Replacing a standard tank water heater runs about $1,200–$3,500 installed in most of the US. Tankless units cost more up front — roughly $3,000–$5,500 — but last longer and never run out of hot water.
What affects the price
Type
Tank is cheaper to install; tankless costs more up front but lasts 20+ years.
Fuel
Gas units cost more to install (venting, gas line) than electric.
Tank size
A 40-gallon costs less than an 80-gallon.
Code upgrades
Expansion tank, new venting, and a permit add cost on older homes.
Cost breakdown
National-average planning ranges — your local pricing varies by region, scope, and access.
DIY or hire a pro?
Gas lines, venting, and permits make this a licensed-plumber job in most areas — not a DIY swap.
Estimating this job?
Use the free size your water heater, then turn it into a priced quote your customer can approve with the free estimate generator.
FAQ
How much does it cost to replace a 40-gallon water heater?
About $1,200–$2,000 installed for a standard gas or electric tank, including labor and disposal of the old unit.
Is a tankless water heater worth the extra cost?
Tankless costs more up front ($3,000–$5,500) but lasts about twice as long, saves standby energy, and never runs out — often worth it for a full-time household.
How long does a water heater last?
A tank heater lasts 8–12 years; a tankless unit 20 or more with maintenance. Replace before failure to avoid water damage.