One of the most common plumbing-related issues in a home or apartment is a hot water heater not doing its job. Sometimes it’s a matter of a pilot light going out, which homeowners can usually relight themselves by following the manufacturer’s instructions printed on the unit. (An important word of caution: If you smell gas, do not proceed with lighting the pilot on your water heater. Instead, contact your local gas company to isolate and solve whatever the problem may be.) If the pilot light goes out frequently, it may be necessary to have a professional inspect the thermocouple, a safety device that senses when the pilot light is burning and signals the gas valve to close if the pilot light goes out. Over time, the thermocouple can get dirty and stop working because it sits in the pilot light’s flame at all times. Generally, water heater repairs cost $150–$400, depending on what’s wrong. Some repairs, such as tank leaks, may not be repairable and can signal that it’s time to replace an older water heater.
Gas versus electric
Tank-style water heaters use either natural gas or an electric coil to heat the water in the tank. Gas water heaters are less energy-efficient than electric water heaters, but the cost of electricity may make gas a better choice in some cases. Regardless of whether a water heater is gas or electric, similar problems can arise, and costs to replace the thermostat or heating element in a gas or electric water heater are usually about the same. Costs differ primarily when installing brand-new gas or electric units.
Kenny Lowenthal, owner of Major Appliance Repair in the Jacksonville, Florida, area, says the two most common water heater malfunctions he encounters require replacing either (or sometimes both) a thermostat or a heating element. Most standard electric water heaters have two thermostats and two elements. Lowenthal charges $185 to replace a bad thermostat and $200 to replace the thermostat and heating element. Ben Goheen, owner of Precision Plumbing in Winder, Georgia, near Atlanta, says another common problem is a bad (or corroded) thermocouple. Here are average costs to repair or replace a few common water heater problems:
Clean and repair thermocouple: $395
Replace thermostat and/or heating element: $150–$200
Leaks: Generally not affordable to repair, unless the unit is still under warranty
Repair versus replace
Deciding whether to repair or replace a malfunctioning water heater starts with its age. A traditional tank-type water heater lasts about eight to 12 years. An anode rod inside the tank helps protects the interior lining by attracting corrosive particles to itself through electrolysis. Over time, the rod corrodes and can’t do its job. At that point, corrosion inside the tank will start to occur, signaling the end of the unit’s life. The most common signs of this are discolored or rust-colored water and a metallic or otherwise "off" odor or taste. Tankless water heaters last up to 20 years, but they also cost two to three times more. Goheen of Precision Plumbing charges $1,000 to replace a 50-gallon tank-style electric water heater (not including any upgrades required by building codes). Replacing a gas-powered water heater costs $1,100 (not including code upgrades). Water heater manufacturers typically do not warranty units for longer than six years because they know that’s when they may start to malfunction or fail. A unit with a six-year warranty can usually be expected to last eight to 10 years, Goheen says. Tank leaks most often signal that a unit needs to be replaced, he says, especially if it is more than six to eight years old.