The short answer
A water heater repair bill has two parts: the repair itself (the part plus the plumber's time) and a call-out fee for the visit. Modernize puts most repairs at $90 to $1,775, about $600 on average. HomeAdvisor's normal range is $228 to $1,017.
In plain English: a thermocouple, thermostat, element or relief valve is usually a few hundred dollars. A gas valve or anode rod can be more. A tankless heat exchanger can top a thousand. And a leak from the tank itself is not a repair at all: the heater needs replacing.
A worked example, start to finish
Say your gas water heater's pilot lights but goes out as soon as you let go of the knob. That is the classic sign of a worn thermocouple (a thin copper rod that tells the gas valve the pilot is lit). It is a weekday, you pay a call-out fee, and the heater is 6 years old. These are the calculator's default settings, so you can check every number.
- The repair, parts and labor: $150–$350 (Modernize).
- Call-out fee: $75–$200 (Modernize).
- Total: $150 + $75 = $225 at the low end, and $350 + $200 = $550 at the high end. The middle is $388: our own midpoint, not a published figure.
- A new 50-gallon gas tank heater, installed, is $950 to $1,550 on our replacement calculator (mid-range brand, average labor), so the middle is $1,250.
- The repair is 31% of a new heater, under Rheem's 50% line, and 6 years is younger than the 8 to 12 years a tank lasts. Verdict: repair it.
A harder case. A 16-year-old gas tankless heater throws an overheating code on a Saturday night, and the plumber finds a failing heat exchanger. The repair is $500 to $1,500 (Modernize, who prints “$1,500+”, so the top could be higher). The plumber waives the call-out fee, but the after-hours surcharge adds $100–$200 (Fixr). That makes $600 to $1,700, typical $1,150. A new gas tankless heater is $1,250 to $2,100 installed, typical $1,675. The repair is 68.7% of that, over the 50% line. Verdict: replace, even though 16 years is still inside the 15 to 20 years a tankless heater lasts.
repair bill = parts and labor + call-out fee + after-hours surcharge
replace if repair > 50% of a new heater, or the tank itself leaks
What common water heater repairs cost
Parts and labor, national average, before the call-out fee. These are Modernize's figures; the calculator shows HomeAdvisor's and Fixr's beside your result.
Gas tank heaters
| Repair | What you notice | Parts and labor |
|---|---|---|
| Thermocouple / flame sensor | The pilot lights but goes out when you let go of the knob. | $150–$350 |
| Pilot / igniter assembly | The pilot will not light, or the igniter clicks with no flame. | $150–$450 |
| Gas control valve | No hot water, pilot and thermocouple are fine, or the valve knob is stuck. | $250–$750 |
Electric tank heaters
| Repair | What you notice | Parts and labor |
|---|---|---|
| Heating element | Lukewarm water, or hot water runs out much faster than it used to. | $150–$350 |
| Thermostat | Water is too hot, too cold, or the temperature swings. | $100–$300 |
Any tank heater, gas or electric
| Repair | What you notice | Parts and labor |
|---|---|---|
| Anode rod | Rotten-egg smell from the hot water, or rusty-looking hot water. | $200–$500 |
| T&P relief valve | Water drips or sprays from the pipe on the side of the tank. | $150–$350 |
| Dip tube | Hot water turns lukewarm fast, or white plastic bits clog the faucet screens. | $150–$400 |
Tankless heaters (and leaks on any heater)
| Repair | What you notice | Parts and labor |
|---|---|---|
| Leak at a valve, fitting or line | Water at a pipe joint, the drain valve or a supply line, not the tank itself. | $150–$600 |
| Tankless descaling / flush | Scale error code, or the water swings hot and cold. | $150–$400 |
| Tankless sensor | An error code for a flow or temperature sensor, or the unit will not fire. | $150–$500 |
| Tankless heat exchanger | A leak inside the unit, or an overheating error that keeps coming back. | $500–$1,500 |
Repair or replace?
Rheem, a water heater maker, gives two tests. The first is cost: if a repair costs more than 50% of a new unit, replacing is almost always the better buy. The second is age: tank heaters last about 8 to 12 years and tankless heaters 15 to 20 or more, and older units are more likely to fail again soon after a fix.
The calculator applies both. It takes the price of a new heater from our water heater replacement cost calculator at its standard size, so the two pages always agree. To compare fuels or a tank-to-tankless switch, use that calculator or the water heater installation cost calculator.
The part is cheap; the visit is not
Most of a repair bill is labor and the trip. Everbilt 4500-Watt/240-Volt low-watt-density screw-in water heater element costs $18.98 at The Home Depot, and everbilt upper-element thermostat for residential electric water heaters $18.98. HomeAdvisor puts the thermostat part at about $20 against $150 to $200 installed. Electric heaters run on 240 volts, and gas valves and pilots involve gas lines, so a licensed plumber is the safe choice for anything past relighting a pilot by the instructions on the label.
What a fair quote includes
- The name of the failed part, and how the plumber tested it.
- The part price and the labor price on separate lines.
- Whether the call-out fee comes off the bill if you go ahead (Fixr says it can be waived if you hire the plumber for the repair).
- Whether the tank or part is still under the maker's warranty. Ask them to check the serial number.
- Any after-hours surcharge, stated before work starts.
- How long the repair itself is guaranteed for.
Where the publishers disagree
- Anode rod: Modernize prints $200 to $500, HomeAdvisor $50 to $150 and Fixr $125 to $300. The calculator uses Modernize's, so expect quotes below it.
- Heating element: Modernize prints $150 to $350, HomeAdvisor $200 to $300, and Fixr runs much higher at $200 to $750.
- Gas control valve: Modernize prints $250 to $750; Fixr a lower $150 to $300; HomeAdvisor about $350 on average.
- Call-out fee: Modernize prints $75 to $200; Fixr says around $50. The calculator uses Modernize's and lets you waive it.
- Tankless parts: only Modernize prices a tankless sensor and heat exchanger on their own. Fixr prints one tankless-repair band, $100 to $650.
Methodology
- All cost figures are US national and come from the sources below, each read on 18 October 2026. The cost guides are secondary sources (aggregators), dated August 2025 (Fixr), June 2026 (HomeAdvisor) and August 2026 (Modernize).
- The repair price is Modernize's band for that part, because it is the only publisher we read that prices every part here, tank and tankless. Other publishers' figures are shown beside it, never averaged in.
- Low and high come from the published bands. “Typical” is the midpoint and is our own figure.
- The after-hours option adds Fixr's $100 to $200 emergency surcharge. The call-out fee is Modernize's $75 to $200.
- The new-heater price comes from the site's water heater replacement calculator: the same fuel and type, its standard size (50 gallons for a tank, medium for tankless), a mid-range brand and average labor. The verdict compares the typical repair with the typical new heater.
- Not priced: local labor rates, warranty coverage, and a leak from the tank body (which is replaced, not repaired).
Sources
- Modernize — Water Heater Repair Cost 2026: Prices, Fix Types & Tips (Kate Pospisil, updated 12 Aug 2026; secondary cost guide). https://modernize.com/plumbing/water-heaters/repair-cost Read 2026-10-18.
- HomeAdvisor — How Much Does a Water Heater Repair Cost? (updated 17 Jun 2026; secondary cost guide). https://www.homeadvisor.com/cost/plumbing/repair-a-water-heater/ Read 2026-10-18.
- Fixr — Water Heater Repair Cost (Adam Graham, updated 29 Aug 2025; secondary cost guide). https://www.fixr.com/costs/water-heater-repair Read 2026-10-18.
- Rheem — Water Heater Lifespan: When to Repair vs. Replace (25 Mar 2026; manufacturer). https://www.rheem.com/water-heating/articles/water-heater-lifespan-when-to-repair-vs-replace/ Read 2026-10-18.
- The Home Depot — Everbilt 4500-Watt/240-Volt low-watt-density screw-in water heater element, $18.98. https://www.homedepot.com/p/Everbilt-4500-Watt-240-Volt-Low-Watt-Density-Watt-Fold-Back-Screw-In-Stainless-Steel-Alloy-Water-Heater-Element-EBEL-4500-240-INC/331674275 Read 2026-10-18.
- The Home Depot — Everbilt upper-element thermostat for residential electric water heaters, $18.98. https://www.homedepot.com/p/Everbilt-T-O-D-Style-Upper-Element-Thermostat-for-Non-Simultaneous-Design-Residential-Electric-Water-Heaters-EBTSTAT-UP/331674093 Read 2026-10-18.
Related calculators
Pricing a new heater instead? Use the water heater replacement cost calculator. Keeping this one going longer? The water heater maintenance cost calculator prices flushing and anode checks. For other leaks and clogs, see the plumbing repair cost calculator.
Methodology & sources
The cost figures on this page are generated from a single, sourced cost-data file (One repair on a home tank or tankless water heater (gas or electric) in the United States, priced as parts plus labor from Modernize's August 2026 component bands, with the diagnostic call-out fee and any emergency surcharge shown separately. Cross-checked against HomeAdvisor (June 2026) and Fixr (August 2025); all read 18 October 2026. The new-unit price for the repair-or-replace verdict comes from the site's water heater replacement calculator.). Modernize puts a water heater repair at $90 to $1,775, about $600 on average; HomeAdvisor's normal range is $228 to $1,017 (average $616) and Fixr's $150 to $750. Small parts such as a thermocouple or thermostat sit at the bottom; a tankless heat exchanger sits at the top, where repair-or-replace becomes the real question. Last verified October 2026.
- Modernize — Water Heater Repair Cost 2026: Prices, Fix Types & Tips (Kate Pospisil, updated 12 Aug 2026; secondary cost guide) — retrieved 2026-10-18
- HomeAdvisor — How Much Does a Water Heater Repair Cost? (updated 17 Jun 2026; secondary cost guide) — retrieved 2026-10-18
- Fixr — Water Heater Repair Cost (Adam Graham, updated 29 Aug 2025; secondary cost guide) — retrieved 2026-10-18
- Rheem — Water Heater Lifespan: When to Repair vs. Replace (25 Mar 2026; manufacturer) — retrieved 2026-10-18
Frequently asked questions
How much does it cost to repair a water heater?
Most repairs cost a few hundred dollars. Modernize puts water heater repair at $90 to $1,775, about $600 on average. HomeAdvisor's normal range is $228 to $1,017, and Fixr's is $150 to $750. A tankless heat exchanger is the most expensive common repair.
How much does it cost to replace a thermocouple on a gas water heater?
Modernize puts a thermocouple replacement at $150–$350, parts and labor; HomeAdvisor says about $150 and Fixr $150 to $325. Add a call-out fee of $75–$200 and a weekday visit comes to $225–$550, with $388 as the middle of that range.
How much does it cost to replace a heating element in an electric water heater?
Modernize prints $150–$350 for a plumber to replace a heating element, HomeAdvisor $200 to $300 and Fixr $200 to $750. A 4500-watt replacement element costs $18.98 at The Home Depot (read 18 Oct 2026); most of the bill is labor.
Should I repair or replace my water heater?
Rheem's rule of thumb: if a repair costs more than 50% of a new unit, replacing is almost always the better buy. Rheem says tank heaters last about 8 to 12 years and tankless heaters 15 to 20 or more. A leak from the tank body itself cannot be repaired.
Do plumbers charge more for an emergency water heater repair?
Yes. Fixr says emergency repairs add $100 to $200 to the bill. The calculator adds that as a flat surcharge to the repair and the call-out fee.
How much does tankless water heater repair cost?
Fixr puts tankless repair at $100 to $650 (gas $150 to $650, electric $100 to $600). Modernize prices descaling at $150–$400, a sensor at $150–$500 and a heat exchanger at $500 to $1,500 or more.