Off-grid site report

Charles County, MD

38.4135, -76.8766 · 138 ft elevation

Read this before you act on anything below. This is my researched starting point for Charles 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 rulesCharles County, MD

Zoning & raw-land occupancy

Varies locallyCharles County has a comprehensive Zoning Ordinance (Chapter 297) administered by the Department of Planning and Growth Management, currently under revision; raw land use depends on the specific zone. source

Dwellings, tiny homes & RVs

Unclear - verifyPermanent dwellings must meet the IRC/IBC as adopted by Charles County, enforced by PGM. Tiny-home ADU permission and RV/THOW permanent occupancy under Chapters 130 and 257 were not confirmed at the ordinance-text level, so ask PGM directly. source

Building permits & codes

RestrictedCharles County has adopted the ICC codes (with local insertions) and the 2020 National Electrical Code; permits go through PGM's Codes, Permits and Inspection Services Division. source

Septic & composting toilets

RestrictedThe Charles County Health Department's Environmental Health Division issues septic permits and inspections under Maryland Department of the Environment delegation; county code supplements, not replaces, state septic law. source

Greywater reuse

Varies locallyNo county ordinance was found expanding or restricting Maryland's state greywater baseline; the Health Department's septic permit form does list a 'Gray Water Sand Mound' system type, folded into standard septic permitting. source

Rainwater harvesting

Generally allowedNo county-specific rainwater ordinance was found; rainwater harvesting appears to follow the Maryland state baseline with no added county restriction identified, though this is not fully confirmed.

Private wells & water rights

Generally allowedThe Charles County Health Department issues well permits and MDE approves groundwater appropriation; in some designated development district zones, wells are treated as interim pending public water availability. source

Living disconnected from utilities

Unclear - verifyIn designated development districts like the R-1 zone near Mattawoman, county code requires eventual connection to public water/sewer once available, making well/septic setups interim there; outside those districts, no standalone off-grid ordinance was found. source

Open the full county page with sources →

Sun30-year normals

Peak-sun hours, annual average: 4.9 hrs/day
Worst month (sizes an off-grid array): 3.5 hrs/day
Yearly output per 1 kW of panels: 1,375 kWh

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Weather1991-2020

Precipitation: 44 in/yr
Heating degree days: 3,818 (moderate)

How far help isstraight-line

Hospital MedStar Saint Mary's Hospital: 15.0 mi
Fire station Dentsville Volunteer EMS, Fire, & Auxuliary: 4.7 mi
Hardware store Lowe's: 11.5 mi
Grocery Weis: 7.7 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 20661).

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.