Off-grid site report

Montgomery County, MD

38.9825, -77.0967 · 328 ft elevation

Read this before you act on anything below. This is my researched starting point for Montgomery County, MD, not legal advice and not a guarantee. Rules change, and the deciding facts on any specific parcel (setbacks, perc results, overlay districts, deed restrictions, road frontage) live at the county or town office, not in any database. Before you buy land or build, confirm the current rules directly with the local zoning and health offices - the sources on this page tell you exactly who to call.

The local rulesMontgomery County, MD

Zoning & raw-land occupancy

RestrictedMontgomery County has a comprehensive countywide Zoning Ordinance (Chapter 59) administered by the Planning Department (M-NCPPC); the Agricultural Reserve covers about a third of the county with density limits. Raw-land off-grid occupancy outside an approved dwelling isn't addressed as its own category. source

Dwellings, tiny homes & RVs

RestrictedTiny houses are allowed as licensed Accessory Dwelling Units (ADUs) via DHCA licensing and DPS building permits, but full-time RV or tiny-house-on-wheels living as a permanent residence outside that framework is not confirmed as legal. source

Building permits & codes

RestrictedBuilding permits are required and issued by the Department of Permitting Services (DPS), which also handles well/septic permitting on the state's behalf, unlike most Maryland counties. source

Septic & composting toilets

RestrictedSeptic permits from DPS are mandatory, requiring water-table and percolation testing; composting toilet liquid discharge needs a separate Maryland Department of the Environment permit. source

Greywater reuse

Unclear - verifyNo Montgomery County-specific greywater ordinance was found; the state's Environment Article framework applies as the baseline, so confirm specifics with DPS or MDE. source

Rainwater harvesting

Generally allowedThe county's Department of Environmental Protection actively encourages rainwater harvesting through its RainScapes rebate program for rain barrels and cisterns, with minimum size standards for rebates. source

Private wells & water rights

Generally allowedPrivate wells are permitted through DPS's Onsite Systems Management Program, with required water table/percolation testing and lab analysis of water samples for bacteria and nitrates. source

Living disconnected from utilities

Unclear - verifyNo official source directly addresses full grid disconnection as its own legal category; it's governed indirectly through zoning, ADU licensing, and well/septic permitting, so treat this as unconfirmed and check with DPS and the Planning Department. source

Open the full county page with sources →

Sun30-year normals

Peak-sun hours, annual average: 4.8 hrs/day
Worst month (sizes an off-grid array): 3.5 hrs/day
Yearly output per 1 kW of panels: 1,380 kWh

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Weather1991-2020

Precipitation: 46 in/yr
Heating degree days: 4,398 (moderate)
Frost-free season: Apr 12 to Oct 29

How far help isstraight-line

Hospital: none within range
Fire station Bethesda-Chevy Chase Rescue Squad (Rescue Company 1): 0.6 mi
Hardware store Benjamin Moore: 1.6 mi
Grocery Magruder's: 1.6 mi

From OpenStreetMap. Road miles will be longer, often much longer in hill country.

Plan this spot

These open with this location's real numbers already filled in (ZIP 20824).

Size a solar system Heat loss & insulation Firewood per winter Rainwater harvest Garden size Panel tilt

Sources: US Census Bureau geocoder; NLR PVWatts v8 (solar); NOAA NCEI 1991-2020 climate normals (nearest station) or Open-Meteo (ZIP-centroid) for weather; Open-Elevation; OpenStreetMap contributors. Public data retrieved Aug 22, 2026; agencies update their layers on their own schedules. Planning data, not a survey or legal advice.