The rule: the 50% Rule, with an 8-year age limit.
If the repair quote is half or more of what a brand-new water heater costs and your unit is 8 years or older, replace it. If either number is under those lines, repair it.
Water heaters die from the inside out. Sediment piles up at the bottom, the tank corrodes, and efficiency drops every year. A cheap repair on a young unit buys you years of hot water. The same repair on a 12-year-old tank is just delaying the inevitable — and when a tank fails, it can dump 40+ gallons of water where you don’t want it.
Most standard tank heaters last 8–12 years. If yours is tankless, it can run 15–20 years, so swap the 8-year line for 15.
One exception that skips the math: if the tank itself is leaking, repair isn’t an option. It has to be replaced.
Educational estimate only. Based on YOUR repair quote, cost of a new water heater installed, and age of your current unit in years you enter. Uses 50% Rule with 8-year age limit: if repair is half or more of new AND unit is 8+ years old, replace it. If either number is under those lines, repair it. Standard tank lasts 8-12 years, tankless 15-20 years so swap 8-year line for 15 if tankless. Tank itself leaking = replace, no math needed.
Disclaimer: Educational only, not professional advice. Get quotes from licensed, reputable contractors.
Frequently Asked Questions
What is the 50% rule for water heaters?
If the repair quote is half or more of what a brand-new water heater costs and your unit is 8 years or older, replace it. If either number is under those lines, repair it.
When should I replace instead of repairing?
If the tank itself is leaking, repair isn’t an option — it has to be replaced. Also replace if repair is over $500 or the unit is 12+ years old.
How long do water heaters last?
Most standard tank heaters last 8–12 years. If yours is tankless, it can run 15–20 years, so swap the 8-year line for 15.
When should I ignore this rule and talk to a professional?
This is educational only, not professional advice — get quotes from licensed, reputable contractors.
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