The water heater library · Independent · Sourced
Should I repair or replace my water heater? What it costs
Repair a tank that is under about 6 to 8 years old when one part has failed. Replace it when the repair would cost more than 50% of a new unit, or when the tank itself leaks. Tank replacements commonly run $600 to $3,100 installed, and tankless installs $1,400 to $5,600 (2026 national ranges).
- Guides
- 64
- Cited sources
- 476
- Updated
- Oct 2026
The library
Every number is sourced
Costs, codes and lifespans link to the agency, standard or manufacturer they came from, with the date we checked.
Dated and corrected
Each page shows when it was last reviewed. Send a correction and we review safety and legal issues within 2 business days.
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What this library covers
Water Heater Facts is a learning library for homeowners. Each page answers one question, cites the manufacturer, the government agency or the code that backs it up, and says plainly when a job belongs to a licensed plumber. We are an information site run by Strive LeadGen LLC. We are not a plumbing company, and we can connect you with an independent licensed plumber if you want one.
The library has five working parts:
- Troubleshooting: symptom pages for no hot water, leaks, noises, smells and pilot problems, each split into safe homeowner checks and pro-only work.
- Error codes: plain-English tables for Rinnai, Navien and Rheem tankless codes, paraphrased from the makers' service documents.
- Repair or replace: the age and cost math, plus how long each type lasts.
- Costs and buying guides: dated price ranges from named sources, sizing, and tank vs tankless.
- Age decoder: read the build date off your serial number.
How to use it
- Find the age first. Most repair or replace decisions turn on age. A tank past 10 years is a different decision from a 4-year-old tank with a bad part[1].
- Match your symptom. Start at the troubleshooting page for what you see or hear. Each one lists what you can safely check and where to stop.
- Check the cost math. If a repair quote is more than half the price of a new unit, Rheem's guidance is to replace[1].
One more thing to know before you shop: the 30% federal tax credit (25C) does not apply to water heaters placed in service after December 31, 2025[3]. Many older articles still say it does.
The three most common problems
- No hot water from a gas tank: usually gas supply, the pilot or ignition, or a safety lockout.
- Leaking from the bottom: could be the relief valve, the drain valve, condensation, or a failed tank. Only the last one forces a replacement.
- Relief valve dripping: often thermal expansion, which a plumber fixes with an expansion tank, not a plug.
If you smell gas, skip this site: leave the house and call your gas utility or 911 from outside.
When to call a pro
- Any gas smell, scorch marks, or a relief valve releasing hot water or steam.
- Water coming from the tank body itself.
- Any repair behind a sealed panel, on a gas valve, or on wiring.
- A replacement: many cities and counties require a permit and inspection for it, and some let only a registered plumber pull that permit.