Backflow preventer testing in Prince George’s County, Maryland.
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Prince George’s County has the oldest sprinklered housing stock in Maryland, and that history decides who gets a backflow letter. The county mandated residential sprinklers in 1992, fifteen years before the rest of the state, so a Bowie or Upper Marlboro townhome from the 1990s may carry a system installed under a code that predates the testable-assembly era entirely. WSSC Water, the utility for nearly every public-water home in the county, states the current rule on its page titled Cross-Connection Control and Backflow Prevention Information for Residential Customers: the WSSC Plumbing and Fuel Gas Code requires annual testing for all installed testable backflow prevention assemblies, and a test immediately after installation, repair or relocation.
WSSC draws the line at the device, not the house. Homes built from 2007 to 2009 were required to install the testable version of a dual check valve on the fire sprinkler feed, and those assemblies are tested every year. Earlier and later standalone systems commonly have a non-testable dual check, which is not tested but is expected to be rebuilt or replaced every five years, work a single-family or townhome owner may do on a non-testable device without a permit. Lawn irrigation in Laurel, Clinton and the newer Brandywine subdivisions brings its own testable device, a pressure vacuum breaker or reduced pressure assembly, with the annual field test reported at spring start-up. A multipurpose 13D system that runs the heads off the house plumbing usually has no separate assembly to test.
The notice is new. In February and March 2026 WSSC mailed a Backflow Prevention Assembly Courtesy Notice to every customer whose records show a testable assembly, saying it would begin sending test-due advisements as a reminder. The letter names no deadline date, because the rule has none; the test is due a year after the last one. It does say plainly that WSSC does not perform field testing and that the assembly is part of the customer’s private plumbing. Prince George’s customers with questions about their own record can call the county line WSSC lists, 301-206-8601, or the program at 301-206-4004.
What the certified tester actually does at a Prince George’s house
WSSC permits only its own licensed and registered journeymen and master plumbers who hold cross-connection certification to test and repair assemblies, and it names the firms on a List of Plumbing Firms Providing Cross Connection-Related Services. The visit itself is short. The technician isolates the assembly, hooks a calibrated gauge to the test cocks, checks each check valve for tightness and, on a reduced pressure assembly, reads the relief valve, then tags the body with the date and the result. The report goes to WSSC electronically from a registered principal master plumber; that filing, not the tag, is what the courtesy notice calls proof of code compliance. If a company tests the device and leaves you a paper form to mail, the test has not been filed.
A failed test has two honest endings. A rebuild kit, new springs, seats and rubber in the existing body, fixes the common fault of a check that will not seat, and it is what we quote first when the body is sound. Replacement is the call when the body is cracked or corroded, when the model is old enough that parts are gone, which is a live issue on 1990s Prince George’s systems, or when a rebuilt device fails again within a year. Published Maryland plumber pricing frames the cost: Baltimore Plumber Service lists routine repairs at $250 to $600, a new or upgraded device at $600 to $1,200 and a full replacement at $1,500 to $3,000, while TLC Incorporated in Gambrills publishes $100 to $500 for repairs. Our own test is flat and under $150, and nothing beyond it happens without a written quote.
Leaving the annual cycle in Prince George’s County
WSSC gives sprinkler owners a documented exit. The testable assembly can be replaced with a non-testable dual check valve, after which the device is rebuilt or replaced every five years instead of tested every year. The condition is that a certified fire sprinkler contractor confirms the system still meets its hydraulic and flow design with the new device, and proof of that coordination goes to the WSSC Water Cross-Connection Control Program; the county Office of the Fire Marshal may add its own permit and inspection steps. On a thirty-year-old Fort Washington system that confirmation is a real calculation, not a signature, and it is the part of the job we do as sprinkler contractors. The rest of the county’s sprinkler work, including the recall-era heads common in the 1990s stock, is on the Prince George’s County page.
Pricing for every configuration is published on our cost guide, well-fed systems are covered on the well-water page, and the county overview lives on the Prince George's County page.
Questions Prince George's owners actually ask
My townhome was built in 1996 under the county mandate. Is it in the WSSC test cycle?
Only if the fire sprinkler feed has a testable assembly, one with test cocks on the body. Many 1990s systems have a non-testable dual check or none at all. We identify the device on the first visit; if it is testable it gets the annual test, if it is a dual check it goes on the five-year rebuild schedule WSSC describes.
Who sends the backflow notice in Prince George’s County?
WSSC Water, through its Cross-Connection Control Program. The county government and the fire marshal do not mail test notices. The 2026 letter is a courtesy advisement, not a fine, and the firm that tests the assembly files the result electronically so no further letter follows.
What if the test fails and the part is discontinued?
Then the device is replaced, and the new assembly gets its own installation test and WSSC filing. Discontinued parts are the usual reason a 1990s Prince George’s assembly is replaced rather than rebuilt. The quote comes before the work, in writing, with the published plumber ranges on this page as your reference point.
Can you test the irrigation backflow on the same visit as the sprinkler one?
Yes. Both are testable assemblies under the same WSSC rule, both are filed the same way, and one visit covers both. Irrigation results are reported at spring start-up, so if the sprinkler assembly is due in a different month we can align the two on the irrigation date.
Read before you book
- Backflow preventer testing and replacement in Baltimore: the metro water letter, the fire sprinkler assembly, and what happens when the test fails6 min read
- Backflow preventer replacement: when testing is not enough5 min read
- Hiring a fire sprinkler contractor in Prince George’s County: the oldest 13D stock in the country, DPIE, the fire marshal inspection and the stamp the county wants8 min read
- Fire sprinkler system installation in Prince George’s County: the DPIE permit, the WSSC meter, and how a Bowie infill, a Laurel townhome row and a Brandywine well lot each run7 min read