Backflow testing: why the utility sent me a letter and what happens next

The letter is from the utility, it mentions a cross-connection control program, it names a device on your property you may never have noticed, and it wants a test report by a date. It is not a scam and it is not a bill, yet. It is the utility’s way of protecting the water everyone drinks, and it puts one small annual task on your list.

What a backflow preventer does

Water is supposed to flow one way: from the utility’s main, through your meter, into your house and yard. If pressure in the main drops, because a hydrant is opened, a main breaks, or a pump goes down in a storm, water can be pulled backward from your property into the main, and anything in it goes along.

The obvious example here is irrigation. A sprinkler head sitting in a puddle of fertilizer and weed killer is a direct path from the lawn into the public supply if the pressure reverses. A backflow preventer is a valve assembly that only lets water go forward. Under normal pressure you never know it is there; on the day the main loses pressure, it is the only thing between the lawn and the neighborhood’s kitchen taps.

Who has one, and where it is

Utilities across Lee and Collier County require a device wherever there is a plausible path for contamination:

• Homes with irrigation on potable water. The most common case. The device is usually a brass assembly on two risers a foot or so above the ground near the meter, sometimes in a green box at grade.
• Homes with a private well and a city water connection. Common in Lehigh Acres, Alva, Buckingham, eastern Estero, and Golden Gate Estates, where the well feeds irrigation and the utility feeds the house. Any chance of the two touching requires a device.
• Reclaimed water customers. Cape Coral, Fort Myers, Bonita Springs, and Collier County all deliver reclaimed water for irrigation. A property with both reclaimed and potable service needs protection between them.
• Condos, multi-family, and commercial. Almost always, usually a larger device the association or owner is responsible for.
• Pools with an auto-fill and homes with a fire sprinkler system, in some jurisdictions.

If you are not sure whether you have one, walk from the meter toward the house. A pair of shutoff handles on a brass body with small capped test ports is the device.

Why the utility sends the letter

Backflow preventers are mechanical. They have springs and rubber check discs, they sit in sun, salt air, and irrigation water, and they wear. A failed device looks exactly like a working one, so the only way to know is to test it. Florida requires utilities to run a cross-connection control program, and Lee County Utilities, the City of Cape Coral, Bonita Springs Utilities, the City of Fort Myers, Collier County Public Utilities, and the City of Naples each require devices on their systems to be tested by a certified tester on a schedule, once a year for most residential assemblies. The letter arrives when yours is due.

The utility does not do the test. You hire a certified tester, who files the result with the utility. Many letters include a list of approved testers; a licensed plumber with backflow certification is on it.

What a certified tester does, and what usually fails

The test happens at the device, outside, and you usually do not need to be home as long as the tester can reach it and shut the irrigation off for the duration. The tester:

1. Closes the downstream shutoff so nothing on the property is drawing water through the device.
2. Connects a calibrated test gauge to the test ports.
3. Checks that each check valve holds against reverse pressure, and on a reduced pressure assembly, that the relief valve opens at the correct point.
4. Records the readings, the device details, and the pass or fail result on the utility’s form.
5. Restores service and files the report.

The gauge is calibrated on a schedule and the tester’s certification number goes on the report; those two things make it acceptable to the utility.

What usually fails:

• A fouled check valve. Sand, a PVC shaving, or hard water scale holds a check disc off its seat.
• Worn rubber. Check discs and the relief valve diaphragm harden in the heat and stop sealing; in our sun it comes sooner.
• A relief valve that spits. A reduced pressure assembly discharging from the port under the body is doing its job, but an internal part has failed and it is dumping water on the ground.
• Seized shutoffs. The ball valves on each end corrode and will not close, so the device cannot even be tested until they are replaced. A failed test is not a crisis: the device is rebuilt with a repair kit or replaced, retested, and filed.

What happens if you ignore the letter

Utilities follow a sequence. A first letter is a reminder, a second gives a final date, and after that most utilities in Lee and Collier County add a monthly charge to the water bill for a property out of compliance. The last step is a shutoff of the irrigation service or the whole account until a passing test is on file. Seasonal residents get caught by this more than anyone: the letter arrives in June, nobody is home, and the October bill has a surprise on it. If you are away for the summer, schedule the test before you go, or have your caretaker watch the mail.

Repair and replacement are licensed work

Testing needs a certified tester. Rebuilding or replacing an assembly is plumbing work that in Florida must be done by a licensed plumbing contractor, and a replacement is permitted work with its own inspection. The device has to be the right type for the hazard, installed at the correct height and orientation with clearance for testing, and the plumber who fixes it can file the passing report. Cutting the device out, or replacing it with a type the utility does not accept, moves the problem from the lawn to the water everyone on the street drinks.

If you have a letter in hand, tell us the utility, the date on it, and where the device is on the property. If a device is spraying water or you failed a test and need a repair, send a photo. We test, repair, replace, and file the report.