Water Heater Not Working: Repair Costs and When To Replace

Which part died decides the bill

Cold shower this morning? Here's the number you came for: a professional repair on a tank-style unit typically runs $228–$1,017, and where you land in that spread depends almost entirely on which part died. Relighting a pilot assembly barely dents the low end. A failed gas control valve is what pushes a bill toward the top. One thing changes that math. If water is pooling under the tank or standing in the drain pan, you're not looking at a repair at all: a corroded tank can't be patched, and a standard swap runs $600–$2,500 installed. The guides land in different parts of that spread — HomeGuide puts a leaking-tank replacement at $600–$1,800, Angi at $850–$1,800, and NerdWallet prices a standard 40- to 50-gallon unit at $1,200–$2,500. Everything below assumes your floor is dry.

The breaker, the reset button, and a flashlight

Plenty of no-hot-water calls end with a technician pressing a button and charging a trip fee for the privilege. These checks take a few minutes.

• Electric heater? Start at the breaker panel. A tripped 240-volt breaker is the most common reason hot water vanishes overnight.
• Behind the upper access panel there's a high-limit reset button. Cut power at the breaker before you open anything.
• On gas: is the pilot lit, and is the supply line shutoff all the way open? Relighting steps are printed on the tank label.
• Confirm nobody dialed the thermostat down. It belongs near the commonly recommended 120°F.
• Take a flashlight and look underneath. Dampness, rust streaks, a crusty ring at the base.

Part by part, from the pilot to the control valve

Gas units fail at the pilot, the burner, or the valve feeding them. Electric units fail at an element or a thermostat. One job here is genuinely DIY: an anode rod is $20–$50 in parts if you have clearance above the tank. Gas work is not the place to save money.

• Thermocouple, gas: $100–$325. It's the sensor that proves the pilot is lit before gas flows, and the most common gas repair there is.
• Pilot light service call: $50–$150. Someone relights it, cleans the assembly, and leaves.
• Pilot burns steady but the main burner never fires? Suspect the gas control valve: $150–$550, parts and labor.
• Thermostat, electric: $150–$200 installed.
• Lukewarm water that runs out fast usually means a burned-out heating element, $200–$300 on an electric unit.
• Rusty water or a rotten-egg smell says the anode rod is spent. A plumber charges $150–$350 to swap it.
• T&P relief valve: $50–$300. When the valve that vents excess pressure drips nonstop, it's finished.

Gas hides its failures at the base of the tank

Electric heaters are simple machines. Tripped breaker, burned-out element, bad thermostat — cheap parts, quick swaps, which is why electric repairs cluster in the lower half of that range. Gas is where the money hides. Almost everything that goes wrong on a gas unit sits in the same cramped space at the base of the tank, and the control valve down there isn't cheap. It's also the one place you don't improvise: gas valve and burner work belongs to a licensed plumber, not to a Saturday afternoon and a video. Staying with the fuel you already have keeps the job simple. Switching adds gas line, venting, or electrical work on top.

The most expensive decision is when you call

Labor dominates any small repair. Plumbers commonly charge $75–$150 an hour, which is Fixr's national average; HomeGuide's wider national spread runs $45–$200. Add a $50–$250 service or trip fee on top, and figure one to two hours for most swaps. The clock is the part you control. After-hours calls carry a $150–$300 service fee — HomeGuide stops at $250, Angi runs to $300 — weeknight emergency work often runs about 1.5 times standard pricing, and weekend or holiday calls can hit 2–3 times standard rates. Same thermocouple, same hour, double the invoice, because the pilot went out on a Saturday night.

• No hot water, dry floor, nothing smells off? Shut it down and book a weekday morning.
• Smell gas? Everyone out of the house, then call the gas utility, not a plumber.

The date on the label decides most of this

Tank water heaters typically last 8–12 years, and the age of yours decides most of what follows. The manufacture date sits on the label near the serial number; find it before you agree to anything. Under 8 years old, repair is almost always right, and the part may still be under warranty even when labor is not. In the 8-to-12 window a $100–$325 thermocouple is still money well spent, but a $150–$550 control valve deserves a hard look, because the odds of the shell letting go climb every year. Past 12, most plumbers quote a replacement alongside any significant repair. That's not a sales tactic. That's the math. There's a rule of thumb worth knowing before you approve anything big: Bob Vila puts the line at 50% — once a repair costs half of what a new heater would, you're paying to postpone the same decision.

Three situations where replacement isn't a close call

Three situations decide it, and none are close calls. A new unit also resets the warranty clock and heats better than a 10-year-old tank packed with sediment.

• The tank is leaking. Once the steel shell corrodes through there's nothing to fix, and a swap runs $600–$2,500.
• A big repair on an old unit. When the quote reaches roughly half the cost of a new heater, replacement wins, especially past the 8-year mark.
• Service call after service call. Each one small, the total quietly passing what a new tank cost.

Ask for both numbers on one page

Get a second quote if you have time, and ask each company to price the repair and the replacement side by side, in writing. A company that only wants to sell you a tank goes vague when you ask for both numbers on one page. That's your answer.

• Give the dispatcher symptom, fuel type, tank size, and age in one breath: gas unit, about ten years old, pilot won't stay lit, floor is dry. The truck shows up with the part.
• Ask whether the trip or diagnostic fee is credited toward the repair if you approve the work.
• Then put the anode rod on a 3-to-5-year cycle: $150–$350 professionally, or $20–$50 on your own. Nothing extends tank life for less.