If the tank is leaking, do these three things first
Water coming from the base of the tank, the seams or the tank body means the steel has failed. Turn off the cold water supply valve on top of the heater. Switch the heater off at the breaker or turn the gas control to the pilot or off setting. Shut off nothing else you do not need to.
Water from the pipe on the side of the tank near the top is the temperature and pressure relief line. That one is a safety device that is doing its job and needs a plumber, not a mop. If you smell gas, leave the house and call the gas utility or 911 from outside before you call us.
What can be repaired and what cannot
A leaking tank body cannot be patched. The failure is rust-through of the steel, and the answer is water heater replacement. Most other faults are repairable.
| Fault | Usual cause | Usual outcome |
|---|---|---|
| No hot water, gas model | Pilot out, thermocouple or gas control failure | Repair |
| No hot water, electric model | Failed element, thermostat or tripped limit | Repair |
| Water too hot or too cool | Thermostat setting or failed thermostat | Repair |
| Rumbling or popping noise | Sediment layer on the tank floor | Flush, may be repaired |
| Dripping from relief valve | Valve worn, or pressure too high | Valve replacement, check expansion tank |
| Leak from tank body | Rust-through | Replacement |
How the diagnosis goes
- Safety check. The plumber checks gas, venting, electrical supply and water leaks before touching the unit.
- Find the failed part. Meters and a visual check isolate whether the problem is the burner, the control, an element or the tank.
- Weigh repair against replacement. On a heater near the end of its life, a repair bill beside a new unit's price is a real decision, and you hear both numbers.
- Fix, test and clean up. The plumber tests temperature, checks the relief valve and leaves the area dry.
If a heater is old and needs more than a simple part, the honest advice is often to replace it. Age is on the tag, in the serial number, and the plumber can decode it.
No hot water or a leaking tank? Call the 24/7 line.
Call (650) 860-1670What affects the price of a water heater repair
- The part that failed. A thermocouple, element or thermostat is a smaller repair than a gas control valve.
- Gas or electric. The two types use different parts and different tools.
- Tank age. Parts for an older unit can be harder to source, and a repair may not be worth it.
- Access. A unit in a closet or attic takes longer to service than one in an open garage.
- Time of call. After-hours emergency dispatch costs more than a booked visit.
Many homeowner's policies cover sudden water damage from a failed tank but not the heater itself, and wear and tear is excluded. Photograph the unit and the water before cleanup. You get the price before the plumber starts.
Gas, electric and hybrid heat pump water heaters
The repair depends on the type of heater. A gas tank has a burner, a thermocouple and a vent that need care. An electric tank uses heating elements and thermostats that fail one at a time. A hybrid heat pump unit adds a compressor and fan, plus a condensate drain that can clog and leak.
Tell the dispatcher which kind you have and read us the model label if you can. Hybrid units are quieter to troubleshoot when you know the error code on the display. If you smell gas, leave the building and call the gas utility or 911 from outside before you call us.
Water pressure and the relief valve
The City of Mountain View's water FAQ says the system delivers an average minimum pressure of 45 pounds, above the state's 25-pound requirement. The City does not publish what your street runs at the high end. Pressure that is too high can make a relief valve weep and shorten the life of a heater, so a plumber who finds a dripping valve should also check pressure and the expansion tank before blaming the valve alone.
Water heater connections are covered by the California Plumbing Code, so a repair that touches them should leave the installation as that code expects.
Water Heater Repair questions
Is emergency water heater repair available at night in Mountain View?
Yes. Call (650) 860-1670 at any hour. A licensed plumber is dispatched for leaks and for no-hot-water calls.
Why does my water heater leak at the bottom?
Usually the tank has rusted through, which is not repairable. Turn off the cold supply and the power or gas, then call. If the water is from a valve or a pipe fitting, it may be a repair.
Is it worth repairing an older heater?
It depends on the age and the part. A simple part on a heater in good shape is worth fixing. A large repair on a heater near the end of its life usually is not. The plumber gives both numbers.
My pilot light keeps going out. Is that dangerous?
A pilot that will not stay lit points to a failed thermocouple, a draft or a gas control problem. If you smell gas, leave and call from outside. Otherwise call for a repair.
Do you repair tankless heaters?
Yes. Error codes, scale and flame sensor faults are common. See the tankless water heater page for flushing and service.