Off-Grid Living in Montgomery County, Maryland

If you're picturing off-grid life in Montgomery County, Maryland, the first thing I want to correct is an assumption a lot of people bring from other rural Maryland counties: this county does NOT lack zoning. Montgomery County has a comprehensive, detailed countywide Zoning Ordinance (Chapter 59), run by the Montgomery County Planning Department (M-NCPPC) and enforced by the Department of Permitting Services (DPS). A big chunk of the county, roughly a third of its land, sits in the Agricultural Reserve, where density is intentionally limited (historically to around one house per 25 acres in the Rural Density Transfer Zone) to preserve farmland. That's a meaningful constraint if your off-grid dream involves buying raw acreage and just building something.

On dwellings: the county's clearest legal path to a small, independent living space is the Accessory Dwelling Unit (ADU) program. Since a 2018 zoning text amendment, ADUs (including detached "tiny houses") no longer need a special exception in most cases, but they do need to be licensed through the Department of Housing and Community Affairs (DHCA), inspected, and permitted through DPS. A few incorporated towns and cities in the county (Laytonsville, Barnesville, Garrett Park, North Chevy Chase, Rockville, Gaithersburg) are exempt from DHCA licensing and set their own local rules, so if you're eyeing land there, check with that municipality directly. I could not confirm that living full-time in an RV or tiny house on wheels as a permanent residence outside a licensed ADU or RV park is legal here, so don't assume it.

Building permits are required, issued by DPS, which also handles well and septic permitting on behalf of the Maryland Department of the Environment (MDE), an unusual delegation since most Maryland counties leave that to the local Health Department. Septic systems need a permit involving both a water-table test and a percolation test, and as of recent county practice, septic work tied to a building permit must be finished and approved before that building permit is issued. Composting toilets are addressed by the state: liquid discharge onto the ground needs an MDE discharge permit, while subsurface discharge approval typically runs through the local health authority.

Greywater reuse doesn't have a county-specific ordinance that I found; it falls back to Maryland's state framework, so confirm specifics with DPS or MDE. Rainwater harvesting, by contrast, is actively encouraged, the county's Department of Environmental Protection runs a RainScapes rebate program for rain barrels and cisterns, with minimum size thresholds for rebate eligibility.

Private wells are permitted and go through DPS's Onsite Systems Management Program, with water tested for bacteria and nitrates. Full grid disconnection as its own legal category isn't directly addressed anywhere I found; it's really an intersection of zoning, ADU licensing, and well/septic permitting, so treat it as unclear and confirm with the offices below before committing to a plan.