Barndominium Builders in St. Mary's County, Maryland
St. Mary's County, Maryland fills the tip of the Southern Maryland peninsula between the Potomac and the Patuxent, and most of it is still farms, woods and tidal creeks. Outside Lexington Park, Great Mills and Leonardtown, the typical homesite is several acres on a well and septic system, which is exactly the kind of lot people want for barndominiums in St. Mary's County. The County's Department of Land Use and Growth Management processes building permits and applies the zoning ordinance across the unincorporated county, and its permit staff route each application to the other agencies that must sign off. The St. Mary's County Health Department runs the perc test and permits the well. Two local rules shape what you can buy: the Rural Preservation District, where extra homes on a parcel need transferable development rights, and the Chesapeake Bay Critical Area, which reaches 1,000 feet in from tidal water on a county with a very long shoreline. Kits suit owners who want to manage their own crew; a turnkey build puts the permits, site work and trades on us. Send the parcel first, and we will check its zoning district, perc history and Critical Area status before anything is drawn.
St. Mary's County at a glance
- Government
- County
- Building permit
- County permit office
- Land use
- County zoning
- Wastewater
- Septic via the county health department
- Private wells
- Well permits from the county health department
Barndominium Kits and Barndominiums for Sale Near St. Mary's County
Finished barndominiums rarely come up for sale, so buying one usually means one of two routes: a steel or pole barn kit delivered to land you own, for an owner or a hired crew to put up, or a new build on your parcel from plan to move-in. A custom plan fits the shop bay and the living space to the lot. Either way the land sets the budget more than the floor area does, so each option is priced against your site rather than a rate card.
Barndominium Kits
Barndominium kits for sale in Maryland: steel and pole barn shell packages for your land, and how a kit differs from a modular or manufactured home.
Custom Plans
Custom barndominium plans in Maryland: floor plans, 3D views and a permit-ready drawing set built around your land, your shop and your budget.
Barndominium Builders and Pole Barn Homes Near St. Mary's County
A pole barn home sets its frame on posts and trusses (the engineering term is post-frame), which often suits a simple, wide layout with a shop bay under the same roof. A turnkey build takes the project from the pad to the finished house. Whether either fits your parcel comes down to the zoning, the septic and the water, set out below.
Turnkey Builds
Turnkey barndominiums in Maryland: land to move-in under one contract, from site work and septic coordination to the finished, inspected home.
Pole Barn Homes
Pole barn homes in Maryland: wood post-frame barndominiums built as permitted houses, from shell to finished home, with or without a shop.
Building in St. Mary's County: Permits, Zoning, Septic and Wells
Four questions decide whether a barndominium works on a parcel before any steel is ordered. Here is who answers each of them in St. Mary's County, taken from the office or document that publishes it. Rules change, so check them again against your parcel before anything is drawn.
St. Mary's County Department of Land Use and Growth Management, Permit Services Division
The Permit Services Division processes building permits, plus the environmental permits for Critical Area and floodplain work, under the County's building code, zoning ordinance and subdivision regulations, and routes each application to the other agencies that must review it.
Source: Permits, St. Mary's County Department of Land Use and Growth Management (stmaryscountymd.gov)
St. Mary's County Department of Land Use and Growth Management
The Comprehensive Zoning Ordinance governs the unincorporated county, so the incorporated Town of Leonardtown falls outside it. Most rural land is in the Rural Preservation District, which exists to protect farming, forestry and aquaculture: low-density homes are allowed, the right to farm is protected against neighbours' complaints, and a full range of public facilities is not planned there.
Source: St. Mary's County Comprehensive Zoning Ordinance (stmaryscountymd.gov)
St. Mary's County Health Department, Environmental Health Division
Every property without public sewer needs a perc test before any building with plumbing starts. If the soil passes, a surveyed plat sets aside an area only for sewage disposal. Since 1 July 2025 new-construction perc applications go to the Health Department, not to Land Use and Growth Management.
Source: Perc Testing, St. Mary's County Health Department (smchd.org)
St. Mary's County Health Department, Environmental Health Division
The Health Department issues well-drilling permits, but only to licensed well drillers, who file the paperwork and the proposed well site. Department staff sample every new drinking-water well, and a certificate of potability issues when the state lab results meet the standards.
Source: Wells and Well Water Fact Sheet, St. Mary's County Health Department (smchd.org)
- Extra homes need development rights
- Under the County's zoning ordinance, a parcel in the Rural Preservation District may take its first dwelling on 5 acres of base density without transferable development rights (TDRs); each further lot or dwelling needs TDRs, one each at up to one unit per 5 acres and more at higher density.
- Building in the Critical Area
- The County's Customer Assistance Guide 9 (revised 27 June 2023) requires a Critical Area site plan showing shoreline, wetlands, forest and disturbance limits, and says a lot created by deed only after 15 March 1978 needs an after-the-fact subdivision plat before a permit for a new home can issue.
Source: St. Mary's County Comprehensive Zoning Ordinance (stmaryscountymd.gov)
Source: Customer Assistance Guide 9: Building Permits in the Critical Area, St. Mary's County (stmaryscountymd.gov)
Metal Building Homes Near St. Mary's County
A metal building home uses a steel frame and steel skin, with the clear span to open up a shop, a garage bay or a great room without interior posts. The structural design is set for your site by the engineer and the building official.
Building on Land Near St. Mary's County
Start with the zoning map. Most rural parcels here are in the Rural Preservation District, where one house on an existing parcel is straightforward but splitting off more lots means buying development rights. Next, find out whether the parcel lies within 1,000 feet of tidal water or wetlands; on this peninsula many do, and the Critical Area review adds a detailed site plan and limits on clearing. Then comes the perc test, whose approved sewage area fixes where the house and shop can go. Pole barn homes and metal building homes suit these lots, as long as the long walls and the drive stay clear of the septic area and the well.
Other places in this part of Maryland
Southern Maryland
- Waldorf
- La Plata
- Charles County
- Calvert County
- St. Mary's County
Have land in or near St. Mary's County? Tell us about the parcel and what you want on it, and we will check it against the local rules before anything is drawn.
Building in St. Mary's County: questions
Start the surveyDo I need a building permit for a barndominium in St. Mary's County?
How much does a barndominium cost in St. Mary's County?
Can I build more than one house on my land in the Rural Preservation District?
Are barndominiums for sale in St. Mary's County?
Keep reading
What usually comes next once you know what St. Mary's County allows.
How Much Does It Cost to Build a Barndominium in Maryland?
Sourced per-square-foot ranges, shell versus turnkey, and the site costs that move the number.
Read itCan You Build a Barndominium in Maryland?
Zoning, farmland, septic, wells and who inspects, before you buy the land.
Read itHow Long Does It Take?
From parcel to move-in, and which steps set the clock.
Read itSources for this page
The published pages behind the St. Mary's County facts above. Rules change, so check the current version with the office before you rely on it.
- Permits, St. Mary's County Department of Land Use and Growth ManagementBuilding permit authoritystmaryscountymd.gov
- St. Mary's County Comprehensive Zoning OrdinanceLand use and zoning; Extra homes need development rightsstmaryscountymd.gov
- Perc Testing, St. Mary's County Health DepartmentSewer or septicsmchd.org
- Wells and Well Water Fact Sheet, St. Mary's County Health DepartmentPrivate water wellssmchd.org
- Customer Assistance Guide 9: Building Permits in the Critical Area, St. Mary's CountyBuilding in the Critical Areastmaryscountymd.gov
Other places near St. Mary's County
Nearby places with their own pages. Across a town line or a county line the permit office, the zoning, the septic and the well rules can change, so each is covered separately.
Building in St. Mary's County?
Start with the survey. Tell us where the land is and what you want on it, and we will come back with which offices decide it, what the zoning allows, and a plan to fit.