10 Signs of a Hidden Water Leak and When to Call

1. A musty or earthy smell

A damp, basement-like smell in one room, a closet or under a sink often means wet materials nearby. It is usually stronger when the heat is on or the room has been closed up.

2. A water bill that keeps climbing

If your bill jumps and your habits have not changed, check it against the same month last year. A steady rise is a classic sign of a hidden leak.

3. Stains on ceilings or walls

Yellow or brown rings, often with a darker edge, show where water dried and came back. Watch ceilings below bathrooms and laundry rooms.

4. Bubbling or peeling paint

Water behind paint pushes it away from the wall. Bubbles near baseboards or window corners are common.

5. Soft, warped or lifting floors

Hardwood that cups, laminate that swells at the seams, or vinyl that lifts can mean water underneath. Soft spots near toilets are a red flag.

6. The sound of running water

Listen when the house is quiet and nothing is running. A hiss or trickle inside a wall is never normal.

7. Mold spots in odd places

Small black or green spots on a wall, behind furniture or inside a cabinet usually mean moisture is feeding them from behind.

8. A warm spot on the floor

In homes with radiant heat or hot water lines in the slab, a leak can make one area of floor feel warm.

9. Low water pressure

If pressure drops across the whole house, water may be escaping before it reaches your taps.

10. Wet soil or extra-green grass

A soggy patch in the yard, even in dry weather, can mean the main water line is leaking underground.

This simple test tells you if water is leaking anywhere in your plumbing.

1. Turn off every tap, appliance and irrigation system. Make sure no toilets are refilling.
2. Find your water meter. It is often in a box near the street or sidewalk.
3. Look for the small leak indicator, often a little triangle or dial. Write down the numbers.
4. Wait 15 minutes without using any water. Then check again.
5. If the indicator moved or the numbers changed, you have a leak.

Next, shut off your home's main valve and check the meter again. If it still moves, the leak may be in the line between the meter and the house. If it stops, the leak is inside your home.

Toilet check: put a few drops of food coloring in the toilet tank. If color shows up in the bowl within 15 minutes without flushing, the flapper is leaking.

In Western Washington, cool damp winters cause plenty of condensation. Water on windows, cold pipes or outside walls is not always a leak.

If you are not sure, a moisture reading tells the difference fast.

• Behind and under toilets: worn wax rings and supply lines.
• Under sinks: loose drain joints and old supply hoses.
• Behind the fridge: cracked ice maker lines.
• Under dishwashers: drain hoses and door seals. See appliance leaks.
• Showers: failed grout, caulk and valve seals.
• Water heaters: tank corrosion and relief valves. See water heater leaks.
• Older homes: aging pipes inside walls and crawl spaces.

Opening walls to hunt for a leak is slow and expensive. Our technicians use tools that see through surfaces:

• Thermal cameras show cool, wet areas behind drywall and ceilings.
• Moisture meters confirm how wet a material is and how far the water spread.
• Acoustic tools help pinpoint the sound of a pressurized leak.

Once we know where the water is, we open only what is needed. Then a plumber repairs the pipe, and we dry and restore the area. Read how long drying takes.

A slow leak can soak a subfloor, rot framing and grow mold long before you see a drop. Mold can start in 24 to 48 hours on wet materials. Many insurance policies also treat long-term leaks differently from sudden ones, so finding it early can matter for coverage. Read what insurance usually covers.

We find and dry hidden leaks across Kirkland and nearby areas like Houghton, Clyde Hill and Medina.