Building a barndominium or barn in Kendall County: permitting and site work

Kendall County does not enforce a general building code in the unincorporated county. Instead it runs a development-permit process that covers septic, rural addressing and access, floodplain, outdoor lighting and subdivision platting, and its County Fire Marshal enforces a county Fire Code on commercial buildings. The City of Boerne runs its own building permits inside the city; in its extraterritorial jurisdiction it applies subdivision, platting, stormwater, floodplain and environmental rules, not building permits. For most rural Kendall County projects, the septic permit and the development permit are the steps that matter, not a building inspection.

The on-site sewage facility permit, the septic permit, is usually the binding approval for a rural Hill Country build. In Kendall County it runs through the Kendall County Environmental Health. Located on East San Antonio Avenue in Boerne. Confirm the current phone, email, and the development-permit checklist on the county Onsite Sewage page. Ignore any out-of-state phone result: Kendall County, Illinois shares the name.

Local detail: Kendall County Environmental Health is the local OSSF authority. The septic permit is part of the county development-permit process, so it is usually handled alongside addressing and access. If your parcel is in the southeast of the county near Boerne, read the Edwards Aquifer note below before you design, because the rules can change for those specific parcels.

Visit the official Kendall County page to confirm current forms, fees, and contacts.

The statewide 10-acre exemption does not apply in Kendall County. Section 5.5.C.9.b.iii of the county Development Rules (Development Regulations of November 14, 2022), under the heading for tracts greater than ten acres, says: "A permit shall be required for all On-Site Sewage Facilities within Kendall County's area of jurisdiction regardless of acreage." So a new home on 20 or 200 acres still needs a septic permit before construction starts. The county fee schedule effective September 1, 2023 lists the permit at $300 for a system under 500 gallons a day and $600 at 500 or more. On karst limestone the design usually lands on an aerobic treatment unit. Read at the county's own rules, October 16, 2026; confirm the current requirements with the county before you design.

The TCEQ Edwards Aquifer rule does not reach Kendall County. 30 TAC Chapter 213 was read in full on September 16, 2026: Sec. 213.3(8) defines the Edwards Aquifer across Kinney, Uvalde, Medina, Bexar, Comal, Hays, Travis and Williamson Counties, Sec. 213.22(2) lists those same eight counties for the contributing zone maps, both subchapter titles name them, and TCEQ's application fee form has no Kendall County box. Kendall is named nowhere in the chapter. So a building project here files no Water Pollution Abatement Plan and no Contributing Zone Plan, and carries none of the TCEQ review those add in Comal County next door. Two honest limits. The regulated zones are whatever TCEQ's official maps show, so if your tract sits toward the Comal County line, check the TCEQ Edwards map viewer for your exact parcel. And this is an absence in that one rule, not a finding that Kendall County groundwater is unregulated: your septic design, the groundwater district and the county's own development rules still apply.

The Hill Country sits in the roughly 105 to 115 mph design wind speed band (3-second gust, Risk Category II) under ASCE 7-16, the standard most Texas building codes reference. Most parcels fall between mapped contours, so a designer pulls the exact value for your address from the ASCE Hazard Tool. The local twist is the topographic factor, Kzt: an exposed ridge, hilltop, or escarpment raises the effective wind pressure on a building, sometimes by half again versus flat open ground. A metal or post-frame building on a Hill Country ridge should be engineered for that, which is one reason a sealed design from the builder matters here.

Boerne and Comfort sit on Hill Country limestone, so wells can be deep and water planning matters. Confirm groundwater district registration for any new well, and remember that a well budget and a septic budget both belong in your numbers from the start.

A 1-d-1 open-space valuation from the Kendall Appraisal District lowers the tax valuation on qualifying land, not on buildings. A barn, shop, or barndominium is appraised separately at market value. There is no county square-footage threshold that makes a building permit-free, and ag valuation does not remove the septic or development permit. Ask the appraisal district directly about any structure tied to a qualifying ag operation.

Section 3.1 of the Kendall County Development Rules names six permits for construction: driveway (access), development, dark sky, a Fire Marshal building permit, septic and right-of-way, and it adds that no permit will be issued for a tract that was divided illegally. The county's access and driveway permit page sets the order. The 911 address and the access permit come first, filed together, and only then can an owner apply for the development, septic or well permits. Once the forms and fees are in, the office books a meeting with its Access Coordinator, and an agent you designate in writing can stand in for you with full authority. The fee schedule effective September 1, 2023 lists $100 for each. A house driveway permit is decided by the Road and Bridge Department and expires a year after approval; a drive onto a private road now needs only the address request, and access onto a state highway is a TxDOT permit.

The development permit reaches any man-made change to land, improved or not (Section 3.4). On a single-family lot with no mapped 100-year floodplain it is a minor residential permit at $200 and needs no preapplication meeting; where the floodplain touches the lot it is the residential permit at $300, and the site plan has to show the floodplain line. Either one asks for the deed, the plat or survey, a written description of the project and a site plan with setbacks. It runs one year, a renewal must be requested 30 days before it lapses, and it does not authorize the driveway, work in the road right-of-way or the septic system. The county acts on the septic permit within 30 days once the file is complete, and an aerobic system's file carries a maintenance contract and an affidavit to the public.

In a letter dated March 4, 2026, the County Engineer says the county has no building code for single-family homes and no zoning or land use rules outside the cities. It has adopted a Fire Code, run by the County Fire Marshal: under Section 3.5 of the rules, new commercial construction and substantial site improvements need a Fire Marshal building permit, issued only after the development permit, and the same office signs off occupancy on some non-residential and multi-family buildings. That is the line a barn built for weddings or a business crosses and a home does not. The county's forms page says that from October 1, 2026 its Development Management Office administers the Development Rules in place of the County Engineer.

Kendall County requires a dark sky permit before any new outdoor light goes up (Sections 3.3 and 5.9 of the Development Rules). A single-family lot uses the minor permit, which carries no fee on the 2023 schedule; it takes the fixture specification sheets, a site plan marking each light and, where it applies, an elevation of the house showing where they mount. Filed with a development permit, the two are decided together. The rules trace back to a July 27, 2009 letter from the commanding general at Fort Sam Houston asking the county to limit new night lighting near Camp Bullis, where military medical personnel train in the dark, and Local Government Code 240.032 lets a county near an Army installation do that.

The standards land on the fixtures a barn usually gets. Every outdoor fixture must be full cut-off, sending no light above the horizontal or off the property, and the bulb, lens or reflector may not be visible from a neighbor's land or the road. Color temperature is capped at 3,000 Kelvin, with 2,700 or warmer preferred. The classic barn light with a clear refracting lens is banned unless it carries a full opaque shield or its lens is painted opaque, wall packs must be full cut-off, and mercury vapor lamps are banned outright. A home's porch lights and wall sconces get a narrow pass: they may go unshielded behind a medium to dark semi-opaque diffuser or with a flat-bottomed LED emitter. Outside the five-mile zone around Camp Bullis, a residential property is held to 25,000 lumens per net acre; inside it, the rules call instead for fixtures approved by the International Dark-Sky Association, installed to the maker's specifications. Rodeo arenas, pools and courts sit outside the lumen cap but still need full cut-off fixtures aimed at the surface.

The county's groundwater amendment effective August 31, 2023 replaced the lot table in Section 5.2. A home lot on its own well and septic system must be at least 3 acres with 250 feet of road frontage, and the subdivision may hold no more than one lot per 10 acres, with a 50-foot front setback and 10 feet at the sides and rear. On a public water system with septic the floor drops to one acre and 100 feet of frontage. Any lot on a county road or state highway sets the house 50 feet back, and no part of a platted lot may be narrower than 60 feet. The same amendment makes every plat a water question: because the county lies in a Priority Groundwater Management Area, a plat application is not complete without a groundwater availability report, prepared by a Texas licensed professional engineer or geoscientist on the TCEQ form and showing a supply that holds through the drought of record. On the fee schedule a final plat of up to 50 lots is $3,000 plus $150 a lot, and the report's review is $1,000 plus the consultant's fee. Wells themselves answer to the groundwater district; its rules are on the Boerne page.

That amendment also shortened the list of splits that need no plat. It struck the lender exception, the two-tract split over six acres, the family cemetery exception and the affidavit of land location. Still standing in Section 2.1.F: land kept in agricultural, ranch, wildlife or timber use; four or fewer tracts going to relatives within the third degree; a split leaving each lot above 10 acres, each with 60 feet or more of fee-simple frontage on a state, county or county-standard road; sales through the Veterans Land Board; and a division among co-owners of an undivided interest. Waiving the frontage rule for a family or co-owner split now takes 20 acres before the division, a 10-acre average and no piece under 3 acres, plus a recorded 60-foot roadway easement. The October 23, 2023 amendment added a sale to the neighbor next door, where the piece sold may be any size but the piece you keep must meet the lot rules, and it requires every unplatted split to be registered with the County Clerk with the deed, the metes and bounds description and an affidavit admitting that losing the exception means a full plat.