Do you need a permit for an AC unit, heat pump, or generator in Prince George's County, MD?
It depends on the details of your project.
DPIE requires a mechanical permit to install or replace a furnace, heat pump or air-conditioning unit, including a like-for-like swap.
Mechanical permits are applied for online by a licensed master HVACR contractor.
Gas work, including gas appliance replacement, must be done by a WSSC Water-licensed gasfitter.
A person last checked these rules on October 20, 2026. This is guidance only, so confirm with Prince George's County before you build.
Check your exact lot
Your zoning district sets the setbacks, and a flood zone can change the permit answer. Enter your address to see both.
Permits a AC unit, heat pump, or generator can need in Prince George's County
| Permit | When it applies |
|---|---|
| Mechanical permit | DPIE requires a mechanical permit to install, alter, repair or replace heat pumps, air-conditioning units and furnaces, so even a like-for-like swap needs one. |
| Electrical permit | DPIE requires an electrical permit to install, relocate or repair any device that uses electricity, which covers a generator's transfer switch and an outdoor unit's circuit and disconnect. SetbackIQ reads this to include reconnecting a replacement unit; ask DPIE if your contractor says the mechanical permit covers it.Medium confidence |
| Gas permit (WSSC Water) | In Prince George's County, gas piping and gas appliance work goes through WSSC Water and must be done by a WSSC-licensed gasfitter.Medium confidence |
| Historic Area Work Permit (HPC) | Exterior work on a designated historic site, in its environmental setting or in a county historic district needs a Historic Area Work Permit from the Historic Preservation Commission. |
Limits that apply citywide
| Front and corner side yards | A detached outdoor unit or generator pad is an accessory structure, so it can't sit in the required front yard or a corner lot's street side yardMedium confidence |
|---|---|
| Side and rear yards | Allowed in the required side or rear yard with no minimum distance from the line (units over 10 ft tall step back 1 ft per foot)Medium confidence |
| Easements | Not in a platted or recorded easement or over a known utilityMedium confidence |
Local details
- Prince George's Zoning Ordinance has no rule written for air conditioners, heat pumps or generators. SetbackIQ applies the general accessory-structure rules (Section 27-5202): keep units out of the front yard and a corner lot's street side yard. Many towns and HOAs add their own limits.
- Call 811 at least a few days before you dig footings or post holes. Utility locating is free.
- HOA covenants and deed restrictions can be stricter than city rules. Check yours before you build.
- Prince George's renamed its zones in 2022. If a plat or listing says R-55 or R-80, the lot is now RSF-65 or RSF-95.
How to apply
Common questions
- When does an AC unit, heat pump, or generator need a mechanical permit in Prince George's County?
- DPIE requires a mechanical permit to install, alter, repair or replace heat pumps, air-conditioning units and furnaces, so even a like-for-like swap needs one. A standby generator isn't heating or cooling equipment. It is permitted under electrical (and gas, if fueled).
- Where do I apply for an AC unit, heat pump, or generator permit in Prince George's County?
- Apply through DPIE Momentum permitting portal, or call (301) 636-2050.
Sources
- Prince George's County DPIE, When is a Mechanical Permit Required?. Checked 2026-10-22
A mechanical permit is required to erect, install, enlarge, alter, repair, remove, convert, or replace a mechanical heating, ventilating, or air-conditioning system, the installation of which is regulated by the International Mechanical Code (IMC), Internat…
- Prince George's County DPIE, Mechanical Permits. Checked 2026-10-22
To obtain permission to apply for Mechanical Permits online, the Licensed/Master HVACR will need to register.
- Prince George's County DPIE, When is an Electrical Permit required?. Checked 2026-10-22
An electrical permit is required for work that involves installation, relocation, repairing, or maintaining any wiring or device designed for conducting, consuming or converting electrical current.
- WSSC Water, Information for homeowners (plumbing and gasfitting permits). Checked 2026-10-22
WSSC Water Plumbing and Gasfitting Regulations require that in Montgomery and Prince George's counties, most plumbing projects must be done by a WSSC Water-licensed plumber or gasfitter... [including] all gas work such as furnace, gas water heater and gas a…
- Prince George's Planning, Historic Area Work Permits. Checked 2026-10-21
[In Prince George's County, properties] designated as a historic site, or those within a locally designated historic district, may require a HAWP... Here are examples of projects that always require a HAWP: Replacement, alteration, or the addition of roofs,…
- Prince George's County Zoning Ordinance §§ 27-5202(c) and 27-2203, and Part 27-2 definitions (enCodePlus). Checked 2026-10-22
[27-5202(c)] (1) Except as otherwise expressly allowed in this Ordinance, an accessory use or structure shall not be located within any platted or recorded easement or over any known utility... (4) Unless otherwise provided in Section 27-5203, Standards Spe…