First, read the bill properly
Before blaming a leak, look at how your water usage is presented. Utility bills may show use in gallons or in hundred-cubic-feet units (often written as CCF). One CCF is about 748 gallons, which is why a number can look small and still mean a lot of water. Compare the current period with the same months last year, not the month before. Mesa summers push irrigation and cooling use up sharply, and last July is a fairer yardstick than last April.
A bill that has climbed with no change in habits, and no seasonal explanation, is worth testing. A single high bill is a prompt, not a verdict.
The meter test, step by step
- Find the meter box.It is usually a ground-level box with a lid near the curb or at the property line in the front yard. Some homes have it near the side or in a landscaped bed.
- Open it safely.Never put your fingers under the lid first. Meter boxes are a favorite hiding place for scorpions, spiders and sometimes snakes. Use a long screwdriver or meter key to lift the lid, look in with a flashlight and step back for a moment.
- Turn off everything that uses water.All taps, the dishwasher, washer, ice maker, irrigation controller and any evaporative cooler or pool auto-fill. Make sure no one flushes a toilet.
- Look at the leak indicator.Most meters have a small triangle, star or gear that spins when even a trickle moves through. If it is turning, water is moving.
- Take a reading and wait.Photograph the register and note the time. Wait thirty to sixty minutes with everything still off, then photograph it again.
- Compare.If the number changed or the indicator never stopped, you have a leak somewhere past the meter.
Reading the result
| What the meter does | What it probably means | Next step |
|---|---|---|
| Stays still, reading unchanged | No continuous leak now. The extra usage may be seasonal, intermittent or an irrigation schedule | Check the irrigation program and look at the next bill |
| Indicator turns slowly, reading creeps | A small, steady leak, such as a toilet flapper or a pinhole | Do the toilet dye test, then the main-valve test below |
| Indicator spins quickly | A significant leak: a broken line, a stuck valve or a failed fitting | Shut off the main and call, especially if the floor is damp |
Where is the leak? The main-valve test
If the meter is moving, one more step helps place the leak before you phone anyone. Locate the main shutoff valve at the house, usually on the front wall near a hose bib, in the garage or at the utility corner, and close it fully.
- The meter stops. The leak is inside the house, on the side of the valve that was just closed off. That includes lines under the slab, in the walls, at fixtures and at the water heater.
- The meter keeps moving. The leak is on the line between the meter and the house valve, outside the building. This is a service line problem, not a slab leak, and it is excavated rather than cut out of the floor.
Open the valve again before you leave it, so the household has water. It also helps to turn the main off for a few hours with the meter box closed and see if the water pressure at the heater changes; a simple observation, but the details help when you describe things on the phone.
Ruling out the cheap culprits
Before the leak moves up to “possibly under the slab,” look through the shortlist: the toilets (dye test), irrigation valves, a pool auto-fill, the evaporative cooler float, the water softener and the water heater relief drain. Our guide to the signs of a slab leak walks through each one and what it looks like.
What to do with a positive result
Take your photos of the meter and the dates. Note how fast it moved and whether the main-valve test stopped it. Then ask a professional to pinpoint the leak. It is also a good idea to tell your insurance company early; our insurance claims guide explains what documentation helps. Many utilities will not credit a bill for a private leak, though policies vary, so ask your provider what, if anything, applies.
If you would rather have someone check the numbers with you, SlabGuard’s Mesa team can talk through your readings, and slab leak testing in Mesa is a phone call away when the result is clear.
Questions people ask
My meter indicator moves a little even when everything is off. Is that normal?
A steadily turning indicator means water is flowing. Occasionally a softener or an icemaker will cycle, so confirm those are off. If the indicator still turns, treat it as a leak.
How long should I wait during the test?
Thirty to sixty minutes is a good window for slow leaks. A fast leak shows up in minutes.
Does a moving meter prove the leak is under the slab?
No. It proves water is escaping somewhere on your side of the meter. The main-valve test and the other checks narrow it down.
Will the utility fix a leak on my side of the meter?
Generally the property owner is responsible for lines from the meter to the home. Ask your water provider for specifics.
Last updated October 16, 2026. This page offers general information to help you understand and describe a problem; it is not a diagnosis of your home. Only an on-site inspection can confirm a leak or the right repair.