Key takeaways
- Meter moving with every fixture closed and the house main open: water is leaving somewhere.
- Meter still moving with the house main closed: the leak is on the buried service line outside.
- Meter stops when the house main closes: the leak is inside the house, on the supply system or irrigation.
- Isolating hot from cold at the water heater narrows an interior leak further.
Why this matters before anyone digs or cuts
An exterior leak is found with a ground microphone and fixed with an excavator. An interior leak is found with a thermal camera and an acoustic sensor and fixed by a plumber through one opening in a wall. Guessing wrong means a trench for a leak that's in the crawlspace, or a hole in a wall for a leak that's under the driveway. The meter test prevents both, and it takes five minutes with no tools.
Test one: is water leaving?
Close every fixture: taps, toilets, ice maker, irrigation, hoses, water softener. Find the meter at the street and watch the low-flow indicator, the small triangle, star or dial, for two minutes. Movement means water is leaving the system somewhere.
Test two: which side of the house shutoff?
Close the house's main shutoff, where the service line enters the building. Watch the indicator again. If it keeps moving, the leak is between the meter and the shutoff: the buried service line, or an irrigation or outbuilding branch that tees off before the house. If it stops, the leak is on the house side of the shutoff: the interior supply system.
If irrigation tees off before the house shutoff, isolate it separately at its own valve so it isn't mistaken for the service line.
Test three: hot or cold?
For an interior leak, the water heater has a cold inlet valve. Closing it isolates the hot side of the house from the cold. If the water heater's pressure relief or a gauge on a hot tap shows the hot side losing pressure with the inlet closed, the leak is on a hot line. Hot-side leaks also leave a warm trail a thermal camera can read through drywall or a slab, which makes them the easiest interior leaks to pinpoint.
What happens next
Outside: an acoustic locate along the buried line, one excavation at the break, repair or replacement with our own equipment. Inside: tracing and listening along the supply lines, thermal imaging and moisture mapping, one opening at the mark, and a repair by our licensed plumbers with the wall patched afterward. Both are one call to the same company.
Written by the crew at 360 Leak Finders
We locate, excavate and repair buried water lines and exterior drains across Kitsap County, 24 hours a day. If this guide raised a question about your property, call (206) 354-9906.