For the full list of what we find and fix, start on our leak detection Murrieta CA home page.

Frequently asked questions

Why is my bathtub leaking through the ceiling?

The most common causes are a worn drain gasket, a failed overflow gasket, cracked caulk or grout, or a leaking valve inside the wall. A drain test and a shower test help tell them apart.

How do I know if my tub drain is leaking?

Fill 2 inches of water with the stopper closed, then pull the stopper and watch the ceiling or floor below. Water showing up while it drains points to the drain gasket or pipe joint.

Can I keep using a leaking bathtub?

Use another shower until it is fixed if you can. Each use adds water to the ceiling or floor, which raises the risk of mold and drywall damage.

How much does water leak detection cost in Murrieta?

Water leak detection in Murrieta usually costs about $200 to $550. Repairs start from about $300 depending on the fix.

Prices are approximate estimates for planning. Your final price depends on your property and is confirmed before work begins.

Ready to find your leak?

Our technicians are standing by 24/7 with the equipment to find your leak fast. No unnecessary digging, no guesswork.

Call Now — (951) 299-3473