Garrett County ADU Rules 2026: No Countywide Zoning, Deep Creek Rules & HB 1466 Transition

Garrett County is unlike every other Maryland county because it does not have countywide zoning. County zoning applies within the Deep Creek Watershed, while several incorporated towns maintain their own zoning systems. Outside those zoned areas, a zoning permit generally is not required, but building permits, septic/well approvals, floodplain review and other development rules can still control an ADU project.

The first question for a Garrett County homeowner is therefore not simply “How large can my ADU be?” It is which land-use system controls this parcel? A property in the Deep Creek Watershed, Oakland, Accident or another zoned town may face a zoning ordinance that does not apply to an otherwise similar property elsewhere in unincorporated Garrett County.

Last verified: September 13, 2026. We found no countywide Garrett County ADU ordinance enacted for HB 1466 implementation in the official materials reviewed. This page distinguishes zoning jurisdiction from building, septic, floodplain and other permitting requirements.

Garrett County ADU status at a glance

Where zoning applies in Garrett County

Garrett County’s Planning & Land Management Division states that the County has no countywide zoning. Zoning exists within the Deep Creek Watershed and within the municipal boundaries of six towns: Accident, Friendsville, Grantsville, Loch Lynn Heights, Mountain Lake Park and Oakland.

That makes jurisdiction identification unusually important. Two nearby properties can have very different approval paths depending on whether one lies inside the Deep Creek Watershed, inside a zoned town, or in an unzoned unincorporated area.

What applies in the Deep Creek Watershed?

The Deep Creek Watershed is governed by Chapter 157, the Deep Creek Watershed Zoning Ordinance. Most new structures or changes in land/building use in the watershed require a zoning permit, and some projects may require a variance or special exception.

The ordinance contains some older references to “accessory dwelling units,” including a special provision for certain nonresidential structures on lakefront Town Center lots, but that is not a general residential ADU standard for ordinary single-family properties. Homeowners should therefore ask Planning & Land Management to identify the provision that currently controls a proposed residential ADU in the watershed.

Deep Creek properties may also face lakefront, buffer, stormwater, floodplain and other site-specific constraints in addition to zoning.

What if the property is outside a zoned area?

Garrett County says that outside the Deep Creek Watershed and the six zoned towns, no zoning permit is generally required. That does not mean “no rules apply.” A residential ADU can still require building permits, approved plans, sewage-disposal and water-supply review, floodplain review, grading or stormwater approval, addressing, and compliance with applicable building and health codes.

This distinction matters because HB 1466 is a land-use law. In Garrett County, the practical implementation question is how the state’s ADU mandate will interact with areas where the County historically has not regulated land use through zoning.

Why HB 1466 creates a special Garrett County question

Maryland HB 1466 requires counties and municipalities with planning and zoning authority to adopt a local law authorizing ADUs on land with an existing single-family detached dwelling by October 1, 2026. The state defines an ADU as a secondary unit on the same property as a primary single-family detached dwelling and permits a size up to 75% of the primary dwelling.

The state also says local ADU laws may not impose side or rear setbacks greater than those used for accessory structures, and additional ADU parking requirements require a parking study plus a waiver process.

Building permits, septic, well and floodplain review

Garrett County’s Permits & Inspections Division processes residential building permits and coordinates review by other agencies. County development guidance says a permit is required for sewage-disposal and water-supply systems before constructing a building for human occupancy or use, and additions or alterations can require Environmental Health review.

For properties on private septic or well systems, capacity and siting should be checked before final ADU plans are prepared. Residential development plans can also need grading review, and development within mapped floodplains requires separate approval.

Use our Maryland ADU Septic & Well Guide as an early feasibility screen, but confirm the parcel-specific requirements with Garrett County and the Garrett County Health Department.

Town rules can replace the County zoning path

Accident, Friendsville, Grantsville, Loch Lynn Heights, Mountain Lake Park and Oakland have their own zoning systems. Garrett County staff assists with administration in several of these jurisdictions, but the applicable ordinance is the town’s ordinance—not the Deep Creek Watershed ordinance.

The County also notes that municipalities assign their own property addresses. If a parcel is inside town limits, verify zoning and addressing with the municipality before relying on a County-level summary.

What Garrett County homeowners should do now

1. Check whether the parcel is zoned. Use the County zoning map to determine whether the property is inside the Deep Creek Watershed or an incorporated town.
2. Identify the correct ordinance. Do not apply Deep Creek rules to an unzoned rural parcel or town rules to property outside that municipality.
3. Ask for the current ADU pathway in writing. Because a countywide HB 1466 implementation ordinance was not verified, ask Planning & Land Management which rule currently controls the proposed ADU.
4. Check septic/well capacity early. Private-system feasibility can determine whether the project can proceed.
5. Check floodplain, grading and stormwater constraints. These can apply even where zoning does not.
6. Do not confuse a short-term rental with an ADU. Garrett separately regulates transient vacation rental units, especially around Deep Creek.
7. Re-check after October 1, 2026. Watch for a County or municipal implementation law responding to HB 1466.

Primary sources used for this Garrett County guide

• Garrett County — Zoning
• Garrett County — Deep Creek Watershed Zoning
• Garrett County — Deep Creek Watershed Zoning Ordinance
• Garrett County — Permits & Inspections
• Garrett County — Development and Construction Guide
• Maryland Department of Planning — HB 1466 ADU FAQ

For statewide comparison, use the Maryland County ADU Rules Tracker. Maryland ADU Guide is maintained by Gijo John as an independent research publication. Verify property-specific requirements with the controlling local agency before relying on this page for design or construction decisions.