Building permits, zoning and land rules in DeKalb County, Missouri

DeKalb County appears not to require a county residential building permit in unincorporated areas¹. Ask the DeKalb County Courthouse to confirm the rule for the parcel before construction². The county's rules apply to unincorporated land; inside Maysville, a written application and a city building permit are required before construction, alteration or moving of a building³. Cameron, which lies mainly in Clinton County but reaches into DeKalb County, also requires city building permits inside its limits⁹. Colfax Township's building-permit rule is unconfirmed, so ask the courthouse².

Missouri authorizes local code adoption rather than imposing one uniform statewide building code, so a municipality or another authorized local body can change the answer within its jurisdiction¹⁵. Missouri's county land-use statute does not reach incorporated areas or the raising of crops, livestock, orchards or forestry, and farm buildings are exempt only outside the mapped flood hazard area¹⁶. A Missouri protection for farm buildings applies specifically against county fire-protection or fire-prevention ordinances; it is not a blanket exemption from zoning, floodplain or septic requirements¹⁷.

We could not confirm a dedicated DeKalb County building department, permit office, residential inspection process or certificate-of-occupancy process. The practical starting point is the DeKalb County Courthouse at 109 W Main St, PO Box 248, Maysville, MO 64469, or 816-449-5402². Ask the courthouse which jurisdiction covers the parcel and whether a municipality, township, floodplain administrator or road authority must review the work. Inside Maysville the city issues building permits and sets zoning^3,4. For a parcel in Colfax Township, Washington Township or Grand River Township, request the current zoning contact and ordinance before relying on county-level information¹⁰.

Zoning in DeKalb County is set locally, not countywide. The county's townships page identifies Washington Township Zoning, Colfax Township Zoning and Grand River Township Zoning¹⁰. Colfax Township has a Zoning Ordinance that applies to the unincorporated areas of the township, with an official zoning map kept by the Township Clerk⁵. The City of Maysville adopts and administers its own Chapter 405 Zoning Regulations inside city limits⁴, and conditional uses there need approval from the Maysville Zoning Board¹⁸. Washington Township's zoning is listed as a township board responsibility, though its ordinance was not located¹⁹. Cameron, a city mainly in Clinton County that reaches into DeKalb County, regulates land use through its own planning and zoning commission²⁰.

We could not confirm minimum dwelling size, lot size, setbacks or subdivision approval for any of these jurisdictions. Identify the parcel's municipality and township, then obtain the current ordinance and zoning map from that jurisdiction before planning a house, accessory dwelling, tiny home or manufactured home¹⁰.

Missouri DHSS is the listed onsite-wastewater permitting authority for DeKalb County for systems within DHSS jurisdiction⁶. Statewide, either DHSS staff, a local public health agency or an ordinance-adopting county or city may regulate construction and repairs, which is why city limits can differ from the county²¹. Inside Maysville, the city regulates private sewage disposal permits and inspections, and state or county health officer requirements still apply⁷. Cameron requires a written permit from its city superintendent for private sewage disposal inside its limits⁸.

A construction permit is required before installing or repairing most onsite systems, although some single-family residential lots may be exempt; work should wait until DHSS issues a permit or confirms an exemption⁶. Residential property smaller than 3 acres generally requires a permit, but that acreage exemption does not apply everywhere, so confirm eligibility with DHSS²². The mapped soil data show 0% of DeKalb County soils without severe limitations for a conventional drain field, so a site and soil evaluation early on is worth the money¹⁴. State law does not require an inspection of an existing system at a sale, but a lender or buyer may request one, and it must be done by a licensed individual²². Application fees for onsite-system construction, modifications and repairs are temporarily suspended effective August 28, 2026; the permit or confirmed-exemption requirement remains⁶. Contact the DHSS Onsite Wastewater Treatment Program at 573-751-6095 or OnsiteProgram@health.mo.gov⁶.

We could not confirm a countywide rule allowing or prohibiting residential RV use, temporary camping on private land, tiny-home occupancy, manufactured-home occupancy or accessory dwellings in DeKalb County. Do not treat the absence of a published county rule as permission. The answer depends on whether the parcel lies in a municipality or in a township with zoning, and Colfax Township is confirmed as having a zoning ordinance for its unincorporated area⁵. Washington and Grand River townships also have zoning bodies identified¹⁰. Ask the courthouse to identify the governing jurisdiction, then request written confirmation about placement, occupancy, sanitation and time limits before buying or moving a unit².

Any dwelling without central sewer needs an onsite wastewater system, and wastewater may not be discharged into a road ditch or onto the ground²³. Camping at the City of Maysville's reservoirs is prohibited, but that rule covers city reservoirs, not private land²⁴.

1. Confirm whether the parcel is inside a municipality and identify its township, because zoning authority varies across DeKalb County¹⁰.

1. Call the DeKalb County Courthouse and ask for written confirmation of any building, inspection, occupancy, floodplain and county-road requirements tied to the parcel².

1. Obtain the applicable township or municipal ordinance before finalizing siting: Colfax Township's Zoning Ordinance and map are kept by the Township Clerk, and Washington and Grand River townships have zoning bodies whose dimensional rules were not confirmed^5,10.

1. Contact DHSS for a septic application number, site requirements and confirmation of any permit exemption before onsite-wastewater work begins; inside Maysville or Cameron, start with the city instead^6,8.

1. If the site is in a regulated floodplain, obtain the required local floodplain-development permit; work in the regulatory floodway also requires an Engineering No-Rise Certificate before that permit can issue¹³.

1. Resolve driveway authority before construction; we could not confirm a county-road access standard, while state-highway access is regulated by MoDOT²⁵.

DeKalb County’s mapped soils show 0% without severe limitations for conventional septic drain fields, so arrange a site and soil evaluation before committing to a homesite¹⁴. Development in a regulated floodplain requires a permit¹³.

For a private well, Missouri requires permits for regulated well and pump installation work, but allows landowners to install their own well or pump without a permit under applicable law and rules; construction standards still apply¹². A public well in DeKalb County requires written approval from Missouri DNR’s Public Drinking Water Branch before construction or alteration, subject to charitable and benevolent organization exemptions; contact DNR’s regional office for a well-site survey and obtain an estimated casing-depth letter before applying¹¹.

DeKalb County’s effective property-tax rate is about 0.8%, and the median annual property-tax bill is about $1,269¹⁴. Ask the courthouse about county-road access and subdivision review, and identify the applicable township before finalizing a purchase^2,10.