5 Signs of a Hidden Water Leak

Three months ago, I got a call from a panicked homeowner in Battle Ground. "My water bill jumped from $80 to $240, and I have no idea why!" When I arrived, everything looked fine—no visible drips, no wet spots. But my thermal camera told a different story: a pinhole leak in a copper pipe behind their master bathroom was dumping 3 gallons per hour into their wall cavity. The damage? $6,800. The detection fee? $300. Here's how to catch these nightmare leaks before they catch you.

Hidden leaks don't announce themselves like a burst pipe. They whisper. Your job is learning their language before your home starts speaking in mold and rot.

1. Your Water Bill Jumped for No Reason

This is the #1 red flag I see. If your bill suddenly jumps 30-50% and you haven't filled a pool or had guests staying over, you've got a leak somewhere. In Vancouver's water district, anything over $120/month for a typical 3-bedroom home warrants investigation. Pro tip: Check your usage in CCF (hundreds of cubic feet) on your bill—if it's doubled, you're losing serious water.

2. That Musty Smell (Especially in SW Washington)

Our climate here is already humid, so people often dismiss musty odors as "just the Pacific Northwest." Wrong. If you smell mildew in a bedroom closet or notice black spots on baseboards away from bathrooms, that's a leak talking. I found a slab leak under a Camas home last year because the owner said their master bedroom "smelled like a basement." Trust your nose.

3. Ceiling or Wall Stains You Can't Explain

See a yellow-brown stain spreading on your ceiling? That's water damage, period. Even if it's dry to the touch, the leak might be intermittent or slow-dripping only when pressure spikes (like when neighbors use water). Don't wait for it to get "worse"—it already is worse behind that drywall.

4. You Hear Water Running (But Nothing's On)

Late at night when the house is quiet, walk around and listen. Hear a faint hissing or trickling? That's not normal. I've traced leaks just by following the sound with my ear against the wall. Sounds low-tech, but it works—and it's free for you to try before calling me.

5. The Water Meter Test (Do This Right Now)

Here's your homework: Turn off every faucet, shower, washer, dishwasher, and ice maker. Go to your water meter (usually in a ground-level box near the street). See that little triangle or dial? If it's moving at all, you've got a leak. This test has a 100% accuracy rate and takes 3 minutes.

What to Do If You Suspect a Leak

First: don't panic and start tearing open walls. I've seen homeowners cause $3,000 in drywall damage trying to find a $200 leak. Call a professional with leak detection equipment—we use acoustic sensors and thermal cameras that pinpoint leaks within inches without demolition.

Second: Turn off your main water supply if the leak seems active (wet spots, active dripping sounds). The shut-off valve is usually near your water heater or where the main line enters your house.

Third: Document everything for insurance. Take photos of stains, water bills, and meter readings. Many homeowners' policies cover leak detection and repairs if you catch it early and can prove it's sudden (not long-term neglect).

The Battle Ground Family's $6,500 Lesson

Remember that family I mentioned? They waited 3 months before calling me, thinking the high bill was a "meter error." By the time I found the pinhole leak, they had mold remediation costs, drywall replacement, and structural drying bills. If they'd called after month one when the bill first spiked, the total damage would've been under $800.

My honest advice: If any of these 5 signs show up, spend the $200-$400 on professional detection immediately. It's the cheapest insurance you'll ever buy.

Frequently Asked Questions