Backflow Testing & Certification

State-Certified Annual Backflow Testing for Wisconsin Businesses

Backflow prevention assemblies protect your municipal water supply from contamination. They’re required by Wisconsin code on most commercial properties, irrigation systems, fire suppression systems, and any cross-connection where contaminated water could potentially flow backward into the public water supply. Annual testing is mandatory, and the test must be performed by a state-certified backflow tester.

Doro Plumbing performs backflow testing across southeast Wisconsin for property managers, building owners, restaurant operators, irrigation system owners, and anyone else with a backflow assembly that needs annual certification. We submit reports directly to your municipality so the compliance side is handled.

What We Test

Reduced Pressure Zone (RPZ) assemblies – the highest-protection device, used in most commercial and high-hazard applications. Required testing every 12 months in Wisconsin.

Double Check Valve (DCV) assemblies – lower-hazard applications, also requires annual testing.

Pressure Vacuum Breakers (PVB) – common on irrigation systems, annual testing.

Atmospheric Vacuum Breakers (AVB) – generally not testable, but we’ll inspect and confirm proper operation.

We test all major brands: Watts, Febco, Wilkins, Ames, Apollo, and others.

What’s Included in Our Test

• Visual inspection of the assembly for proper installation, orientation, and condition
• Differential pressure test following ASSE/AWWA test procedures
• Detailed test report with all required pressure readings and pass/fail determination
• Direct submission to your municipality (We Energies and most southeast Wisconsin water utilities)
• Repair quote if the assembly fails (provided same day in most cases)
• Tagged and dated so you have a visible record at the assembly
• Reminder system so we contact you ahead of next year’s deadline

When Backflow Testing is Required

In Wisconsin, annual backflow testing is required for:

• All RPZ and DCV assemblies – regardless of property type
• Irrigation systems with backflow protection (most commercial, many residential)
• Fire sprinkler systems with double-check or RPZ protection
• Restaurants with soda lines, dish machines, or boiler systems
• Medical and dental offices with high-hazard fixtures
• Auto shops, car washes, and industrial properties with cross-connections
• Multi-family properties with boiler systems or shared mechanical rooms

Most municipalities send notification 30-60 days before your annual deadline. Miss the deadline and you may receive fines, water shutoff notices, or be required to add additional protection.

What If My Assembly Fails?

Failed assemblies need repair or replacement before re-testing. Common failures we see:

• Worn check valves – usually rebuildable with manufacturer kits
• Failed relief valves on RPZs – usually rebuildable
• Cracked bodies – require full replacement
• Improper orientation from previous installation – sometimes can be re-set, sometimes requires re-installation

We can typically rebuild a failed assembly the same day if we have the right kit on the truck. Full replacement (which may be required if the body is damaged or the assembly is obsolete) takes 1-3 days depending on parts availability.

Why Use a Local Plumber Instead of a Backflow-Only Service

A few backflow-only services exist in Wisconsin. They’re fine for the test itself, but if the assembly fails, you’ll need a separate plumber to repair it. Using us for both means the testing tech can rebuild on the spot in most cases, saving you a second visit and a second bill.

We’re also licensed plumbers, so if your assembly is undersized, improperly installed, or in the wrong location, we can correct that as part of the same project rather than telling you to call someone else.

Doro Plumbing · (262) 229-5632 · Hartford, WI