What should a water heater replacement cost?

A standard 40–50 gallon tank water heater replacement, like-for-like, typically runs $1,200–$2,500 installed, including the unit, labor, and basic code-compliance updates (strapping, expansion tank if required).

A tankless conversion runs considerably higher — usually $3,000–$6,500 — because it often requires new gas line sizing, venting changes, and sometimes an electrical upgrade, on top of the unit itself costing more than a tank model.

Cost drivers to ask about specifically: whether your existing unit is up to current code (older installs often aren't, which adds cost to bring current), whether the water heater is gas or electric, and how accessible the install location is (a garage swap is cheaper than a tight attic or closet install).

Get a written, itemized quote rather than a single lump number — a reputable plumber will separate the unit cost from labor and any code-compliance add-ons, so you can see what you're actually paying for.