Signs of a Hidden Water Leak You Shouldn't Ignore

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Some leaks are loud. A burst pipe, a water heater that dumps everything on the garage floor, a toilet that overflows. Those you notice. The ones that cause the most trouble are often quiet. A slow drip behind a wall, a pinhole in a supply line or a shower pan that leaks a little every day. By the time you see it, the damage has been building for a while.

Here's how to spot a hidden leak early.

What Are the Most Common Signs of a Hidden Leak?

Things you can see:

• Water stains on ceilings or walls, often yellowish or brown rings
• Bubbling or peeling paint
• Warped, cupped or buckling floors
• Loose tile or cracked grout
• Spots or discoloration along baseboards
• Rust or corrosion around fixtures or under the water heater

Things you can smell:

• A musty, earthy odor in one room or cabinet

Things you can hear:

• Running or dripping water when everything is off

Things you can measure:

• A water bill that jumps with no change in use
• A water meter that moves when no water is being used
• Low water pressure

Where Do Hidden Leaks Usually Start?

• Under sinks: supply lines, drain connections and garbage disposals
• Behind toilets: supply lines and wax rings
• Showers and tubs: pans, valves and grout
• Behind the washer: supply hoses
• Dishwashers and ice makers: supply lines
• Water heaters: tanks, valves and connections
• Attics: water lines and AC condensate lines. See attic water in Texas summers
• Under the slab: supply or drain lines, especially in North Texas clay soils

How Can I Check My Home for a Hidden Leak?

Set aside an hour:

1. Check the meter. Turn off every faucet, appliance and irrigation system. Look at the leak indicator on your meter or note the reading. Wait an hour without using water. If it moved, water is going somewhere.
2. Check toilets. Put a few drops of food coloring in the tank. Wait 15 minutes without flushing. If color shows up in the bowl, the flapper is leaking.
3. Open every sink cabinet with a flashlight. Feel the bottom of the cabinet and the pipes for moisture.
4. Look at ceilings below bathrooms and under the attic.
5. Check behind the washer and fridge.
6. Look at the water heater for rust, drips or a wet pan.
7. Walk the yard for unusually soggy or green spots near the foundation.
8. Sniff around. Seriously. Your nose is a good leak detector.

What Should I Do If I Find One?

• Shut off water to the fixture or the main
• Take photos
• Call a plumber to repair the source
• If water has reached drywall, flooring or cabinets, call for a moisture assessment

Hidden leaks often mean wet materials you can't see. Moisture meters and thermal cameras show how far water traveled. Our guide on wet drywall: dry or replace explains what happens next.

Why Are Hidden Leaks Common in North Texas Homes?

A few local reasons. Many homes here have water lines and AC equipment in the attic, where a slow drip can soak insulation for weeks before a stain shows below. Most homes sit on slab foundations over expansive clay soil, which moves as it wets and dries and can stress pipes over time. And long, hot summers mean AC systems run nonstop, producing a steady stream of condensate that has to drain somewhere. Knowing your house's weak spots helps you check the right places.

Can Hidden Leaks Cause Mold?

Yes. A slow leak keeps materials damp for a long time, which is exactly what mold needs. If you smell mustiness or see spots, take it seriously.

How Can CMDR and G3 Help?

CMDR Restoration, our mitigation partner (licensed by TDLR, RCO #1801), can find and dry hidden moisture. G3 rebuilds what has to come out, from drywall and cabinets to flooring and tile. Learn more on our water damage page, or call (945) 300-9018.

Frequently Asked Questions

Keep learning: see our Water Damage page, read 5 Water Damage Myths We Hear All the Time, or read what homeowners say in our customer reviews.