Commercial Backflow Testing in San Jose

Commercial Backflow Testing in San Jose: The Short Answer

Every testable backflow assembly on a San Jose commercial, multi-unit or school property must be tested at least once a year by a certified tester, and again whenever it is installed, repaired or moved. The requirement comes from the State Water Board’s Cross-Connection Control Policy Handbook, and it is enforced by your water retailer: San Jose Water, San José Municipal Water (Muni Water) or Great Oaks Water. A failed assembly has 30 days to be repaired or replaced and pass a retest.

Which Water Retailer Requires Your Test?

The City of San José says there are three water retailers in the city, each with its own service area. Muni Water serves North San José, Alviso, Evergreen, Edenvale and Coyote Valley. Great Oaks Water describes its area as Blossom Valley, Santa Teresa, Edenvale, Coyote Valley and Almaden Valley. San Jose Water serves much of the rest of the city, plus neighboring West Valley cities. Edenvale and Coyote Valley appear in two lists, so check the name on the water bill or use the City’s utility services lookup.

Backflow testing rules by San José water retailer (checked October 2026)

San Jose Water

San Jose Water requires backflow prevention on fire services and some domestic services. It generally requires a reduced pressure (RP) assembly; a double check needs special circumstances and prior approval, and systems with pumps need an air gap. Assemblies must be lead-free and on the USC Foundation’s approved list, and San Jose Water asks owners to call its Backflow Department before buying one, because not every listed model meets its requirements.

San Jose Water has offered complimentary testing, but from January 1, 2027, it will no longer do routine testing of customer-owned assemblies, citing changes in state regulations. The annual requirement doesn’t change: owners will hire a certified tester, pay for the test and submit the report by the deadline San Jose Water sends. San Jose Water still runs the program, deciding which properties need protection, reviewing reports and following up on missed tests and repairs. For a portfolio with many assemblies, it is worth listing them now, with serial numbers and locations, before the first owner-arranged round.

San José Municipal Water

Muni Water’s written requirements (updated January 2026) put the customer in charge of installing, testing, maintaining, repairing and replacing assemblies, at its own expense. The main points for property managers:

• Notice: Muni Water sends a notice two months before the due date. A test done before the notice may have to be repeated unless Muni Water approved it.
• Testers: only testers certified by the American Water Works Association as backflow prevention assembly general testers, in good standing and registered with Muni Water. Email backflow@sanjoseca.gov for the current list before booking a test.
• Reports: original test reports on Muni Water’s current form, mailed by the tester or testing company. Email reports are accepted only from companies with an email agreement, and photos of reports are not accepted.
• Records: the customer keeps testing, maintenance and repair records for three years.
• Installation: no tees, branches or hose bibs before or on the assembly, and only Muni Water staff may shut the water off at the meter (call 408-277-3671). Replacing a fire service assembly needs San José Fire Department approval.

Great Oaks Water

Great Oaks Water has contracted with BSI Online to administer its backflow program. Its backflow page links to a BSI Online tool for finding a registered testing company and checking an assembly’s test status; questions go to backflow@greatoakswater.com.

What California’s Cross-Connection Rules Require

The State Water Board adopted the Cross-Connection Control Policy Handbook on December 19, 2023. It took effect on July 1, 2024, applies to every public water system in California and was last amended on April 21, 2026. The Board says it updates the cross-connection regulations that used to sit in Title 17 of the California Code of Regulations, adopted in 1987, and that those regulations are no longer operative. The handbook still relies on Title 22 for related rules, such as the definition of a distribution system and the requirements for recycled water use areas.

For property owners, the handbook’s key requirements are:

• Testable assemblies are field tested at least annually, and after installation, repair, depressurization for winter or relocation, by a certified tester.
• A new assembly must pass its test before the water system provides continuous service.
• An assembly that fails must be repaired or replaced within 30 days of notice of the failure, unless the water system’s plan allows an extension.
• Air gaps are inspected at least once a year.
• If a tester sees a backflow incident or an unprotected cross-connection, the water system must be told within 24 hours.

Types of Backflow Assemblies on Commercial Properties

The water retailer’s hazard assessment decides which assembly a site needs. The handbook defines these types and how they are installed:

The handbook’s list of high-hazard premises, which need an air gap or an RP, includes medical facilities, kidney dialysis centers, dental offices with water-connected equipment, veterinary clinics, laboratories and biotech facilities, electronics manufacturing, dry cleaners and commercial laundries, car washes, hotels and motels, gas stations, mortuaries, sites with an auxiliary water supply, premises with more than one connection to the water system, and business parks with a single meter serving several businesses. Restaurants and food service are not on that list; whether a kitchen needs an assembly at the meter depends on the retailer’s own assessment.

Installation rules matter for future tests. RPs, and DCs installed since the handbook was adopted, sit 12 to 36 inches above grade, with at least 12 inches of side clearance; a DC goes below ground only when the water system approves it. PVBs sit at least 12 inches above all downstream piping and outlets. For new assemblies and replacements, see backflow preventer installation.

Fire Sprinkler Services

Fire services are where many San Jose properties will see changes. The handbook requires every water system to protect fire sprinkler services with at least a double check within ten years of July 1, 2024, and a reduced pressure assembly for high-hazard fire systems, such as those using antifreeze, foam, wetting agents or corrosion inhibitors, or connected to an auxiliary water supply. A water system can propose a later date or another method for existing systems in its cross-connection control plan, so the retailer’s notice is what sets the timing for a given property.

Tester Certification in 2026 and 2027

The handbook requires every test to be done by a tester with a valid certification from a certifying organization the State Water Board recognizes. From July 1, 2026 to June 30, 2027, testers must be certified by an organization recognized in California; from July 1, 2027, only certifying organizations accredited to the ISO/IEC 17024 standard for certifying people count. A water system can also refuse a tester it doubts, and on top of state certification, Muni Water and Great Oaks keep their own registered lists. Before any test, confirm that the tester is accepted by your water retailer.

Keeping Many Assemblies on Schedule

Property managers and HOAs often have several assemblies per site, each with its own due date. A few habits keep them on time:

• Keep an inventory of every assembly: address, location, type, size, make, model and serial number, and the retailer’s account.
• Book tests when the notice arrives, so there is time to repair and retest inside 30 days if one fails.
• Keep three years of reports and repair records, as Muni Water requires its customers to do.
• Protect brass assemblies with a locking cage or cover; Muni Water recommends, but doesn’t require, cages or covers.

We test, repair and replace commercial assemblies across San Jose and the South Bay as part of our commercial plumbing service, for property managers, HOAs, businesses and schools.

Outside San Jose, each water supplier runs its own testing program. See our commercial plumbing pages for Santa Clara, Milpitas and Campbell, or the full service area.

Sources

Checked October 2026. City of San José: Water service in San José (three retailers) · Utility services lookup · Muni Water service areas (The Source of Your Water) · Backflow prevention and cross-connection control · Requirements for testing and maintenance of backflow prevention assemblies (rev. January 2026). San Jose Water: Backflow · Backflow testing changes, January 2027. Great Oaks Water: Home and service area · Backflow testing. State Water Resources Control Board: Cross-Connection Control Policy Handbook page · Cross-Connection Control Policy Handbook, amended April 21, 2026 (PDF) · CCCPH FAQ (PDF) · Backflow tester and cross-connection control specialist certification.