What it usually looks like
- The bill is noticeably higher than the same month last year with no change in household habits
- The water meter's leak indicator turns with every fixture in the house off
- A toilet occasionally hisses, refills on its own, or has a faint ripple in the bowl
- One patch of lawn is greener, softer or mossier than the rest
- The water heater runs more than it should or the hot side of the meter test moves
- The crawlspace smells damp or shows standing water that has no obvious source
Likely causes, most common first
A toilet flapper or fill valve leaking into the bowl
The flapper at the bottom of the tank hardens and warps, and water trickles into the bowl constantly. The fill valve tops the tank off every few minutes. There is no puddle because the water goes down the drain. This single cause explains the majority of mystery bills, and a house with three toilets has three chances for it.
An underground leak on the service line
The line from the meter to the house runs through soil that drains well in summer and swallows a leak without a trace. Old polyethylene and galvanized service lines fail at fittings, and tree roots and settling do the rest. The only evidence may be the meter moving with the house shut off.
A leak under the house or slab
A pinhole in a copper line in the crawlspace can spray a fine mist for months into gravel and insulation. On slab homes, a leak under the floor shows up as a warm spot or a bill, nothing more.
Irrigation or hose bib left on
A zone valve stuck open, a drip line cut by a shovel, or a hose bib with a hose attached and a leaking sprayer can move a surprising amount of water. Irrigation leaks are seasonal and will match a summer bill spike.
Water softener or filter stuck in regeneration
A softener or backwashing filter that fails to finish its cycle runs water to the drain continuously. If you have treatment equipment and the bill climbed, listen for water running at the unit.
A faulty meter or a misread
This is the least likely answer, but a meter can be read wrong or estimated for a cycle. Compare the meter face to the bill before assuming the worst.
Safe things to check yourself first
- Put a few drops of food coloring in each toilet tank, wait fifteen minutes without flushing, and look for color in the bowl
- Turn off every fixture, then watch the small triangle or dial on the water meter for a full two minutes; any movement is a leak
- Close the main shutoff at the house and check the meter again; if it still moves, the leak is in the service line
- Walk the route from the meter to the house looking for soft ground, lush grass or standing water
- Check the irrigation controller and manually confirm each zone shuts off
- Listen in a quiet house for the faint hiss of water moving
Stop and call if
- The meter moves with the house's main valve closed, which means the underground line is leaking
- You find standing water in the crawlspace or a wet spot on a slab floor
- A ceiling or wall shows a stain, bubbling paint or softness
- The meter is spinning fast enough to read in gallons per minute, not a slow creep
How we diagnose and fix it
- Run a meter test with the house isolated in sections to put the leak on the service line, the house supply, or a fixture
- Check every toilet with dye and inspect fill valves and flappers, replacing worn parts on the spot
- Use acoustic listening and pressure testing to locate an underground or crawlspace leak without digging the whole yard
- Repair or replace the failed section of service line, or run a new line when the old one has multiple failures
- Install a Flo by Moen smart shutoff for homes that sit empty, so the next leak is caught and stopped automatically
- Document what we found and fixed so you can request a leak adjustment from your water district
Around Kitsap, Pierce and Mason counties
Long service lines are the signature leak in our area. A home at the end of a gravel driveway in Olalla, Burley or out on the Key Peninsula may have several hundred feet of pipe between the meter and the house, and a lot of it is 1970s poly with barbed fittings. Summer is when those leaks hide best, because the glacial till soaks up water and the surface stays dry. Several local districts, including West Sound and the City of Port Orchard, will consider a one-time bill adjustment with proof of repair, and we provide that paperwork.
Questions people ask
How much water can a running toilet really waste?
A badly leaking flapper can pass more than a hundred gallons a day, and a stuck fill valve far more. Over a billing cycle that adds up to thousands of gallons with no sound you would notice.
The meter is moving but every faucet and toilet is off. What now?
Close the main valve at the house and check again. If the meter stops, the leak is inside; if it keeps moving, the leak is between the meter and the house, underground.
Can you find an underground leak without digging up the yard?
Usually. Acoustic equipment and pressure isolation narrow it to a few feet. On a long rural line with multiple old fittings, replacing the whole run is sometimes cheaper than chasing leaks one at a time.
Will the water district reduce my bill?
Many local districts offer a leak adjustment once per period if you show the leak was repaired. Ask your district and keep our invoice.
Could the water heater be the cause?
A leaking tank drains onto the floor, so it is rarely invisible. A relief valve piped outside, though, can discharge for months unnoticed. Check where that pipe ends.
Is a smart shutoff worth it for a vacation home?
For a cabin on Hood Canal or a rental that sits empty for weeks, yes. It watches flow continuously and closes the valve on a leak, which can be the difference between a repair and a restoration claim.