A like-for-like tank swap commonly takes a few hours of hands-on work, and many plumbers plan on roughly half a day. That is a generic range, not a promise. Your heater, your vent and your access decide the real number.
Add time if the vent needs repair, the heater is moving, the old tank leaked or a permit step has to happen first. A tankless conversion usually takes longer than a tank swap, often most of a day or more. Ask the plumber for a time window when you get your price.
What happens during the job, step by step
Here is the usual order for a tank replacement. Each step is quick on its own. The total adds up through draining, carrying and testing.
Walk-through and shutoffs
The plumber confirms the model, fuel, vent and gas valve, then shuts off the water and the gas or power to the old unit.
Drain the old tank
A full tank can take a good while to empty through a garden hose, and sediment can slow it down further.
Disconnect and remove
Gas, water and vent connections come off, and the old tank is moved out. A heavy tank in a tight spot takes two people and some care.
Set and connect the new unit
The new heater goes on a level pan or base, then water, gas or electric and vent connections are made with new parts where needed.
Fill, purge and test
The tank fills before the burner or elements come on. The plumber checks for leaks, tests the gas connection and confirms the vent draws properly.
Heat-up and walk-through
The unit needs time to bring a full tank up to temperature. The plumber explains the controls and the relief valve before leaving.
Why one job takes longer than another
| Situation | Effect on time | What you can do ahead |
|---|---|---|
| Same tank size and fuel, easy access. | Closest to the short end of the range. | Clear a path and keep pets away. |
| Rusted or incorrect vent. | Adds repair time before the new unit can run. | Mention any soot, staining or odd smells. |
| Heater in attic or tight closet. | More time to carry and set. | Tell the dispatcher where it is. |
| Seized shutoff valves. | Valves must be cut out and replaced. | Know where the main shutoff is, just in case. |
| Moving to a new location. | New gas and water runs add hours or a second visit. | Decide the spot before the visit. |
| Switching to tankless. | New venting, gas sizing and mounting. | Ask for a time window for the whole conversion. |
| Permit or inspection step. | Can add waiting time outside the install itself. | Ask the El Mirage building department what applies. |
Is the water off all day?
No. Cold water usually comes back on once the new tank is connected, and the plumber can leave the house on cold water only for a short stretch while the unit fills and heats. The part you will notice is the wait for hot water at the end.
A standard tank takes a while to recover to full temperature. If the plumber has to leave before the tank is fully hot, ask when to expect hot showers. Do not run every hot tap at once to test it, because that only drags the temperature down.
Want a plumber to look at it?
Call the 24/7 line, describe what you found and hear a clear price before work starts.
How to make the visit shorter
- Clear a path from the garage door or front door to the heater.
- Move storage, paint cans and cleaning products away from the heater area.
- Know the main water shutoff location and test that it turns.
- Write down the model sticker details if you can read them, including size and fuel.
- Decide on tank size and efficiency before the visit so the plumber is not waiting on you.
- Ask whether any permit step needs to be scheduled first.
- Plan the morning around limited hot water, including laundry and dishes.
Same-day replacement versus scheduling it
If your heater is leaking, speed matters. If it is only aging, you can pick your time.
Same-day makes sense when
- Water is leaking from the tank body and you have shut off the supply.
- There is no hot water at all and the unit is too far gone to repair.
- The heater sits over finished flooring that could be damaged.
Scheduling ahead makes sense when
- The heater works but is old, noisy or slow to recover.
- You want to compare tank types or a tankless conversion.
- A permit step or special order part is involved.
What if the plumber finds a surprise once the old tank is out?
It happens. A vent that looked fine from the front may be corroded behind the draft hood, or a shutoff valve may snap when it is turned. Neither one is a reason to panic, but both add time.
Ask the plumber to stop and tell you what was found, what it adds to the work and what it adds to the price, before continuing. That is the point of getting a clear price before work starts. A short pause to agree on the change is better than a surprise on the final invoice.
A leaking tank right now
Shut off the cold water supply to the heater and turn the gas control to off or pilot. If the tank is electric, turn off its breaker. Then call the 24/7 line, and a plumber can tell you whether a new water heater installation is the next step.
If you smell gas, leave the building and call the gas utility or 911 first, before you call a plumber.
Permits and neighbors: the time questions specific to El Mirage
The city's published pages say permits are required for new construction and for repair, alteration or remodel work. They do not name water heaters one way or the other. Before you book, ask the El Mirage building department whether your swap needs a permit and an inspection. If it does, the wait for that step can add time on top of the install.
El Mirage adopted the 2018 International Plumbing Code and 2018 International Fuel Gas Code effective July 1, 2023. A plumber who works to those codes can plan the vent, gas connection and relief valve at the start, which avoids a second trip.
Peoria's city permit page says a water heater replacement needs a permit there. That is Peoria, not El Mirage, so do not assume the rule carries over. It does show that neighboring cities treat the same job differently.
Frequently asked questions
Usually yes, once the plumber confirms the unit has finished heating a full tank. Ask for the expected wait before the plumber leaves, since it depends on tank size and fuel.
Slightly, since it is heavier and takes longer to fill and heat. The bigger difference is in the vent and gas connection if the larger model needs different sizing.
Longer, in most cases. A tankless water heater needs venting, gas supply sizing and wall mounting that a tank does not. Ask the plumber for a time window that covers the whole conversion, not just the unit.
It can, but the city has not published a water heater rule that we can quote. Ask the El Mirage building department when you book, and ask your plumber to build any inspection into the schedule.
Question not answered here? Call (623) 301-9042
Sources and code notes
Code reference: El Mirage follows the 2018 International Plumbing Code (IPC) and the 2018 International Fuel Gas Code (IFGC). Ask the El Mirage building department which rules and permits apply to your job.