Many Falls Church homes date to around 1971, so tankless heaters here often run on gas pipe and vents that were not designed for them, and scale from moderately hard Fairfax Water slowly cuts their flow. Inside the City, permits come from the Department of Code Administration. Call the number on this page to be connected with a local plumber in Falls Church.
Falls Church at a glance
The City of Falls Church is a small independent city where Route 7 and Route 29 meet. About half its homes were built before 1971. Fairfax Water supplies the water, the City runs its own sewers, and Washington Gas supplies gas. The Falls Church mailing area reaches well beyond the City into Fairfax and Arlington counties, including Seven Corners, and those addresses follow county rules. City sewage flows to two treatment plants, Arlington County's and Alexandria's, which matters only when a condensate or relief line is being routed to a floor drain. Many tankless units in the City were installed during renovations of mid-century houses, so their gas supply and venting are worth checking whenever they misbehave.
What to do now
- Note the error code and the unit's model and install date.
- Check that the unit's outlet and breaker are on.
- Open a single hot tap all the way to rule out a minimum-flow issue.
- Look at the vent and intake outside for blockages.
- If you smell gas, leave the house, then call 911 and Washington Gas at 844-WASHGAS (844-927-4427), option 1, from outside.
Symptoms and what usually causes them
| Symptom | Usual cause |
|---|---|
| Water turns cold with two showers on | Gas pipe or unit too small for the load |
| Steady loss of flow | Scale in the heat exchanger |
| Burner lights then drops out | Flame sensor, gas pressure or vent issue |
| Rattling vent or whistling | Loose vent section or obstructed termination |
| Leak under the unit | Fitting, relief valve or condensate line |
Cost factors
- Flushing and sensor work versus a major part on an older unit
- Gas pipe upsizing in homes built for a tank and furnace
- Venting changes, especially where the old tank used a chimney
- Permits: inside the City, the Department of Code Administration at 300 Park Avenue (703-248-5080); Falls Church-addressed homes outside the City go to Fairfax County or Arlington County
- Scale protection: Fairfax Water's Potomac plant results average about 7.5 grains per gallon of hardness
Some Falls Church homes are served Washington Aqueduct water through Fairfax Water rather than water from Fairfax Water's own plants; either way the water is moderately hard, so isolation valves and a yearly flush are worth having. If the plumber finds a failing heat exchanger on an older unit, ask for a replacement price alongside the repair.
Tankless Water Heaters questions in Falls Church
My tankless unit keeps showing error codes. Repair it or replace it?
Is a permit required to put in a tankless water heater here?
What causes a blast of cold water partway through a shower?
How hard is the water here, and how often should the unit be flushed?
More plumbing services in Falls Church
Tankless Water Heaters nearby
Helpful guides
Sources
- City of Falls Church: Code Administration
- City of Falls Church: new resident checklist
- City of Falls Church: sewer
- Fairfax Water: Corbalis plant finished water analysis
- Fairfax Water annual water quality report
- Washington Gas: safety and the emergency leak line
- Falls Church housing by year built (city-stats.com)
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