Plumbing Directory: Purpose and Scope

The backflow prevention service sector spans licensed testers, certified installers, inspection authorities, equipment manufacturers, and repair contractors operating under a patchwork of state and municipal licensing frameworks across the United States. This directory maps that professional landscape, organizing entries by service category, geographic jurisdiction, and qualification type. The Backflow Listings it supports are structured to serve industry professionals, facility managers, water utility staff, and property owners navigating a regulated service market — not a general consumer marketplace.

How to interpret listings

Entries in this directory represent service providers and organizations operating within the backflow prevention and cross-connection control sector. Each listing reflects a professional category, not a certification endorsement or quality rating. The directory does not rank providers, recommend one over another, or validate the licensing status of any individual or company at the time of search.

Listings are organized along three primary axes:

1. Service type — tester, installer, repair technician, inspection authority, or equipment supplier
2. Geographic scope — state-level licensing jurisdiction, county, or municipal service area
3. Credential category — the licensing or certification body under whose authority the provider operates

Licensing for backflow prevention work is administered at the state level through bodies such as the Texas State Board of Plumbing Examiners, the California Department of Consumer Affairs Contractors State License Board, and equivalent agencies in each jurisdiction. In states without a unified backflow-specific license, oversight may fall under a general plumbing contractor license combined with a separate backflow tester certification issued by the local water authority or an approved third-party program.

Testing and certification competency standards are widely benchmarked against ASSE International's Series 5000 program — specifically ASSE 5010 for field testers and ASSE 5020 for inspectors — and against programs administered by the American Water Works Association (AWWA) and the USC Foundation for Cross-Connection Control and Hydraulic Research. Listings that indicate certification under these programs are doing so based on provider self-disclosure; verification of current certification status rests with the credentialing body.

The How to Use This Backflow Resource page describes the navigation structure in detail.

Purpose of this directory

Cross-connection control programs operated by water utilities across the United States require that backflow prevention assemblies be tested annually by licensed or certified personnel, with test reports submitted to the local water authority on a defined schedule. The regulatory obligation falls on the property owner or the entity responsible for the water service connection, not the utility itself. Locating a qualified tester who holds the appropriate jurisdiction-specific credential is a concrete compliance task — one this directory is designed to support.

Beyond annual testing, backflow prevention work encompasses initial assembly selection, installation to code, post-installation inspection, and repair or replacement when an assembly fails a field test. Each of these functions may be performed by different categories of licensed professionals depending on state law. A licensed plumber may be authorized to install an assembly but not to certify a test result; a certified tester may be authorized to test but not to make mechanical repairs. The directory reflects these categorical distinctions.

The U.S. Environmental Protection Agency's Cross-Connection Control Manual — a foundational regulatory reference for water systems operating under the Safe Drinking Water Act — identifies the protection of public water supplies from backflow contamination as a core public health infrastructure requirement. State primacy agencies, operating under EPA oversight, translate that federal framework into enforceable state rules. This directory operates within that regulatory structure by making the professionals who carry out compliance work identifiable and accessible.

What is included

The directory covers four primary provider categories relevant to the backflow prevention sector:

1. Certified backflow testers — individuals credentialed to perform field tests on backflow prevention assemblies and submit results to water authorities
2. Licensed installation contractors — plumbing contractors authorized under state licensing law to install backflow prevention assemblies at the appropriate hazard rating
3. Repair and maintenance technicians — professionals qualified to rebuild or replace components in assemblies manufactured by brands such as Watts, Febco, Wilkins (Zurn Industries), Apollo, and Ames Fire & Waterworks
4. Equipment suppliers and distributors — commercial sources for assemblies, test kits, and replacement parts meeting ASSE International and USC FCCCHR listing requirements

The directory does not include manufacturers directly, unlicensed handymen or general contractors without applicable plumbing credentials, or suppliers of non-listed assemblies that have not been evaluated under the USC Manual of Cross-Connection Control or an equivalent testing program.

Device categories represented in the directory span the four assembly types governed by ASSE standards: the Reduced Pressure Zone assembly (ASSE 1013), the Double Check Valve Assembly (ASSE 1015), the Pressure Vacuum Breaker (ASSE 1020), and the Atmospheric Vacuum Breaker (ASSE 1001). High-hazard applications — those involving chemical injection, irrigation with fertilizer systems, or industrial process water — require RPZ assemblies and typically mandate a narrower subset of licensed providers. Low-hazard applications may be served by a broader installer pool under DCVA requirements.

How entries are determined

Entries are sourced through a structured collection process drawing from state licensing board records, water authority approved-tester lists, ASSE International's published member and certified-professional directories, and AWWA-affiliated cross-connection control programs. Where a state licensing board maintains a publicly searchable database — such as the Texas State Board of Plumbing Examiners' online license verification portal — that database serves as the primary sourcing reference for provider qualification data.

The determination of which providers appear in the directory follows a defined threshold structure:

1. Credential verification — the provider must hold or have held a verifiable license or certification under a named credentialing authority
2. Jurisdictional relevance — the provider's service area or licensed jurisdiction must correspond to at least one US state or municipal service territory covered by the directory's geographic scope
3. Category alignment — the provider's documented services must fall within one of the four categories described in the prior section
4. Regulatory standing — providers with documented suspension, revocation, or lapse of required credentials are excluded until reinstatement is confirmed through the issuing authority

The Backflow Authority directory purpose and scope page should be read alongside the listing index for full context on how entries are classified. Entries are not guaranteed to reflect real-time license status; the issuing state board or water authority is the authoritative source for current standing.