Maryland · Penalties if you skip one
What you can build without a permit in Maryland
By Mario Bailey Last checked · 55 official sources
Quick answer
Across the 4 Maryland jurisdictions we have verified, 3 of 45 project rules need no permit at all, 24 turn on a size or scope condition the jurisdiction publishes, and 18 require a permit regardless. Roof replacement work is where the answer most often comes with a published condition rather than a flat yes: 4 of the 4 jurisdictions that answer publish one. The numbers are not statewide: fence thresholds alone run from 4 to 7 feet depending on the jurisdiction.
How to read this page
"No permit" means the jurisdiction publishes that the work needs no building permit. "Depends" means it publishes a size, height, depth, cost or scope condition that decides the answer, quoted in its own words in the last column; the number beside it is the figure that condition turns on, and which side of the number is exempt is stated by the condition, not by us. Exempt from a building permit is not exempt from zoning, setbacks, height limits, flood rules, an HOA, or a separate electrical, plumbing or mechanical permit, and several of the conditions below say exactly that.
Roof Replacement
Montgomery County requires no roof replacement permit at all. 3 of 4 make the roof replacement answer turn on a size or scope condition the jurisdiction publishes.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Montgomery County | No permit | Re-roofing limited to replacement of the covering material (shingles, tiles, etc.) does not require a building permit in Montgomery County. | |
| Baltimore County | Depends | 50 percent | share of the sheathing or deck being replaced in a roofing job. |
| Howard County | Depends | 64 sq ft | roof covering replacement with no other structural repairs is exempt, including up to 64 sq ft of roof sheathing; replacing more sheathing or any other structural repair requires a building permit. |
| Prince George's County | Depends | Replacing roof shingles alone, with no structural repair involved, needs no permit in Prince George's County, which is DPIE's most frequently asked roofing question and is answered the same way in three separate county publications. |
Fence
3 of 4 make the fence answer turn on a size or scope condition the jurisdiction publishes, and the 2 that state a number publish figures from 4 to 7 feet. Montgomery County requires a permit for fence work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Baltimore County | Depends | 42 inches | fence height measured vertical to ground, including a fence set on top of a wall. |
| Howard County | Depends | 7 feet | fences 7 ft or under, not enclosing a pool, are exempt from a building permit; over 7 ft or enclosing a pool requires a Miscellaneous Structures building permit. |
| Prince George's County | Depends | 4 feet | fence height above grade, with a permit required at any height on a corner lot, in a historic or protected area, or in the 100-year floodplain. |
| Montgomery County | Permit required | A permit is required to install any fence in Montgomery County. |
HVAC
3 of 4 make the HVAC answer turn on a size or scope condition the jurisdiction publishes. Montgomery County requires a permit for HVAC work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Baltimore County | Depends | Baltimore County issues a mechanical permit rather than an HVAC permit, and requires one in defined circumstances rather than for every job: new ductwork in a dwelling that has none, added ductwork not covered by another permit, mechanical work left out of an existing building permit's scope, and additional mechanical work. | |
| Howard County | Depends | Howard County's HVAC Permit Policy requires a permit for all HVAC installations in new residential construction, conversions to a different fuel or energy source, additions or alterations requiring new or altered HVAC systems (including duct extensions for additions, finished basements, or alterations, effective January 25, 2021), and equipment replacement with a change of fuel or power source. | |
| Prince George's County | Depends | Permanently installed heating and cooling equipment requires a Mechanical Permit in Prince George's County, and the same jobs usually require an Electrical Permit as well, while gas-fired equipment adds a WSSC gasfitting permit. | |
| Montgomery County | Permit required | A mechanical permit is required in Montgomery County for any work involving heating, ventilating, and air-conditioning systems including installation, replacement, repair, or conversion. |
Shed
3 of 4 make the shed answer turn on a size or scope condition the jurisdiction publishes, and the 3 that state a number publish figures from 120 to 200 sq ft. Montgomery County requires a permit for shed work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Baltimore County | Depends | 120 sq ft | accessory structure floor area. |
| Howard County | Depends | 200 sq ft | sheds under 200 sq ft (one-story, non-conditioned, detached) are exempt from a building permit; 200 sq ft or more requires a Miscellaneous Structures building permit. |
| Prince George's County | Depends | 150 sq ft | floor space of a one-story detached accessory structure, and only one such exempt structure is allowed per property. |
| Montgomery County | Permit required | A building permit is required to install, move, or construct any shed in Montgomery County regardless of size. |
Patio
Howard County and Montgomery County require no patio permit at all. 1 of 3 makes the patio answer turn on a size or scope condition the jurisdiction publishes. 1 publishes no answer we could verify.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Howard County | No permit | Howard County's local amendment to IRC Section 105.2 (Work Exempt from Permit), enacted by Council Bill 71-2021 and re-enacted with the same language by Council Bill 24-2025 (2024 IRC adoption, effective September 7, 2025), lists 'installation of patios, sidewalks, or landscaping' as exempt site work for existing single-family dwellings. | |
| Montgomery County | No permit | Ground-level patios made of concrete or pavers do not require a building permit in Montgomery County. | |
| Prince George's County | Depends | 500 sq ft | area of an at-grade patio, with a permit required at any size if stairs or ramps are built due to elevation change. |
Pool
2 of 4 make the pool answer turn on a size or scope condition the jurisdiction publishes. Howard County and Montgomery County require a permit for pool work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Baltimore County | Depends | 250 sq ft | above-ground pool surface area, where the water depth is 24 inches or more; in-ground pools require a permit at any size. |
| Prince George's County | Depends | 24 inches | prefabricated pools accessory to one- and two-family dwellings that are installed entirely above ground, hold no more than 5,000 gallons, and have a four-foot fence around the pool perimeter. |
| Howard County | Permit required | Howard County requires a building permit application for both above-ground pools (plot/site plan, manufacturer installation guidelines, and a compliance certificate at inspection) and in-ground pools (plot/site plan, Howard County ISPSC Chapter 8 checklist, and a compliance certificate), effective September 7, 2025. | |
| Montgomery County | Permit required | A building permit and an electrical permit are both required for any residential swimming pool construction, alteration, or enlargement in Montgomery County. |
Bathroom Remodel
All 2 make the bathroom remodel answer turn on a size or scope condition the jurisdiction publishes.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Howard County | Depends | Set locally. | |
| Montgomery County | Depends | Set locally. |
EV Charger
All 2 make the EV Charger answer turn on a size or scope condition the jurisdiction publishes.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Howard County | Depends | Permit requirements are set by the county, but the work is regulated statewide: every electrical installation in Maryland must conform to the National Electrical Code or the county's adopted electrical code, and state law makes it unlawful to provide electrical services without any permit a local jurisdiction requires. | |
| Montgomery County | Depends | Permit requirements are set by the county, but the work is regulated statewide: every electrical installation in Maryland must conform to the National Electrical Code or the county's adopted electrical code, and state law makes it unlawful to provide electrical services without any permit a local jurisdiction requires. |
Water Heater
All 2 make the water heater answer turn on a size or scope condition the jurisdiction publishes.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Howard County | Depends | It depends on the county. | |
| Montgomery County | Depends | It depends on the county. |
Deck
1 of 4 makes the deck answer turn on a size or scope condition the jurisdiction publishes. Howard County, Montgomery County and Prince George's County require a permit for deck work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Baltimore County | Depends | 120 sq ft | deck floor area, with a permit also required for any deck more than 16 inches above the lowest grade. |
| Howard County | Permit required | Howard County DILP requires a building permit with construction plans for decks and screened porches of all sizes, regardless of height, effective September 1, 2022 (Residential Accessory Structure Memo). | |
| Montgomery County | Permit required | A building permit is required for all decks supported by footings in Montgomery County regardless of height above grade. | |
| Prince George's County | Permit required | Prince George's County publishes a flat requirement: building or replacing a porch or deck takes a building permit and plans, with no size or height exemption anywhere in DPIE's published exemption list. |
Electrical
1 of 4 makes the electrical answer turn on a size or scope condition the jurisdiction publishes. Howard County, Montgomery County and Prince George's County require a permit for electrical work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Baltimore County | Depends | Baltimore County requires an electrical permit for essentially all electrical work, including circuit extensions, low voltage wiring, and connecting replacement equipment to existing wiring. | |
| Howard County | Permit required | Howard County DILP requires an electrical permit for residential electrical work. | |
| Montgomery County | Permit required | An electrical permit is required in Montgomery County for all new electrical work, new circuits, fixture installations, and service upgrades. | |
| Prince George's County | Permit required | Electrical work on an existing Prince George's County dwelling requires an Electrical Permit, and the application must come from a Master Electrician licensed by the State of Maryland, so a homeowner cannot pull this permit themselves. |
Plumbing
1 of 4 makes the plumbing answer turn on a size or scope condition the jurisdiction publishes. Baltimore County, Howard County and Montgomery County require a permit for plumbing work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Prince George's County | Depends | This is a jurisdictional handoff, and it is the answer: DPIE does not review plumbing plans or issue any plumbing permits at all, and every plumbing permit in Prince George's County is issued by the Washington Suburban Sanitary Commission, which keeps a satellite office inside DPIE at 9400 Peppercorn Place, Suite 650. | |
| Baltimore County | Permit required | Baltimore County requires a permit for all plumbing and gasfitting work, with no size or cost threshold. | |
| Howard County | Permit required | Howard County DILP requires a plumbing permit for residential plumbing work. | |
| Montgomery County | Permit required | Plumbing permits in Montgomery County are handled by the Washington Suburban Sanitary Commission (WSSC) rather than the county DPS for work involving the water and sewer system. |
If the work is already built
In Maryland, penalties for building without a permit are set by each county and municipality, not by state building law. The Maryland Building Performance Standards adopt the IBC statewide, but the subtitle contains no fine, misdemeanor, or stop-work provision for unpermitted work.
Maryland penalties, the after-the-fact path, and what the statute actually says
1 of the 46 rules we hold for Maryland are unresolved because the jurisdiction publishes no answer; they are counted nowhere above. The 45 answered rules come from 55 official sources, each linked from the permit page behind every jurisdiction name. See the full picture for the state on the Maryland permit requirements page, or the national view of which projects need a permit at all on Do you need a building permit?
This page compiles what each Maryland jurisdiction publishes, with a last checked date. It is not legal advice, and a project that is exempt from a building permit can still need zoning approval or a trade permit. Confirm with the office linked from the jurisdiction's page before you build.