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The little brass valve that guards the water main
An irrigation backflow preventer stops sprinkler water from flowing back into the public supply. Seminole County requires yearly testing and a repair within 20 days of a failed test.
Somewhere near your water meter, or where the sprinkler line leaves the house, there's usually a small assembly of valves that most people never think about. It's a backflow preventer, and its job is to keep water that has been sitting in irrigation pipes, soaking in fertilized soil, from being pulled back into the drinking-water main. Seminole County requires these assemblies and wants each one tested every year.
What does a backflow preventer actually do?
It lets water flow one way only: from the utility's main into your property. If pressure in the main drops, water could otherwise be siphoned backward out of your sprinkler lines, and backpressure on your side can push it back too. The device closes or vents to stop either one.
The protection matters most where your water meets something you wouldn't drink. Sprinkler heads sit in soil, puddles and lawn chemicals, and in reclaimed-water neighborhoods a drinking-water line may run a few feet from a lavender one.
Which type do I have?
Seminole County's cross-connection program lists three device types it deals with: the pressure vacuum breaker, the reduced pressure assembly, and the reclaimed or dual check device. Florida's rule ranks the common devices by how much protection they give, weakest to strongest, in rule 62-555.360.
Backflow devices, from least to most protection (Florida rule 62-555.360)
| Device | Short name | Where you'd see it at home |
|---|---|---|
| Dual check | DuC | State minimum at a home with reclaimed water |
| Double check valve assembly | DC | Some service connections |
| Pressure vacuum breaker | PVB | Irrigation on a dedicated drinking-water meter, where backpressure can't develop |
| Reduced-pressure principle assembly | RP | Irrigation where backpressure could develop |
| Air gap | — | The strongest protection; a physical break in the line |
A PVB can't be used where backpressure could develop downstream, the state rule says; an RP is the choice there. If your sprinklers are tied into the house plumbing instead of a separate meter, the utility may rely on the backflow protection the Florida Building Code requires inside the home.
Why does my reclaimed-water home have one on the drinking meter?
Because reclaimed water and drinking water share your yard. When a home gets reclaimed service, Seminole County fits the potable meter with its own backflow device. County staff check those homes for cross-connections yearly, and the device gets an annual test, with worn parts swapped out. The state minimum at a residential connection with reclaimed water is a dual check. More on living with purple pipe is in our reclaimed water story.
How often does it need testing?
In Seminole County, every year. Under the county program, every service connection needs an assembly past the meter on the owner's side, and every assembly gets a yearly test. The county's responsibility ends at the meter itself; what comes after it belongs to the owner.
The state minimum is looser. Florida's rule calls for residential assemblies to be tested after installation or repair and at least every 2 years after that, and for dual checks to be refurbished or replaced at least every 5 to 10 years. Where the county rule is stricter, the county rule applies to its customers. If a city utility serves you, ask it what schedule it uses.
Florida rule 62-555.360 and Seminole County Utilities
Source: Seminole County Utilities, CCC Program (archived); Fla. Admin. Code r. 62-555.360
What happens if my device fails its test?
You have 20 days to fix it. Seminole County gives owners 20 days from receiving the failure notice to repair the assembly. After the repair, a certified backflow assembly tester must test it again and send the report to the county within 24 to 48 hours.
Don't ignore the notice or bypass the device. The program rests on county Ordinance 2014-23 (Chapter 270 of the county code), and a failed device leaves your yard's water with an open route back toward the public supply.
Who is allowed to work on it?
Testing is done by a certified backflow assembly tester. Repairs and replacements are plumbing work. In Seminole County, an irrigation system on drinking water needs a separate irrigation permit pulled by a licensed plumbing contractor, according to the county's Building Division. Irrigation contractors can pull that permit only when the system runs off reclaimed water from the county or Sanford.
Check any contractor's state license before you hire. Our hiring a plumber story explains the certified (CF) and registered (RF) license types and how to look one up.
What can a homeowner do?
Know where your device is and keep it reachable. Keep the yearly test reports with your house papers, and put the test date on the calendar if your utility doesn't send reminders. If a device is leaking, dripping or spraying, note what you see and call a licensed plumber; don't remove parts or plug a vent opening. If water is spraying hard, close the main shutoff and wait for help.
While you're at the controller, check the watering days and make sure the rain sensor still works. Hidden irrigation leaks turn up as a spinning meter dial, which our high water bill story explains how to check.
Readers often ask
Who sends the yearly backflow test notice in Seminole County?
Seminole County Utilities runs the Cross-Connection Control Program and requires the annual tests. If you're on a city utility, ask that utility how it handles notices.
Can I test my own backflow preventer?
No. After a repair, the county requires the test to be done by a certified backflow assembly tester, who sends the report to the county.
My sprinklers are on reclaimed water. Do I still need a backflow device?
Yes. For reclaimed homes, the county adds a device at the potable meter and requires a yearly test of it.
What's the difference between a PVB and an RP?
Both protect the supply, but an RP gives more protection. State rule bars a PVB wherever backpressure could develop downstream, and calls for an RP there.
How long do I have to fix a failed backflow device?
Seminole County allows 20 days from the date you receive the failure notice, followed by a retest by a certified tester.
Where this came from
- Seminole County Utilities — Cross-Connection Control Program (archived) — device types, yearly testing, 20-day repair, ordinance
- Fla. Admin. Code r. 62-555.360 — protection order, PVB limits, state test minimums, dual check service
- Seminole County Utilities — Reclaimed Water (archived) — backflow device on reclaimed customers' drinking meter
- Seminole County Building Division (archived) — who pulls irrigation permits
- Florida DBPR — Construction Industry Licensing Board (archived) — CF and RF plumbing licenses
- Florida DEP — Cross-Connection Control — reclaimed and drinking water look alike