Why start with the water meter?
The meter is the one place where every gallon your home uses is counted, including water you cannot see, such as a slow drip under the slab or a cracked irrigation line under gravel. The City of Mesa's first step for a suspected leak is to compare your current usage with previous months, because a sudden increase can point to a leak, an irrigation problem or a change in how the household uses water. The City of Phoenix gives the same advice: unexplained month-to-month or year-to-year increases in cost or water units may indicate a leak.
Small leaks add up. EPA WaterSense estimates that the average household's leaks can waste more than 9,300 gallons a year, and that about nine percent of homes have leaks wasting 50 gallons or more per day. Fixing easily corrected leaks can save homeowners about 10 percent on their water bills, according to WaterSense.
How do you find and read the meter?
The City of Chandler says the meter is generally near the sidewalk in front of the home, in a direct line with the main outside faucet. It sits in a box in the ground with a lid. Lift the lid carefully and set it back in place when you are done.
Most Valley cities now use digital meters. The Smart Home Water Guide, published for Arizona homeowners, notes that digital meters need light to wake up, so you may need to shine a flashlight on the display. Mesa's instructions say to close and reopen the register lid for about two seconds to activate its meters. The display alternates between the meter reading and the current flow rate. Mesa notes that Sensus meters label the flow screen "FL" and show gallons per minute.
Older analog meters have a large sweep hand that measures gallons or cubic feet. Most also have a low-flow indicator, a small triangle, star or gear that turns whenever water passes through the meter, even a trickle too small to move the sweep hand.
What is the step-by-step meter test?
Pick a time when nobody needs water for a while, then work through these steps from the city and WaterSense guidance.
- Turn off all water use inside and outside: faucets, showers, toilets, the dishwasher, the washing machine, the water softener's regeneration cycle, the pool autofill and every irrigation zone.
- Digital meter: watch the flow-rate screen for at least 10 flashes. Chandler and the Smart Home Water Guide say that if the number is greater than zero on any flash, you have a continuous leak.
- Analog meter: watch the sweep hand and the low-flow indicator. Neither should move when no water is being used. If one moves, Chandler suggests waiting 10 minutes and checking again to confirm a slow leak.
- For very slow leaks, write down the full meter reading, wait 20 minutes without using water, and read it again. If the second number is higher, water went somewhere.
- EPA WaterSense offers a longer version: check the meter before and after a two-hour period when no water is used. If the reading changes at all, you probably have a leak.
How do you tell if the leak is inside the house or outside?
Once the meter shows a leak, narrow it down. Chandler's instructions are to turn off the water to the house at the home's own shutoff valve, which is usually under the outside faucet near the front of the house. Then look at the meter again.
If the meter stops moving with the house valve closed, the leak is somewhere inside the home's plumbing or fixtures. If the meter keeps moving with the house valve closed, the leak is between the meter and the shutoff valve, on the service line that runs through your yard. The Smart Home Water Guide calls this the isolation method: closing valves one section at a time until the meter stops.
Where do Phoenix Valley homes usually leak?
Mesa's checklist names the usual suspects: toilets, irrigation systems, water softeners, hose bibs and pool autofill systems. Desert landscaping adds a few of its own, because drip lines and valves are often buried under rock where a leak never shows on the surface.
- Toilets: put a few drops of food coloring in the tank. EPA WaterSense says that if color shows up in the bowl after 10 minutes, the toilet is leaking, and Chandler notes the rubber flapper usually needs replacing.
- Irrigation: Chandler points out that irrigation leaks may not be noticeable unless the system is running. Turn the controller on manually and walk the yard looking for broken heads. Phoenix suggests checking for soggy ground around sprinkler valves, valve boxes and backflow preventers, and inspecting drip lines for cracks and missing or broken emitters.
- Abandoned zones: Phoenix recommends capping or disconnecting sprinkler heads, drip lines and old zones that no longer water anything.
- Pools: Phoenix estimates that about one in 20 pools leak, and that a leak of an inch per day can waste up to 100,000 gallons in a year.
- Faucets and showerheads: WaterSense says a faucet dripping once per second can waste more than 3,000 gallons a year.
Who fixes the leak, you or the city?
In Phoenix, the city says issues from the street to the water meter are the city's responsibility, and issues after the meter are the homeowner's. Mesa draws the same line: contact the city if water is leaking at the meter box or surfacing in the street, and contact a plumber for leaks on your property beyond the meter, including fixtures and irrigation equipment. If you are in another Valley city, check with your city's water department before assuming who owns a leak near the meter.
If the meter test points to the service line or to a hidden leak inside the home, write down your readings and what you turned off. That record makes a leak detection visit faster to plan, and it helps if you later ask your city about a high bill.
Common questions
How long should I watch the meter before deciding there is no leak?
Chandler and the Smart Home Water Guide say to watch a digital flow screen for at least 10 flashes, and the Smart Home Water Guide suggests a 20-minute before-and-after reading for slow leaks. EPA WaterSense suggests a two-hour test when no water is used.
My meter shows flow but I cannot find any water. What next?
Close the house shutoff valve and look again. If the meter stops, the leak is inside the home, possibly a toilet or a hidden pipe. If it keeps moving, the leak is likely on the service line between the meter and the house.
Can a water softener or pool make the meter move when nothing is on?
Yes. Mesa lists water softeners and pool autofill systems as common leak sources, and both can also use water on their own schedule. Make sure neither is regenerating or filling before you run the meter test.
Is a leak at the meter box my responsibility?
In Phoenix and Mesa, leaks at the meter box or in the street are the city's to fix, and leaks after the meter belong to the property owner. Other cities set their own rules, so check with your water department.