A licensed plumber installs the water heater: the water, gas and vent connections. A gas heater or a like-for-like electric swap on an existing circuit usually needs no electrician. A new dedicated circuit for an electric or heat pump unit is electrical work, so someone licensed for electrical work does that part.
Which Arizona license covers a water heater?
A plumbing license does, and it comes in three forms. The Arizona Registrar of Contractors (ROC) issues residential (R), commercial (C) and dual (CR) licenses for each trade. For a house, you want R-37 Plumbing or the dual CR-37.
The ROC's R-37 scope allows the licensee to install and repair water and gas piping systems, including "all fixtures, vents, and devices common to the industry." The dual CR-37 "allows the scopes of work permitted by the commercial C-37 Plumbing and the residential R-37R Plumbing licenses." The commercial C-37 covers plumbing done within property lines.
The classification text never uses the words "water heater." It lists what a heater is made of: water piping, gas piping, vents and fixtures. That is why a plumbing license is the one that fits.
Electrical work is its own trade. The ROC's C-11 Electrical classification allows the licensee to "install, alter, and repair any wiring, related electrical material and equipment used in the generating, transmitting, or utilization of electrical energy less than 600 volts." The residential version is R-11, and the dual version is CR-11. The ROC's general contractor classifications say the same thing from the other side: electrical and plumbing work must be subcontracted to appropriately licensed contractors.
Who does what, by type of heater?
The plumber does the water, gas and vent side on every type. The wiring side changes with the heater.
| Heater type | Plumber (R-37, CR-37) | Electrician (R-11, CR-11) |
|---|---|---|
| Gas tank | Water, gas line, sediment trap, vent, relief valve | Usually nobody. Check the manual for any outlet the model needs |
| Electric tank, same size and wiring | Water, relief valve, drain | Only if the existing circuit or breaker is wrong or damaged |
| Electric tank, new or upgraded circuit | Water, relief valve, drain | Dedicated circuit, breaker, disconnect |
| Heat pump (hybrid) | Water, condensate drain, relief valve | A dedicated 208/240-volt circuit if none exists. See hybrid water heaters |
| Gas tankless | Gas sizing, water, vent through a wall or roof | A 120-volt outlet near the unit, if none exists |
| Electric tankless | Water, relief valve | The model's manual sets the circuit it needs |
Before you accept a "no electrician needed," ask for the model number. Manuals set the electrical requirements, and they vary by model.
What do the manufacturers say?
They say to hire qualified people, and they name the electrical part specifically.
Rheem's electric tank manual says: "A separate branch circuit with copper conductors, overcurrent protective device and suitable disconnecting means must be provided by a qualified electrician." Rheem's heat pump guide says: "If your installation involves setting up a new 240V electrical circuit, this work must be handled by a licensed electrician."
The gas side is written the same way. Rheem's gas manual says: "Installation and service must be performed by a qualified installer, service agency or the gas supplier." Rinnai's tankless manual says: "A trained and qualified professional must install the appliance, inspect it, and leak test the water heater before use." It adds that the warranty may be voided by improper installation.
Can a plumber do the wiring too?
Ask them. The R-37 scope text is about water and gas piping, fixtures, vents and devices. It does not mention wiring, and the wiring scope sits in the electrical classifications. So a plumbing company can hold the license for the water and gas, and bring in a licensed electrical contractor for a new circuit, or hold both.
You do not need to work out the licensing yourself. Ask one question: who is doing the electrical, and what is their ROC license number? A straight answer is either that the company holds that license or that its licensed electrician does the work. Either is fine. A vague answer is not.
Can I install my own water heater in Arizona?
Sometimes, if the house is yours. A.R.S. 32-1121 exempts owners who improve their own property and do the work themselves. The statute limits that to structures "intended for occupancy solely by the owner" that are "not intended for sale or for rent." Proof that the owner sold, rented or offered the structure for sale or rent within a year of completion is prima facie evidence that the project was done for that purpose.
The exemption removes the license requirement. It does not remove code, permit or safety rules. A gas water heater does not forgive a bad vent. For the full picture, read can I do my own plumbing in Arizona, and gas line work and who can do it if gas is involved. Skip the DIY on any job you would have to test for gas leaks yourself.
Does the job need a permit?
Often it does not, when a licensed contractor swaps a heater in kind. A homeowner install, a fuel change or a move to tankless usually does. The details are in do I need a permit to replace a water heater in Phoenix. The ROC also says a license is generally required when a permit is required, whatever the price. That is one more reason to hire the right license.
How do I check the license?
Use the ROC contractor search at roc.az.gov. Look up the license number or business name. Confirm that the license is active and that the classification is plumbing or electrical, as the job needs. The step-by-step version is in how to verify a plumber's ROC license.
What should I ask before hiring?
- What is your ROC license number, and which classification is it?
- Who does the electrical work, and what is their license number?
- Does the written price include the relief valve and the pipe connections? Do you haul away the old heater?
- Will you pull a permit if one is required, and who books the inspection?
- What is covered by the workmanship warranty?
The rest of the interview is in questions to ask before hiring a plumber and how to choose a plumber. The relief valve and venting rules that the installer works to are covered in UPC 507, water heater installation and UPC 510, water heater venting.
HQ is licensed and insured, and gives free estimates and upfront pricing before work starts.
What is the short version?
- 1Plumber for the water, gas and vent side, every time.
- 2Electrician only when a new circuit, breaker or disconnect is needed.
- 3Confirm both licenses on the ROC search before work starts.
- 4Get the permit answer in writing.