The Water Meter Leak Test: Ten Minutes, No Tools

A slab leak hides under concrete, but the water it loses still passes through the meter. That makes the meter the cheapest leak detector you own. This test takes about ten minutes and tells you whether a leak exists. The second part tells you roughly where.

Before you start

You need the meter, a phone to take a photo, and a few minutes when nobody in the house will use water.

• Turn off every faucet and shower.
• Make sure the dishwasher, washing machine and ice maker aren't running.
• Turn off the irrigation controller, or set it so no zone runs during the test.
• If you have a water softener, make sure it isn't regenerating.
• Don't flush any toilets.

Step 1: find the meter

In most Westminster-area neighborhoods the meter sits in a concrete box near the curb or the edge of the front yard. Some houses have it near the driveway. Lift the lid. You'll see a dial face with a large sweep hand and, on most meters, a small leak indicator: a triangle, star or tiny wheel.

Step 2: watch the leak indicator

Here's the test: with everything off, watch the small indicator for two full minutes. If it moves at all, even slowly, water is flowing.

Take a photo of the full reading too. If the indicator is hard to see, read the meter again in an hour and compare. Any change with all water off means a leak.

Step 3: rule out the easy ones

A moving indicator doesn't mean a slab leak yet. Check these first:

1. Toilets. Put a few drops of food coloring in each tank. Wait fifteen minutes without flushing. Color in the bowl means the flapper is leaking.
2. Irrigation. Walk the yard. A wet patch, a hissing valve box or a soggy strip of lawn points to the sprinkler system.
3. Outdoor hose bibs and pool fill lines. Look for drips and a running autofill.

If all of those are dry and the indicator still moves, the leak is in a pipe you can't see.

Step 4: yard line or house?

Many houses have a main shutoff valve where the water line enters the house, often near a front hose bib. Close it.

• Meter still moving with the house valve closed: the leak is between the meter and the house. That's the service line under the yard or driveway. See water line leak repair.
• Meter stops with the house valve closed: the leak is inside the house's plumbing. With no visible drips anywhere, the slab is the prime suspect. See slab leak detection.

If your house has no separate shutoff at the house, a plumber can make this split for you.

Step 5: hot or cold?

If the leak is inside the house, close the cold-water inlet valve on top of the water heater. If the meter stops, the leak is on the hot side, which is common with slab leaks. Reopen the valve afterward unless you're stopping a hot-line leak until a plumber arrives. Hot water slab leaks explains what to do with the heater in that case.

What to tell the plumber

Write down what you found: indicator moving or not, what happened with the house valve closed, and what happened with the heater inlet closed. That narrows the search before anyone arrives, and it's the first thing a good leak locator will ask.

Who to call for the meter itself

If the leak is at the meter or on the street side of it, that belongs to the water utility. In Westminster that's the City of Westminster Water Division. In Stanton it's Golden State Water. Everything on the house side of the meter is generally the owner's responsibility. The signs of a slab leak post covers the other clues to look for while you wait.