The two published rules
| Source | Rule | Date |
|---|---|---|
| Fixr | Repair is usually worthwhile if the unit has at least half its lifespan remaining and the repair costs under 50% of replacement. Repeated issues signal it is time to replace. | January 2026 |
| This Old House | Replace when repair costs exceed more than half the replacement cost, or the unit is 10 or more years old. | June 2026 |
They agree on the money and differ on the age. Fixr's test is relative to the unit's own expected life; This Old House names a flat 10 years. With tanks lasting 8 to 12 years on both sources' figures, the two rules land in almost the same place.
What the two sides of the rule actually cost
Replacement. $900 to $3,000 installed for a typical tank, average $1,400 (Fixr, January 2026). This Old House puts the average at $1,950 and the range at $1,600 to $5,400 across all types.
Repair. $150 to $750, average $450 (Fixr, August 2025):
| Type of heater | Repair cost |
|---|---|
| Electric | $100 to $650 |
| Gas | $150 to $750 |
| Propane | $150 to $750 |
| Tankless | $100 to $650 |
| Tank | $150 to $750 |
| Hybrid heat pump | $150 to $900 |
| Solar | $150 to $900 |
Applying the 50% rule to Fixr's own average replacement cost of $1,400 gives a break-even of about $700. Almost every repair in the table above falls below it. That is the useful finding on this page: on published averages, most single repairs are worth doing, and the decision usually turns on age and on which part failed rather than on the arithmetic.
The decision, by failed part
This is the table to use. Repair costs from Fixr (August 2025), compared against the $700 break-even derived above.
| What failed | Cost | Verdict |
|---|---|---|
| Leaky valve, minor adjustment | from $50 | Repair |
| Fuse | $50 to $75 | Repair |
| Pilot light, relight or thermocouple adjustment | $75 to $175 | Repair |
| Valve repair | $75 to $150 | Repair |
| Thermostat repair | $75 to $150 | Repair |
| Supply hose | $75 to $200 | Repair |
| Thermostat replacement | $100 to $250 | Repair |
| Dip tube replacement | $100 to $250 | Repair |
| Circuit breaker fault | $100 to $225 | Repair |
| Anode rod replacement | $125 to $300 | Repair, and it extends the tank's life |
| Valve replacement | $100 to $300 | Repair |
| Thermocouple replacement | $150 to $325 | Repair |
| Heating element or coil | $200 to $750 | Repair if the unit is under about 8 years old |
| Pump | $350 to $800 | Borderline, check the age first |
| Tank or cylinder repair | $250 to $1,000 | Borderline to replace |
| Tank replacement | $600 to $2,000 | Replace the whole unit |
On the last line both sources are blunt. Fixr writes that tank replacement costs are sometimes so high that a new heater is better value, and that corrosion inside a tank cannot be undone. A rusted-through tank is the end of the appliance.
The signs that override the arithmetic
Both sources list the same warning signs. When these appear, replacement is the answer regardless of what the individual repair costs:
- Water pooling at the base. Fixr names this as corrosion or a cracked tank. It is not a repair, it is a failure in progress.
- Rust-coloured water or a sulphur smell. Internal corrosion (Fixr).
- Rumbling or clinking during operation. Sediment build-up, which reduces efficiency and can signal internal damage (Fixr).
- Rising utility bills with no change in use. The unit is losing efficiency (both sources).
- Repeated repairs. Fixr states this directly: repeated issues mean it is time to replace.
The argument for replacing early
This Old House makes a point neither the repair cost nor the replacement cost captures: replacing before the unit fails prevents flooding and property damage. It prices water damage repair from a failed unit at $500 to $2,500, and emergency or after-hours service at $200 to $500 on top of a normal installation.
Our arithmetic, stated as such: a planned replacement at the $1,400 average against an emergency one at $1,400 plus $200 to $500 in emergency labor plus a possible $500 to $2,500 in water damage means a failure can cost two to three times a planned swap. Neither source adds the figures up this way. It is the strongest case for replacing a tank that is past 10 years rather than nursing it through one more repair.
What a repair visit should tell you
Ask the technician for three things before authorising work: the age of the unit from its serial number (our water heater age decoder reads the date code), what exactly failed, and whether the tank itself shows corrosion. With those three you can apply either published rule yourself in about a minute.
Related: how long a water heater lasts, anode rod replacement cost, replacement cost calculator.
Sources
- Fixr, Water Heater Repair Cost, updated August 29, 2025
- This Old House, How Much Does Water Heater Installation Cost? (2026), updated June 17, 2026
- Fixr, How Much Does a Gas Water Heater Cost in 2026?, updated January 30, 2026
Price figures are national US ranges from the sources above as of the date shown. Your local price depends on labor rates, permits and site conditions. Read how we get our numbers.