How Long Does Water Heater Replacement Take?
When your water heater fails, you don’t just want it fixed—you want to know how long your home will be without hot water and how to plan your day. The good news: for many homes, water heater replacement is often a same-day job.
Dyson Plumbing has served Mobile since 1952, and we replace water heaters across Mobile Bay and Baldwin County every week. Here’s the realistic timeline, what can slow things down, and how to make the process smoother.
Typical Water Heater Replacement Time
For many standard tank replacements (gas or electric), the job can often be completed in a few hours. That includes:
- disconnecting and removing the old unit
- setting and connecting the new unit
- filling, purging air, and bringing the heater up to temperature
- safety and leak testing
That’s the “normal” scenario.
What Can Add Time to a Replacement?
Some jobs take longer—not because anyone is dragging their feet, but because the system needs to be installed safely and properly.
1) Tight spaces or difficult access
Water heaters in closets, small utility rooms, attic spaces, or tight mechanical rooms can take longer simply because work has to be done carefully.
2) Venting changes (gas units)
Gas water heaters require safe venting. If the venting is damaged, corroded, improperly sized, or not up to current standards, adjustments may be required.
3) Code-related safety updates
Depending on your setup, you may need items such as:
- drain pan and proper drain routing
- expansion tank
- shutoff improvements
- relief valve discharge piping updates
These aren’t “upsells.” They’re often safety and best-practice items that help prevent leaks, pressure issues, and future headaches.
4) Piping modifications
Sometimes the new unit doesn’t line up perfectly with existing connections (especially if the old installation was non-standard). Small piping changes are common and can add time.
5) Switching to tankless
A tankless upgrade can add time if gas line sizing or venting changes are needed.
What Happens During the Replacement (Step-by-Step)
Here’s a simple overview of what we do:
- Confirm type and size (gas/electric, capacity needs)
- Shut down the system safely
- Drain and remove the old unit
- Set and install the new heater
- Connect water lines, gas/electric
- Verify safety components (relief valve, venting)
- Fill, purge air, test for leaks
- Bring the unit to temperature and verify performance
How to Help the Replacement Go Smoothly
If you want the fastest, cleanest replacement, a few simple steps help:
- Clear the area around the water heater
- Take a photo of the heater label (if you can)
- Know whether you have gas or electric
- Let us know if the heater is in a tight closet, attic, or crawlspace
What You Should Expect When It’s Done
A proper replacement ends with testing:
- no leaks at connections
- safe venting (gas)
- correct water temperature and stable performance
- a quick explanation of what was installed and what to watch for
Bottom Line
Most standard water heater replacements are often completed in a few hours. If access, venting, or code updates are involved, it can take longer—but the goal is always the same: safe, reliable hot water you can count on.
