In the City of Fairfax, where much of the housing dates from the 1960s, a leaking or worn-out water heater is usually replaced rather than repaired. Inside city limits, plumbing permit applications go to the City's Code Administration, while Fairfax-addressed homes in unincorporated Fairfax County use the County's Land Development Services. Call the number on this page to be connected with a local plumber in Fairfax.

Fairfax in brief
The City of Fairfax is an independent city and still the county seat, with an Old Town core and suburban neighborhoods around it. Most of ZIP codes 22030 to 22033 outside city limits is unincorporated Fairfax County. Water comes from Fairfax Water across both, with total hardness at its Corbalis plant around 70 to 185 mg/L, averaging about 7.5 grains per gallon. Housing data puts the median home at 1967, so many heaters sit in basements with older valves and flues.
What to do now
- Close the cold-water valve feeding the heater if it's leaking.
- Turn the gas control off or flip the breaker for an electric unit.
- If you smell gas, leave the house, then call 911 and Washington Gas at 844-WASHGAS (844-927-4427), option 1, from outside.
- Find the main shutoff in case the heater valve won't close; older gate valves often stick.
- Check the label for the size, fuel and year.
- Confirm whether your address is in the city or the county, since that decides the permit office.
Signs and likely causes
| Sign | Probable cause |
|---|---|
| Water under the tank | Tank failure or a leaking fitting or relief valve |
| Hot water runs short | Sediment buildup or a failing element or burner |
| Rust-colored hot water | Worn anode rod or corroding tank lining |
| Soot or a yellow flame | Venting or combustion problem; call a plumber promptly |
| Rumbling | Sediment on the tank floor |
Cost factors
- Fuel, size and efficiency of the new heater
- Permit: City Code Administration inside city limits; in the county, a Household Appliance permit for like-for-like gas swaps, with Chimney Vent Certification for fuel-burning appliances, or a Residential Plumbing permit if new gas piping is added
- Flue, valve or connector updates in 1960s homes
- Basement access, expansion tank and drain pan
- Haul-away of the old tank
Inside the city, sewer service comes from the City's Public Works department, with an after-hours line at 703-385-7924 if a floor drain backs up during the work.
In many houses of that era, the water heater vents into a chimney it once shared with the furnace. If the furnace has since been replaced with a high-efficiency unit that vents out the side wall, the water heater may be left alone in a flue sized for two appliances, which is something the installer should check before the new heater is connected.
Water Heater Replacement questions in Fairfax
Does replacing a water heater here need a permit?
How do I find out who supplies my water?
The old heater leaked in the basement. What should I check?
Will the new heater need an expansion tank or a drain pan?
More plumbing services in Fairfax
Water Heater Replacement nearby
Helpful guides
Sources
- City of Fairfax plumbing permit application
- City of Fairfax wastewater services
- Fairfax County Land Development Services: household appliance permits
- Fairfax Water: Corbalis plant finished water analysis
- Fairfax County: utility providers
- Fairfax County Wastewater Management
- Fairfax housing by year built (city-stats.com)
- Washington Gas: safety and the emergency leak line
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