Water Heater Replacement Cost: What Plumbers Should Charge
Water heater replacement looks like a commodity service until you're on the job and the shut-off valve won't close, the flue vent is too small for the new unit, and the expansion tank is 10 years old and needs to go. A flat-rate quote that doesn't account for these variables turns a 2-hour job into a 4-hour job at the price you quoted for 2 hours.
What Drives Water Heater Replacement Cost
Unit type and size — a 40-gallon gas tank, a 50-gallon electric, and a heat pump water heater are three different scopes. Efficiency tier (standard vs. high-efficiency) affects both unit cost and venting requirements.
Fuel type — electric is simpler: drain, disconnect, swap, refill. Gas requires flue vent sizing check, gas connection inspection, and potentially a new flex connector. High-efficiency condensing units need a different vent system than standard units.
Expansion tank — code requires an expansion tank in any closed system (most homes with a pressure-reducing valve). If you don't include one in your quote and the inspector requires it, you're eating the cost. Build it in.
Shut-off and supply valves — if the existing shut-offs are original to the home, they may not seal properly under the pressure of the work. Quote includes a valve check; if they fail, that's a billable add-on you disclosed upfront.
Permit — most jurisdictions require a permit for water heater replacement. Include the fee and inspection cost in your quote.
When Tankless Becomes the Conversation
Customers often ask about tankless during a tank replacement. The honest answer: tankless is a significantly higher upfront cost and may require gas line upsizing, new venting, and water treatment if hardness is an issue. For customers who plan to stay in the home 10+ years, the long-term cost can work. For everyone else, a high-efficiency tank is probably the better choice.
Know both options well enough to have the conversation — and know your installed cost for each so you can present it clearly.
Building a Quote That Doesn't Surprise You on Site
A water heater replacement quote should include: unit + markup, expansion tank, permit, disposal fee, and a line for "potential add-ons" (shut-offs, gas line work, vent modification) with a "will notify before proceeding" note. That disclosure protects you legally and sets clear customer expectations.
Use the Water Heater Replacement Calculator to build a complete replacement quote. Select unit type, size, fuel, permit requirements, and any add-on work — and get a full installed price with your markup included.