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Installing a water heater means shutting off water and fuel, draining the old tank, disconnecting the supply lines and the vent or wiring, setting the new unit level, reconnecting with new flex lines, filling before you switch the power on, then checking for leaks. Electric swaps are within reach for a confident DIYer. Gas is not. Our water heater repair and replacement team covers the Triad.
Key Takeaways
- Fill the tank before restoring power. Energising a dry electric element destroys it in seconds.
- North Carolina requires a permit for a water heater replacement, and the work gets inspected.
- Gas work is not a DIY job. Venting and combustion air are life-safety items, not preferences.
- Budget half a day for a straight electric swap, longer if anything has to be re-piped.
- Old tanks weigh far more than you expect once full of sediment. Do not lift one alone.
Be Honest About Which Job This Is
There is a wide gap between swapping a like-for-like electric tank in a garage and anything involving gas, and the gap is mostly about what happens when it goes wrong.
| Job | Realistic for a DIYer? | Why |
|---|---|---|
| Electric, same size, same spot | Yes, with care | Water and a 240V circuit, no combustion |
| Gas, same size, same spot | No | Gas connection and flue venting |
| Changing tank size | No | Re-piping, sometimes circuit changes |
| Electric to gas or gas to electric | No | New fuel supply, new venting |
| Tank to tankless | No | Gas sizing, vent, condensate, power |
A gas water heater that vents badly puts carbon monoxide into the house. That is the reason this is licensed work in North Carolina, and the reason we will not walk anyone through it over the phone.
What You Need for an Electric Replacement
- Garden hose, bucket and towels
- Pipe wrench and adjustable wrenches
- Screwdrivers and a voltage tester
- Two new flexible water connectors
- New temperature and pressure relief valve and discharge pipe
- Teflon tape or pipe dope
- A drain pan if the unit sits above a finished space
- A hand truck and a second person
How to Install a Water Heater, Step by Step
- Pull the permit. Do this first. Your local inspections office issues it and the work gets signed off at the end.
- Kill the power. Switch the breaker off and confirm with a voltage tester at the unit. Do not trust the label on the panel.
- Close the cold water supply at the valve above the heater, then open a hot tap somewhere in the house to release pressure.
- Drain the tank. Hose onto the drain valve, run it outside or to a floor drain. Expect this to take a while and to smell.
- Disconnect the wiring. Remove the junction box cover, note which wire goes where, photograph it, then release the connectors and the ground.
- Disconnect the water lines at the unions or the flex connectors.
- Remove the old tank. Hand truck, two people, and a clear path. A drained tank still holds a surprising amount of sediment.
- Set the new unit. Level it, shim if needed, and leave clearance for the relief valve and the drain.
- Fit the new relief valve and run its discharge pipe down to within six inches of the floor. Never cap it, never reduce it.
- Connect the water lines with new flex connectors. Cold to the cold inlet, hot to the hot outlet. Getting these backwards is a common and annoying mistake.
- Fill the tank completely. Open the cold supply, leave a hot tap running upstairs, and wait until it flows steady with no air.
- Only now restore the power and set the thermostat to 120 degrees.
- Check everything for leaks after an hour, and again the next morning.
Step 11 is the one that ruins new heaters. An electric element fires dry and burns out within seconds, and that is not a warranty claim.
The Parts People Forget
These are the items that turn a Saturday job into a Sunday job, and they are the same ones every time.
- The permit. Skipping it causes problems at resale, and it can affect an insurance claim after a failure.
- An expansion tank. On a closed system with a check valve or a pressure reducing valve, thermal expansion has nowhere to go without one.
- A drain pan with a piped outlet whenever the unit sits above finished space.
- Disposal of the old tank. Most Triad transfer stations take them, but not on every day of the week.
- Seismic or earthquake strapping is not required here, but securing a tall tank in a garage against a car door is still sensible.
On energy use, the Department of Energy notes that water heating energy use is about 18% of a home’s total and usually its second largest energy expense, so the efficiency rating you pick matters more than the brand badge. Ratings for current models are listed on ENERGY STAR water heaters.
Water Heater Installation Questions
Can I install a water heater myself in North Carolina?
A homeowner can do plumbing work on their own primary residence in many cases, but the work still requires a permit and an inspection. Gas connections and venting are the practical limit, because the consequences of getting those wrong are carbon monoxide and fire rather than a leak.
How long does a water heater installation take?
A straight electric swap in an accessible spot runs about three to four hours including draining. Gas units take longer because of the vent connection. Anything involving re-piping, a new circuit or moving the unit becomes a full day.
Do I need an expansion tank?
If your home has a pressure reducing valve or a check valve on the incoming water, yes. That makes it a closed system, and heated water needs somewhere to expand. Without one, pressure spikes shorten the tank’s life and push the relief valve open.
What happens if I turn the power on before the tank is full?
The heating elements burn out almost immediately, because they are designed to be cooled by the water around them. You will have a brand new heater producing no hot water, and element failure from dry firing is not covered by warranty.
Is it cheaper to install a water heater yourself?
On paper, yes, because you save the labour. In practice you take on the permit, the disposal, the risk of a leak into finished space, and no labour warranty. For a straight electric swap that maths can work. For anything with gas in it, it rarely does.
Get It Installed With the Permit and the Warranty Intact
If you are replacing a water heater because the old one failed, you are also working against the clock with no hot water in the house. That is when mistakes happen.
Call All Star Plumbing at (336) 462-1080 and we will handle the permit, the install, the inspection and the removal of the old unit. A real person answers 24 hours a day, you get upfront pricing before work starts, and if we cannot fix it you do not pay. You can also book a water heater installation online.
Not sure what size to fit? Read our guide on what size water heater you need first. Considering going tankless at the same time, our tankless water heater service covers the whole conversion, and larger projects can go through our plumbing financing options.
Family owned in High Point since 2007, licensed, bonded and insured, and certified on AO Smith, Rheem, Bradford White, State, Navien and Rinnai.
All Star Plumbing
4003 North Main Street
High Point, NC 27265
Phone: (336) 462-1080
Hours: Open 24 hours, 7 days a week
NC Plumbing License #15130
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