Dozens of water meters set stacked on a rack of shelves in the shop at Chaparral City Water Company.

They are still encrusted with the dirt and rust from years in the ground.

All of these meters have been pulled out and tested for accuracy.

CCWC is demonstrating its meter testing equipment for The Times. There is an array of pipes and tanks with gauges that might bring to mind a Rube Goldberg plumbing apparatus.

CCWC’s Don Long has installed three meters in a line along the testing bench. He says two of the meters being tested have come in because the customers say they are over reading the water usage. The third meter is a new one being used to fill out the line.

The meters being tested have been in use a long time. One has read 1.34 million gallons in its lifetime, and the second more than 3 million gallons.

Long will run 10 gallons of water through the meters at three different rates, one running at half a gallon per minute, the second test is at three gallons per minute and the third is 100 gallons at a rate of 25 gallons per minute.

Jeffery Stuck with EPCOR said each represents different types of usage around the house -- the slowest rate for flushing a toilet or running a faucet. The second rate reflects usage for a washing machine or dishwasher. The third flow is what might be used for irrigation or running a garden hose.

Stuck explains that the standard tolerances for accuracy of the meters is set by the Arizona Corporation Commission and the American Water Works Association. That tolerance is plus or minus 3 percent.

The Arizona Department of Weights and Measures checks the testing equipment on a periodic basis to insure its accuracy.

The first phase of the test takes 20 minutes to run the 10 gallons at half gallon per minute.

At the conclusion Long announces that both the meters have indeed failed the test, but not for the reason the customer thought.

Both meters were actually under reading the flow of water, not over reading.

Long said it is not unusual for an older meter to under read.

“I’ve been at this for 20 years and I think I have tested two meters that were over reading the flow,” Long said. “That was because they were set wrong when they were installed.”

The meter was not set for the proper sized pipe.

For the second and third phase of the testing, both meters were within the tolerance allowed and passed.

These meters will not go back in the ground, even if they had passed on all three tests. The failure does mean the customer will not be charged the $35 testing fee.

Stuck said Long usually draws the assignment for customer complaints on meters. He first checks the meter to see whether there is water flowing through it. All meters have a small triangle or wheel that will turn whenever there is water flow.

If the meter shows water is flowing the next step is to shut off the water at the house. If that stops the flow there is a problem with water flow beyond the shut-off inside the house.

If the water continues to flow after it is shut off to the house, the area of flow or leaking has been narrowed to between the meter and the house.

Searching for leaks around the house is another story, and one we asked a plumber to help with.