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Backflow testing companies in Maryland

From DC Water's list of companies approved to test backflow assemblies in its water system, read September 29, 2026. Maryland publishes no statewide tester list we can use, so we start with its largest utility lists.

99 companies on the utility list
42 listed here, phones checked on Google

The lists we use in Maryland

Being on a utility's list means that utility lets the company file backflow test reports in its system. It is not a state license. See Maryland backflow rules and how testers are certified.

Backflow testing businesses in Maryland

Ranked by our quality score: on the utility's current list, a phone that matches the business's Google profile, and a website. Nobody can pay to move up.

Sky Plumbing

90/100
✓ MD Utility-Approved Tester Verified ★ 4.9 (177 reviews) On DC Water list Backflow Testing

12342 Wilkins Ave, Rockville, MD 20852

Call (240) 207-1212 Details Website

Verified Oct 2026 · Unclaimed listing

Towns with approved testing companies

All 42 backflow testing businesses in Maryland, by town

Adelphi: J&J Plumbing and Heating

Annapolis: First Class Plumbing LLC

Beltsville: Madden Plumbing & HVAC Inc, WE Bowers, Youngblood HVAC

Bethesda: Unlimited Home Services LLC

Bladensburg: Al Gleeson Electrical Co. Inc.

Capitol Heights: Free Line Plumbing

Charlotte Hall: Fortech Plumbing Company

Cockeysville: Flo-Tron Contracting, Inc

Derwood: JF Plumbing & Heating

Frederick: K.G. Johnson, Inc

Gaithersburg: Delmar Plumbing, LLC, Harvey W. Hottel, James A Wheat & Sons, Mallick Plumbing & Heating, Inc, Master Plumbing & Mechanical

Germantown: O'Conor Plumbing Services, LLC

Glenn Dale: American Combustion Industries Inc

Halethorpe: Nationwide Plumbing & Heating LLC

Hanover: Summit Fire & Security

Hyattsville: All Season Plumbing, Heating, and A/C, Inc., JP Spadaro and Sons Inc (Spadaro Plumbing)

Kensington: Acker & Sons, Inc

Lanham: CRW Mechanical

Largo: Definitive Mechanical LLC

Mechanicsville: All Mechanical and Plumbing LLC, Puyenpa Mechanical Construction

Monrovia: Shary's Plumbing

Nottingham: Patriot Backflow & Gas Inc

Rockville: A Tasker Inc, T/A Salco Mechanical Contractors, Shapiro & Duncan, Inc., Sky Plumbing

Silver Spring: James R Ballard Plumbing & Heating Inc, Thomas E Clark Inc

Sykesville: Charles A Klein & Sons, Inc

Takoma Park: Durance Plumbing

Upper Marlboro: H&D Mechanical LLC, The Severn Group, Welch & Rushe Inc

Walkersville: Premier Fire Protection Services, LLC

White Plains: ADJ Sheetmetal Inc

Questions

Where do these Maryland backflow testing companies come from?

Maryland publishes no statewide list of backflow testers that we can use, so every business here is on the approved list of DC Water: companies allowed to file backflow test reports in that water system. We read the list on September 29, 2026 and checked each company's phone against its Google profile.

Who is allowed to test a backflow preventer in Maryland?

A tester certified as Maryland's rules require, and usually one your water utility accepts. Our Maryland rules guide links the state rule. Ask any company for the tester's certificate number before the test.

How often does a backflow assembly need testing?

Most water utilities require testable backflow assemblies to be tested at installation and then every year. Your utility's notice gives your deadline and how the report is filed.

Never miss your annual backflow test

Most water utilities require the backflow assembly on an irrigation, fire or commercial line to be tested every year, and a missed test can mean a shutoff notice. Tell us when yours was last tested and we'll text you a month before it is due, with certified local testers ready to book.

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