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SetbackIQ

Homeowner rules in Montgomery County, MD

A person last checked these rules on October 20, 2026. This is guidance only, so confirm with Montgomery County before you build.

Disclaimer: This is general information, not legal or professional advice for any one property. Codes change. SetbackIQ is not a zoning determination, a permit, or a survey, and it does not replace an architect, engineer, or lawyer. Confirm with your building and zoning offices before you build, buy, or sign a contract.

Permits and building

  • Do I need a permit?Montgomery County permits every shed and every new fence. No permit is needed for patios, walkways, driveways on the lot, play equipment and treehouses, prefabricated pools under 18 in deep, or retaining walls up to 48 in with no surcharge.
  • Solar panelsZoning height limits don't apply to solar panels, and panels may project up to 3 ft into a side setback. Solar needs DPS electrical and building permits. Maryland law limits HOA bans.
  • AC units, heat pumps and generatorsAC units, heat pumps and generators may project up to 5 ft into a front or rear setback. Even replacing heating equipment needs a permit. Noise at the property line: 65 dBA by day, 55 dBA at night.
  • EV charging at homeA Level 2 charger or new circuit needs a DPS electrical permit.
  • Construction hours and noiseConstruction noise may not exceed 75 dBA unless a noise suppression plan allows more. General limits are 65 dBA by day and 55 at night.
  • Energy codes, green building and upkeepNew houses and additions follow the county's adopted building and energy codes. Upkeep of existing homes is enforced under County Code Chapter 26, Housing and Building Maintenance Standards.

Yard and structures

  • Fences and wallsEvery new fence needs a DPS permit. Fences up to 6.5 ft (8 ft next to commercial or industrial zones) are exempt from setbacks, and height is measured from the lowest grade under the fence.
  • Retaining wallsA retaining wall up to 48 in, measured from the bottom of the footing, needs no permit unless it supports a surcharge. Retaining walls made necessary by street changes are exempt from setbacks.
  • Corner sight trianglesOn a corner lot in a residential zone, nothing over 3 ft above curb level within 15 ft of where the front and side street lines meet.
  • Decks, porches and roof decksEvery deck needs a DPS permit, built to the county's deck guidelines. Unenclosed porches and decks may project into setbacks only as far as § 59-4.1.7 allows.
  • Sheds and garagesEvery shed needs a permit in Montgomery County, whatever its size. Accessory buildings stay behind the house and meet the zone's accessory setbacks.
  • Pools and hot tubsPools and hot tubs need a DPS permit unless the pool is prefabricated and under 18 in deep. A pool is an accessory structure and follows the zone's accessory setbacks.
  • Exterior lighting and light trespassOn-site lighting must measure 0.5 footcandles or less at the lot line, with full or partial cutoff fixtures.
  • Driveways and front-yard parkingAny vehicle or trailer parked in front of the house must be on a surfaced area, capped at 30% of the area or 320 sq ft in R-200 and R-90 and 35% or 320 sq ft in R-60 and R-40. The driveway apron in the right-of-way needs a permit.
  • Pergolas, play sets and carportsPlay equipment, playhouses and treehouses need no permit. Pergolas, gazebos and carports are accessory structures and need one.

Land and environment

  • TreesNo permit is needed to remove a tree on an existing house lot by itself. Once your project needs a sediment control permit, the Tree Canopy Law (Ch. 55) applies and requires shade tree planting or a fee. Larger development falls under Forest Conservation (Ch. 22A) instead. Trees in the right-of-way need a Roadside Tree permit.
  • Floodplains, RPAs, wetlands and stormwaterWork in a mapped floodplain needs a floodplain district permit (County Code Ch. 19, Art. III). Stream valley buffers and wetlands are reviewed with sediment control permits. Montgomery has no Virginia-style RPA and no tidal Critical Area.
  • Steep slopes and problem soilsMontgomery has no steep-slope permit for an ordinary house lot. Slopes of 25% or more (15% in Ten Mile Creek and in Special Protection Areas next to wetlands) count as steep in Planning's Environmental Guidelines, which apply when a development plan is reviewed: stream buffers grow to take in the whole slope, and septic fields are banned on slopes over 25%. For a building permit, steep ground mainly shows up through the sediment control permit and engineered foundation and wall designs.
  • Historic districtsOn a Master Plan historic site or in a historic district, exterior changes need a Historic Area Work Permit from the Historic Preservation Commission. SetbackIQ checks the county's historic preservation map.
  • Grading, easements and demolitionLand disturbance over 5,000 sq ft or 100 cubic yards needs a sediment control permit. Demolition needs a DPS permit and, on historic property, a HAWP.

Living and use

  • RVs, boats and trailers at homeOn a lot up to half an acre, you may park one light commercial vehicle and one unoccupied recreational vehicle. Larger lots allow more. Lots over 2 acres have no limit.
  • Chickens, bees and urban farmingHens are allowed under the urban farming standards: one bird per 1,000 sq ft of lot, no roosters, on a farm area of at least 2,500 sq ft, with coops 15 ft from every lot line and no taller than 14 ft. Bees are allowed without the minimum area.
  • Home businessesThree tiers: no-impact (5 visits a week, no in-person sales) needs registration. Low-impact (1 non-resident employee, 20 visits a week, a third of eligible space up to 1,500 sq ft). Major-impact (2 non-resident employees, 35 visits a week, 8 a day) needs conditional use approval.
  • Family child care homesFamily day care for up to 12 people is a permitted use. The provider must live there and no more than 3 non-resident staff may be on site. The Maryland State Department of Education registers family child care homes.
  • Occupancy limitsA household is any number of related people, up to 5 unrelated people, or 2 unrelated adults with their relatives. An ADU may house no more than 2 adults.
  • Short-term rentalsYou need a DHCA license ($500 a year) and must rent your primary residence. With you away, the cap is 120 nights a year. With you present, no cap. No more than six adult guests.