Commercial plumbing in Washington, DC covers restroom and fixture repairs, water heaters, drain and main line backups, gas appliance hookups and the annual backflow tests DC Water requires. Permitted work goes through the DC Department of Buildings, and only a contractor holding a DC license for that trade can apply. Call the number on this page to be connected with a local plumber in Washington, DC who handles commercial and multifamily jobs.

Typical commercial calls
- Clogged restroom lines, urinals and floor drains.
- Kitchen drain backups and grease buildup in lines.
- Commercial water heater repair and replacement.
- Gas lines for ranges, fryers and heaters.
- Main sewer backups that shut down a whole building.
- Leaks in ceilings of mixed-use and apartment buildings.
- Backflow assembly testing, repair and replacement.
Backflow is an annual obligation
Most commercial buildings have at least one backflow assembly at the water service connection. DC Water's cross-connection control office requires these to be tested every year, with reports sent to that office. Fire sprinkler lines, boilers, irrigation and food service equipment are common reasons a building needs one. Keep the test schedule on the same calendar as other building maintenance so a deadline is not missed.
Permits through the Department of Buildings
The DC Department of Buildings issues Plumbing and Gas Permits for work such as new fixtures and new or replacement gas appliances, and Mechanical Permits for new or replacement HVAC equipment. Only a contractor holding a DC license for that trade can apply for a trade permit, and the plumbing application, which covers water heaters and backflow preventers, is signed by a DC Master Plumber or Gas Fitter. Tenant build-outs and kitchen renovations nearly always involve permits, so start that conversation early.
Sewer backups and storms
DC Water runs the public sewer system. About one-third of the District is on a combined system, where storm runoff and sewage share pipes, and heavy summer storms can overload drains and push water back into below-grade spaces. Restaurants and retail in basement-level units feel this first. A plumber can clear a blocked building drain, run a camera to find the cause and talk through backwater valves. If the problem is in the public sewer, call DC Water's 24-Hour Command Center at 202-612-3400.
Gas safety on site
If anyone smells gas, get people out first, then call 911 and Washington Gas at 844-WASHGAS (844-927-4427), option 1, from a safe place. A plumber can repair piping once the utility has made the site safe.
What drives commercial pricing
Cost depends on the scope, after-hours or weekend timing, access in occupied buildings, permit requirements, equipment size and whether work must be staged to keep the business open.
Commercial Plumbing questions from Washington homeowners
Do businesses in DC need annual backflow testing?
Who can pull a commercial plumbing permit in DC?
Who do I call if the sewer backs up into my business?
What should staff do if they smell gas?
Related plumbing services in Washington
Commercial Plumbing in nearby cities and towns
Arlington County
Alexandria City County
Fairfax County
Fairfax City County
Falls Church City County
Loudoun County
Prince William County
Manassas City County
Montgomery County
Prince George's County
Charles County
Sources
Last updated: