- Commercial Plumbing
- Commercial
- Backflow
- 7-minute read
Water is supposed to move one direction: from the main into the building. A pressure drop in the street, or a pump or boiler pushing back, reverses it. The device that stops the reversal is small, mechanical, and required by the City of Racine to be tested annually.
A backflow preventer uses spring-loaded check valves — plus a relief valve or air gap on higher-hazard types — so water only flows from the public main into the building, never back. Racine's cross-connection program (Wisconsin NR 810.15 and SPS 382.41) requires every backflow preventer assembly to be tested once a year by a certified tester, at the owner's expense.
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Key takeaways
- Backflow happens two ways: backsiphonage when street pressure drops (a main break, a hydrant flow) and backpressure when something inside pushes harder than the supply.
- The backflow preventer type follows the hazard: a hose bib gets a vacuum breaker; a boiler, irrigation system or commercial process gets a testable assembly.
- Racine's program is administered through HydroCorp; commercial, industrial and public buildings get surveyed, and assemblies get tested annually.
- Residential cross-connection checks in Racine are coordinated with the utility's meter replacement, which happens about every 20 years.
What is backflow, and where does the reversal start?
A cross-connection is any point where the drinking water system touches a possible source of contamination. The Racine Water Utility's own example is the most common one: a garden hose, which can be sitting in a bucket of fertilizer or a pool when the pressure drops.
Backsiphonage
Pressure in the street falls below pressure in the building — a water main break, a fire hydrant opened nearby, a pump drawing hard. The building's water gets pulled back toward the main, carrying whatever it touched.
Backpressure
Something inside pushes harder than the supply: a boiler, a booster pump, a carbonation system, an elevated tank. Water is forced backward through the service line.
The utility lists dishwashers, toilets, pressure washers, boilers, pools and lawn sprinkler systems as everyday cross-connections. Each one needs a backflow preventer matched to its risk.
How does a backflow preventer stop the reversal?
Every backflow preventer uses the same idea — a check that only opens in one direction — and adds safeguards as the hazard rises.
| Device | How it works | Typical use | Testable? |
|---|---|---|---|
| Hose bib vacuum breaker | A small check and air inlet on the spigot; if pressure drops, air enters instead of hose water | Outdoor faucets — the utility supplies up to two per home in Racine | No |
| Atmospheric vacuum breaker (AVB) | An air inlet that opens when flow stops, breaking any siphon | Irrigation zones, some fixtures | No |
| Pressure vacuum breaker (PVB) | A spring-loaded check plus an air inlet, rated for continuous pressure | Lawn irrigation systems | Yes — annually |
| Double check valve assembly (DCVA) | Two independent spring-loaded checks in series | Fire sprinklers, low-hazard commercial | Yes — annually |
| Reduced pressure zone assembly (RPZ) | Two checks with a relief valve between them that dumps water to a drain if either check fails | Boilers, chemical feeds, high-hazard commercial and industrial | Yes — annually |
| Air gap | No device at all — a physical gap between the outlet and the receiving vessel | Softener recharge lines (Racine requires a one-inch air break), sinks, tanks | Visual inspection |
Which rules apply to a backflow preventer on my property?
The Racine Water Utility runs a cross-connection control program under Wisconsin Administrative Code NR 810.15 and the state plumbing code, SPS 382.41. The program has two tracks.
Commercial, industrial, public
Surveys of every facility on the retail water system, administered by HydroCorp, with required installation of devices where cross-connections are found. All assemblies must be tested once a year by a certified tester, at the owner's expense.
Residential
Cross-connection inspections coordinated with the utility's meter replacement, roughly every 20 years. Typical corrections: vacuum breakers on hose connections, a one-inch air gap on the softener drain, protection on irrigation and on boiler heating systems.
Villages and other utilities
Mt Pleasant, Sturtevant and Caledonia customers on other water systems fall under their own utility's program; the state code requirement is the same. Which side of the village line you are on is explained under plumbing in Caledonia.
PM's backflow prevention installation and testing service installs the assembly the survey calls for and completes the annual test report for Racine-area commercial accounts.
How is the annual backflow preventer test done?
Locate and isolate the assembly
The tester closes the downstream shutoff, which interrupts water to the protected zone for the length of the test — usually under half an hour.
Connect a calibrated test kit
A differential gauge is attached to the assembly's test cocks.
Test each check and the relief valve
Each check must hold against a set pressure difference; on an RPZ the relief valve must open at the correct point. Numbers are recorded, not just pass or fail.
Repair and retest if needed
A failed backflow preventer check usually means a worn spring or a seat fouled by debris. Rebuild kits are standard for most assemblies.
File the report
The tester submits the results to the program administrator. Keep a copy; the next survey asks for it.
Debris on a check seat after a main break, a relief valve that weeps because a check is fouled, freeze damage on an outdoor RPZ that was not drained in the fall, and springs simply worn out after years of service.
Why not wait for the utility to notice?
- It is required, not optional. The program is state code applied locally, and the utility can require corrections and testing as a condition of service.
- An untested RPZ can flood a mechanical room. The relief valve is designed to dump water when a check fails; with no drain or a blocked one, it floods.
- Boiler water in a drinking line is a real contamination. Treatment chemicals in a heating loop are exactly what an RPZ on the make-up line exists to keep out.
- A pass is cheap; a failure is not. A tester who also carries rebuild kits turns a failed test into a same-visit repair instead of a return trip.
Due for an annual backflow test in Racine or Kenosha, or got a survey letter asking for a device? PM installs, tests and files the report.
Call (262) 770-0039Request serviceBackflow preventer questions
Do I need a backflow preventer on my home?
Every home has some: vacuum breakers on hose bibs and an air gap on the softener drain are the residential basics the Racine program checks. A lawn irrigation system or a boiler adds a testable assembly.
Who can test a backflow preventer in Wisconsin?
A certified cross-connection control tester. The Racine program requires the annual backflow preventer test be done by a certified tester and the results submitted; the property owner pays for the test.
Can a backflow preventer be installed indoors?
Yes, and in Wisconsin it usually should be — an outdoor RPZ freezes. Indoor installs need a floor drain sized for the relief valve discharge and clearance to reach the test cocks.
Is water supposed to come out of a backflow preventer?
On an RPZ, a brief discharge from the relief port during pressure swings is normal; a steady drip or stream means a check is fouled or failed and the assembly needs service. Other types should never discharge water at all.
Interceptors, boilers and the rest of the commercial menu
Boilers and grease interceptors are the two systems that most often bring a backflow preventer requirement with them; both are covered below. PM's commercial boiler service handles the make-up feed and its RPZ together.
Backflow preventer installation, annual testing and reporting for Racine County businesses. Licensed, insured, and on the schedule before the notice arrives. That is the practical difference when you look for a local plumber near Racine and Mt Pleasant: the person who quotes it is the person who does it.
Call (262) 770-0039Request service- City of Racine Water Utility, Cross Connection Control (NR 810.15, SPS 382.41, HydroCorp administration, annual testing, residential program): cityofracinewi.gov/water/water-quality/crossconnection