How long does it take to replace water heater?

This task typically takes 4-8 hours to complete, depending on your experience level and the specific conditions of your water heaters plumbing system.

What tools do I need to replace water heater?

You'll need the following tools: Pipe wrench, Gas leak detector, Teflon tape, Dolly. Make sure all tools are in good condition before starting.

Is this task suitable for beginners?

This task is rated as Professional difficulty. This task requires professional expertise and should only be attempted by licensed plumbers.

All guides

Water HeatersAdvanced

Replace Water Heater

Time

240–480 min

Steps

Pre-check

5 items

Skill

Advanced

Scope

Remove an old tank water heater and install and commission a new gas or electric unit, with proper water, fuel, and venting connections plus a full leak test.

Safety

Read before starting

Shut off gas/power and water; verify no gas leaks; follow manufacturer and local code; permit may be required.

Pre-Check

5 items · complete before you start

Fuel type matches (gas vs electric) and circuit/breaker capacity sufficient
Required
T&P relief valve discharge to code-compliant drain path
Required
Earthquake straps/pan/drain (where required) on hand
Required
Combustion air and venting (gas) meet manufacturer requirements
Required
Shutoff valves operate; drain hose reaches safe drain location
Required

0 / 36 complete

Secure Utilities & Prep

Turn off breaker (electric) or set gas valve to OFF
Close cold water inlet valve
Attach hose to drain; route to safe drain
Open hot water faucet to relieve pressure

✅Continue Gate:Power/gas off and pressure relieved?

Drain and Disconnect

Open drain valve; drain tank fully
Disconnect gas flex/electrical whip (as applicable)
Disconnect vent (gas) and water connections

✅Continue Gate:Tank empty and all lines disconnected?

Remove Old Tank

Remove straps and pan connections
Two-person lift or dolly removal
Inspect platform/pan and floor condition

Place New Tank

Position pan and tank with clearances per manual
Align T&P discharge, vent (gas), and water connections
Install earthquake straps (where required)

✅Continue Gate:Clearances and orientation correct?

Connect Water

Install dielectric unions if needed
Connect cold inlet and hot outlet with proper fittings
Use thread sealant/tape per fitting type

✅Continue Gate:Joints aligned; no cross-threading?

Venting (Gas)

Rebuild vent with proper slope and materials
Maintain required clearances
Secure joints with listed connectors

✅Continue Gate:Venting secure and code-compliant?

Fuel/Electrical

Gas: connect flex with approved sealant; leak-test with soap solution
Electric: connect whip per wiring diagram; verify ground/bond

✅Continue Gate:No gas leaks; wiring correct?

Fill and Purge Air

Open cold inlet
Open nearest hot faucet until steady flow (no sputter)
Check for leaks at all joints

✅Continue Gate:Tank full; air purged; joints dry?

Commissioning

Restore gas/power
Set thermostat (120°F typical)
For gas: follow lighting/ignition procedure and verify flame characteristics
Verify T&P valve operation briefly

✅Continue Gate:Heat source active; normal operation observed?

Finalize & Educate

Label shutoffs and breaker
Review maintenance (anode check, flushing schedule)
Document install date, model/serial

Scope

Safety

Pre-Check

Steps

Related guides