Derwood water heaters usually call for a part, a flush or a valve rather than a new tank, and a plumber can tell which after a look. A tank seeping through its own wall has to be replaced. Call the number on this page to be connected with a local plumber in Derwood.

Derwood is a suburban pocket between Rockville, Gaithersburg and Olney, and its housing came largely in one wave: about two-thirds of homes were built in the 1980s, with a median year built around 1985. That means a lot of neighbors are dealing with the same thing at roughly the same time, heaters that have already been replaced once and are now aging again. WSSC Water supplies water and sewer here; its report lists residual chlorine, UV disinfection at its plants and orthophosphate added to control corrosion. The region's moderately hard water leaves a slow build-up of sediment in tanks, which is behind a lot of the noise and short hot water people notice.
What to do now
- Shut the cold-water inlet valve if you see water around the tank.
- Switch off the breaker for an electric unit, or turn the gas control to off.
- If you smell gas, go outside before anything else, then call 911 and Washington Gas at 844-WASHGAS (844-927-4427), option 1.
- Run a towel or wet vac around the base so you can see where fresh water is appearing.
- Write down the model, serial number and fuel type from the label.
Symptoms and likely causes
| Symptom | Likely cause |
|---|---|
| Water only lukewarm | Failed element or thermostat, gas burner issue |
| Hot water runs out early | Sediment, broken dip tube |
| Crackling or knocking | Scale and sediment on the tank bottom |
| Drip from the overflow pipe | Relief valve wear, high pressure or no room for expansion |
| Brown or rusty hot water | Depleted anode, internal corrosion |
| Wet floor near the heater | Fitting, drain valve or tank leak |
Cost factors
Because so many Derwood houses went up in the same decade, plumbers here see the same heater layouts again and again, which can make diagnosis quick. What changes the bill is mostly what turns up once the tank is opened and drained:
- The failed part and whether it's in stock
- Time spent flushing a heavily sedimented tank
- Stiff valves or corroded nipples that need replacing
- Access in a basement, garage or closet
- Whether the tank needs replacing, which in Montgomery County brings a WSSC Water permit and, for gas units, a plumber or gasfitter registered with WSSC
Water Heater Repair questions in Derwood
Does my water heater need a thermal expansion tank?
What causes popping or rumbling inside the tank?
Is it worth repairing a water heater that is more than 10 years old?
What should I do if I smell gas near the water heater?
More plumbing services in Derwood
Water Heater Repair nearby
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