Do you need a permit to replace a water heater, furnace or AC?

What state rules say about permits for swapping a water heater, furnace or air conditioner, in the states we've confirmed from official sources, and what a permit costs.

Updated September 28, 2026

Your local building department can tell you whether your job needs a permit. State rules set the starting point: some require a permit to replace equipment, some exempt certain swaps, and some leave it to cities and counties. The table below says what we've confirmed for each state, and it's a place to start, not the final word.

Before you start

Call your city or county building department, or check its website, and ask:

Whether replacing this water heater, furnace or air conditioner with a similar one needs a permit.
Who can apply: you, or only a licensed contractor.
What the fee is, and whether an inspection follows.
What to do if the replacement is an emergency and can't wait for a permit.

Where a state rule requires a permit, ask who issues it.

What state rules say

State	What the state rule says
Alabama	No statewide plumbing or mechanical code covers private buildings. The state codes cover state-owned buildings, schools and hotels, so the local building department sets permit rules¹
Alaska	The state fire marshal's plan review and permit exempts housing of three units or fewer, and cities such as Anchorage, Fairbanks and Juneau run their own programs. A home's equipment permit is a local matter²
Colorado	Water heaters and other plumbing: the Colorado Plumbing Code adopts the International Plumbing Code's permit section.³ For heating and cooling work, ask your local building department
Delaware	The state plumbing code requires plumbing permits, but no permit or fee is needed from the Division of Public Health to replace existing equipment, and water heaters are named. Moving equipment or adding new equipment needs a permit.⁴ For heating and cooling work, ask your local building department
Georgia	The state's amendments take the administration chapter out of the Georgia plumbing and mechanical codes and leave it as a guide for local governments to write their own procedures, so permit rules are local^{5, 6}
Hawaii	The State Building Code Council adopts the codes, and each county adopts them with its own amendments and runs permitting, so the county sets permit rules⁷
Indiana	The state says one- and two-family homes fall under the local government's jurisdiction, and where there isn't one, residential matters are a private civil issue⁸
Minnesota	The state building code requires a permit to install or replace any gas, mechanical or plumbing system. Portable appliances and parts that don't change the equipment's approval are exempt, and an emergency replacement can go ahead with the application due the next business day⁹
Montana	Plumbing: where the state has jurisdiction, anyone in the business of installing, altering or repairing plumbing needs a state plumbing permit. Homeowners working on their own home are exempt, and certified cities and counties run their own programs. Heating and cooling: state law exempts homes of fewer than five units from state mechanical permits, so only a local program would require one^{10, 11}
Nebraska	A city or village without its own plumbing ordinance falls back on a default plumbing code, but that default leaves out single-family homes, so permit rules are local¹²
Nevada	No statewide plumbing or mechanical code covers private buildings, so the local building department sets permit rules¹³
New Mexico	Plumbing and mechanical work can't be installed, repaired or altered without a permit from the authority having jurisdiction. An emergency equipment replacement can start with the application due the next working day¹⁴
Pennsylvania	The Uniform Construction Code lists replacing mechanical or plumbing systems as permit work. It doesn't apply to repairs of a home, or to alterations of a home without structural or exit changes, unless a local ordinance says so. For a house, it's up to the municipality^{15, 16}
South Dakota	Plumbing: the state plumbing commission requires a plumbing installation certificate (its name for a permit) and a state inspection for all plumbing installations, except in cities that do their own inspections (Aberdeen, Brandon, Rapid City, Sioux Falls and Spearfish). Water heaters aren't named.¹⁷ For heating and cooling work, ask your local building department
Virginia	The Uniform Statewide Building Code requires a permit for mechanical systems and equipment, and an emergency replacement can be filed for by the next working day. In a house, replacing a mechanical appliance that doesn't burn gas or oil is exempt, and so is replacing a plumbing fixture without changing the system¹⁸
Wisconsin	The Uniform Dwelling Code doesn't apply to repairs of plumbing, heating or air conditioning systems, or to alterations of homes begun before the code took effect, though a municipality may adopt it for those. Permits for replacements are local¹⁹

States that aren't in the table

A state isn't in the table if we haven't settled its rule, if our finding was low confidence, or if we couldn't confirm it on an official page. That's every other state and DC, including Louisiana, North Dakota, Tennessee, Vermont and Washington, where the research is still open. It doesn't mean those states have no permit rule. Ask your local building department.

What a permit costs

Fees are set locally. Three city fee schedules show the scale for a heating or cooling equipment swap:

Winston-Salem, North Carolina charges a flat $100 for a residential mechanical changeout permit, electrical included.²⁰
Spring Lake Park, Minnesota charges $50 per unit for a mechanical permit, with a $100 minimum.²¹
San Diego charges $176.57 for the first furnace, air handler, mini-split or packaged heat pump, and $131.52 for an air conditioning condensing unit.²²

For a water heater, Winston-Salem charges a flat $100 for a changeout permit, electrical included,²⁰ and San Diego charges $122.97.²²

Ask each contractor who applies for the permit and whether the fee is in the quote. The water heater guide, the air conditioner guide and the heat pump or furnace guide cover what the equipment costs.

Rules from state legislatures, agencies and code bodies; fees from city fee schedules, checked September 2026.

Do you need a permit to replace a water heater, furnace or AC?

Before you start

What state rules say

States that aren't in the table

What a permit costs

Sources (22)

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