What to Expect When You Replace a Water Heater (Without the Sales Pitch)
Replacing a water heater isn’t fun. It usually happens because something broke, started leaking, or just got too unreliable. And when the hot water’s out, nobody wants to waste time figuring out what comes next.
Here’s a clear look at what really happens when you replace a water heater—whether it’s gas or electric, tank or tankless. No pressure, no upsells. Just the real process, step by step. Hot Water Heater Pros is the best water heater installation company when you have issues with your water heater or something else related to this.
What to expect from the process
Step 1: Diagnosis and Quote
First, a technician checks out the current unit. They’ll figure out what kind of system you have, how it’s vented, what size it is, and whether it’s even worth trying to repair.
If replacement is the smart call, you’ll get a quote. That usually includes:
- Removal of the old unit
- Installation of the new one
- Any code upgrades or parts needed (like expansion tanks or venting)
- Labor
- Cleanup and haul-away
There may also be optional add-ons—like a pan, insulation, or longer warranty—but those shouldn’t be pushed unless they actually make sense for your setup.
Step 2: Shutting Down the System
Before anything gets swapped, the tech will shut off power or gas to the heater. Water supply gets cut too. Then the tank gets drained completely—usually through a hose to a nearby drain or outside.
For gas models, this step includes turning off the gas line and disconnecting the flue or exhaust pipe. Electric ones are simpler—just kill the breaker and unhook the wiring.
Step 3: Removal of the Old Heater
Once everything’s shut off and drained, out it goes.
Older tanks can be heavy, especially with sediment buildup inside. If space is tight, this step might take longer. But in most cases, pros can remove a standard tank in under an hour.
If there’s visible water damage around the area—rotting wood, rust, mold—that’ll be flagged before the new one goes in.
Step 4: Prepping the New Install
This is where things can vary.
If your new heater is the same type and size as the old one, it’s usually a simple swap. But if you’re changing fuel types, going tankless, or upgrading to a larger unit, the prep can take longer.
This step includes:
- Setting the new unit in place (or mounting it, in the case of a tankless unit)
- Connecting water lines
- Hooking up the gas or electrical connections
- Installing new venting if needed
- Adding a pressure relief valve and drain line
- Making sure it meets local code
In some cases, upgrades like seismic straps, drain pans, or expansion tanks are now required—even if the old setup didn’t have them.
Step 5: Testing Everything
Once it’s all connected, the tech will:
- Fill the tank
- Bleed out air from the water lines
- Check for leaks
- Turn on the gas or power
- Make sure the thermostat is working
- Confirm the unit fires up and heats correctly
If anything’s off, they’ll fix it on the spot. No one should leave without confirming you’ve got hot water and no leaks.
Step 6: Cleanup and Walkthrough
A good tech won’t leave a mess. The old heater gets hauled away, packaging gets tossed, and the space gets wiped down.
Before leaving, they should walk you through:
- How the new unit works
- Where to check the temperature setting
- How to turn it off in case of emergency
- When to schedule the first maintenance
If it’s a gas model, you might also get tips on checking the pilot light or what to do if it goes out.
How Long Does It All Take?
From arrival to final test, a standard water heater replacement takes about 2–4 hours. More if there are surprises (tight space, outdated parts, code changes), less if it’s a straight swap.
What About Permits and Inspections?
In many parts of Tennessee, water heater replacements require a permit and a follow-up inspection. A licensed plumber usually handles this, but it’s worth asking ahead of time so there are no surprises.
Replacing a water heater isn’t a glamorous project. But it doesn’t have to be a nightmare either. With the right prep—and someone who knows what they’re doing—it’s just a half-day of work and a much more comfortable home.
