Missouri

Buying Land in Franklin County, Missouri

Franklin County, seat Union, is one of the St. Louis metro's growing exurban counties along I-44 -- and, unlike most of the Missouri counties in this project, it has real, actively enforced county-wide zoning. A 2026 fight over how to zone data centers shows exactly how much that zoning framework matters for anyone buying land here.

Real County-Wide Zoning -- Confirm District and Process Before Buying

Case-by-case / verify locally

Franklin County has an actual Planning and Zoning Department, a Planning and Zoning Commission that reviews rezoning requests, Planned Unit Developments (PUDs), and preliminary plats at monthly public meetings, and a Board of Zoning Adjustment for variances -- governed by a full "Unified Land Use Regulations" code. This is a meaningfully more regulated environment than most rural Missouri counties: confirm a specific parcel's current zoning district, and whether your intended use is permitted, conditional, or requires a variance, with the department (636-583-6369) before buying.

A Live, High-Stakes Zoning Fight Over Data Centers (2026)

Case-by-case / verify locally

Through 2026, Franklin County's Planning and Zoning Commission and County Commission worked through -- and repeatedly revised -- proposed zoning amendments to regulate data centers, including a contested draft that would have allowed siting as close as 150 feet from residential property lines and removed public-hearing requirements for future projects. After a lengthy public hearing, the County Commission moved to a multi-year moratorium on new data center applications. If a parcel you're evaluating is anywhere near a possible data-center site (particularly along major transmission/substation corridors), this is an active, unsettled policy area to track directly with the county rather than assume is resolved.

Steady Exurban Growth, With Real New Subdivision Activity Near Union

Generally favorable

Franklin County's population has grown steadily (roughly 104,700 at the 2020 Census to an estimated 106,000-plus by 2023, and projected near 108,800 by 2026), with visible new-subdivision activity -- including a 156-lot McBride Homes development and a separate 198-lot Planned Unit Development near Union -- and increasing urbanization along the I-44 corridor and around Washington and Union. That's a healthier demand backdrop than a declining rural county, but it also means more competition for buildable ground and more likelihood that a given rezoning or PUD process actually matters for a specific parcel's future use.

Real zoning changes the playbook here

Franklin County is a genuine exception among the Missouri counties in this project: it has adopted county-wide planning and zoning under RSMo Chapter 64, administered by a dedicated Planning and Zoning Department at the county's Government Center (400 E. Locust Street, Union, Missouri). The department regulates land divisions, lot-line adjustments, zoning districts, address assignments, road naming, and floodplain administration in unincorporated areas, and the appointed Planning and Zoning Commission reviews rezoning requests, Planned Unit Developments, and preliminary plats at meetings typically held the third Tuesday of the month. A separate Board of Zoning Adjustment handles variance requests. Recent commission actions on the public record include a rezoning and PUD final development plan for a 198-lot subdivision near Highway 100 and Hogan Road in Boles Township, and a rezoning from the 'Y' to the 'R' zoning district for a 13.44-acre tract in Union Township -- concrete evidence that zoning district assignment and the rezoning process here are real, active, and outcome-determinative, not a formality.

That means the first thing to check on any Franklin County parcel is its current zoning district and what that district permits, conditionally permits, or prohibits -- something you generally do not need to worry about in most other Missouri counties covered in this project, where no zoning exists at all. The full Unified Land Use Regulations code is available from the Planning & Zoning Department (a paper copy runs $35), and the department's staff can confirm a specific parcel's district and any pending rezoning nearby that could affect it. See our dedicated zoning page for this county for the deeper detail on the data-center controversy and the subdivision/PUD process specifically.

The 2026 data center fight: what it signals for land buyers

Franklin County spent much of 2026 in a genuinely contentious public fight over how to zone data centers -- large, high-power-demand computing facilities that have been drawn to the county partly by its proximity to St. Louis-area electrical infrastructure and available land along the I-44 corridor. Coverage from Spectrum News, St. Louis Magazine, the Missourian, the Sierra Club, and local radio converges on a rough timeline: proposed zoning amendments were tabled in January 2026 pending further review, a six-month pause was adopted (since a shorter, more restrictive moratorium reportedly could not be enacted without triggering a fresh public-hearing requirement), the Planning and Zoning Commission took up revised proposals at a March 2026 meeting held at Union High School to accommodate public turnout, and after a lengthy public hearing the County Commission ultimately moved to a longer moratorium (reported as three years) on new data center applications while the county does further policy work. Proposed provisions along the way included setbacks as close as 150 feet from residential property lines and removing public-hearing requirements for future data center approvals -- both drew significant community pushback.

For a land buyer, the practical takeaway is not about data centers specifically -- it's about what this episode reveals: Franklin County's zoning apparatus is genuinely capable of both allowing and blocking a major land-use change, and the rules governing a specific type of use can shift meaningfully within a single year. If you're evaluating a parcel anywhere near existing high-voltage transmission infrastructure or a large flat tract that could be attractive to a similar large-scale user down the line, confirm the current moratorium status and zoning-district permissions directly with the Planning and Zoning Department rather than relying on a general sense that "the county has zoning" without checking the specifics for that use and location.

Septic, wells, floodplain, and the county's growth geography

Onsite wastewater treatment (septic) permits for unincorporated Franklin County are handled by the Franklin County Health Department (414 E. Main St., Union, MO 63084; 636-583-7300), whose environmental health program covers onsite sewage disposal alongside food and other environmental health inspections -- the standard Missouri arrangement of a local health department administering the state's Chapter 701 RSMo onsite wastewater program. Private wells fall under Missouri DNR's statewide well-construction rules rather than a separate county permit. Floodplain development permits and administration are handled through the Planning and Zoning Department's floodplain function, which matters here: Franklin County borders the Missouri River (Washington, New Haven) and includes the Bourbeuse and Meramec Rivers, both of which have produced significant flash-flooding and river-flooding events historically, including flooding along the Bourbeuse at Union.

Growth in Franklin County concentrates around Washington and Union and along the I-44 corridor, while the county's western and southern areas remain more rural, with real recreation-economy activity centered on the Meramec River (float trips, canoe/kayak outfitters, and riverfront campgrounds near Meramec State Park) and, in the county's northern reaches near New Haven, the edge of the Hermann American Viticultural Area's wine-trail tourism. Building permits are required for construction in unincorporated Franklin County through the county Building Department (636-583-6384), covering single- and multi-family homes, detached outbuildings, manufactured homes, and other structures -- a meaningfully more regulated baseline than a non-zoned county, and one more reason to confirm a specific parcel's zoning district and required approvals before buying rather than assuming rural land here is unregulated.

What we could and couldn't confirm

Franklin County's zoning framework (Planning and Zoning Department, Commission, Board of Zoning Adjustment, Unified Land Use Regulations, recent rezoning/PUD cases) is drawn from page titles and search-indexed summaries of franklinmo.org, since direct WebFetch access to franklinmo.org, kofo.com, and stlmag.com was blocked by a network egress restriction during this research pass -- confirm any specific procedural detail directly with the department. The data-center moratorium timeline (tabled January 2026, a six-month pause, revised proposals reviewed in March 2026, a lengthy public hearing, and an eventual multi-year moratorium reported around September 2026) is reconstructed from multiple independent news sources (Spectrum News, St. Louis Magazine, the Missourian, Sierra Club, KOFO Radio) that converge on the general sequence but were not independently cross-checked against official county meeting minutes during this pass -- treat the exact dates and the moratorium's precise duration as directionally accurate rather than verbatim, and confirm the current moratorium status directly with the Planning and Zoning Department before relying on it. Population and growth figures are drawn from Census Bureau QuickFacts and Missourian.com reporting.

Verify directly with: the Franklin County Planning and Zoning Department ((636) 583-6369) for current zoning-district status, pending rezoning cases, and the data-center moratorium's current status and duration

Who to Call Before Buying Land in Franklin County

Franklin County has a real Planning and Zoning Department, unlike most counties in this project -- always confirm a specific parcel's zoning district and any pending rezoning or moratorium status directly with that department before assuming a use is permitted. We could not confirm direct emails for most departments from public sources; use the phone numbers and websites above.

Planning & Zoning

Franklin County Planning and Zoning Department

Zoning district lookups, rezoning requests, PUDs, preliminary plats, conditional use permits, and the current status of the county's data-center zoning moratorium.

Phone: (636) 583-6369Official website →

Building & Permitting

Franklin County Building Department

Building permits for construction in unincorporated Franklin County, including single/multi-family homes, outbuildings, and manufactured homes.

Phone: (636) 583-6384Official website →

Environmental Health

Franklin County Health Department

Onsite wastewater treatment (septic) permits and general environmental health questions.

Phone: (636) 583-7300Official website →

Septic / Onsite Wastewater

Franklin County Health Department (Environmental Health)

OWTS/septic construction permits and required soil evaluations.

Phone: (636) 583-7300Official website →

Wells / Private Water

Missouri Department of Natural Resources -- Water Protection Program

Private well construction rules and certified well-contractor requirements statewide, including Franklin County.

Official website →

Floodplain / Stormwater

Franklin County Floodplain Administrator (Planning and Zoning Department)

FEMA flood-zone questions and floodplain development permits for unincorporated Franklin County, including Missouri, Bourbeuse, and Meramec River flood exposure.

Phone: (636) 584-6201Official website →

Assessor / Property Tax