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

At a glance

Building permit

Required for new single-family dwellings, modular homes and single-family room additions in unincorporated Cass County¹

Zoning

County zoning applies outside recognized municipalities²

Septic

Permit required in unincorporated areas from Cass County Environmental Health; $300 for a new residential system⁵

Permit timing

Plan review is required; permits are not issued at application⁴

Owner-builder exemption

We could not confirm an owner-builder exemption; ask the Building Codes Department⁶

Minimum home size

1,000 sq ft of living space, excluding basements, porches and garages; manufactured homes must be 1976 or newer with a federal seal⁷⁸

Septic soil suitability

0% of mapped soils rate without severe limits for a conventional drain field⁹

Minimum parcel size

Set by district: more than 20 acres in A, 3 acres or more in R-R, 1 acre or more in R-S¹⁰

Setbacks

Typically 50 feet front and rear, down to 25 feet on some parcels; sides range from 25 feet down to 6 feet in older small-lot subdivisions¹¹

Who to call

Contact details are copied from each office’s official page and were checked against it on October 13, 2026.

Do you need a building permit in Cass County, Missouri?

New single-family dwellings, modular homes and single-family room additions in unincorporated Cass County require a building permit before work starts; submit the application and supporting information in person to the Building Codes Department¹. Pleasant Hill issues its own residential building permits¹². Lee's Summit, a city that reaches into Cass County, issues its own building permits; its code directs private sewage-system permits to Jackson County Public Works when public sewer is unavailable¹³¹⁴. Cass County Environmental Health's wastewater authority applies to unincorporated land, so confirm the septic permitting agency separately for a city address³. The county adoption document lists the 2006 International Codes and 2005 National Electrical Code but directs applicants to verify current requirements with the Building Codes Department¹⁵.

Who is the Cass County building department, and how do you reach it?

The Cass County Building Codes, Zoning & Environmental Health Department is at 30508 S. W. Outer Road, Harrisonville, MO 64701; call 816-380-8134 during its posted weekday office hours⁴. The department says building permits are not issued at application, so submit early enough for plan review⁴. The published county process says most zoning actions take about 6 weeks through the Planning Board hearing and the following County Commission hearing, while some applications need additional hearings¹⁶. The residential application packet lists $350 total: $300 for the septic permit and $50 for the building application, with an additional service fee for card payments¹. The published fee schedule separately lists a $135 minimum permit fee and a $338 certificate-of-occupancy fee; ask the department which charges apply to the project¹⁷.

Does Cass County have zoning?

County zoning applies outside recognized municipalities in Cass County². Pleasant Hill sets its own zoning, as do Kansas City and Lee's Summit, cities that reach into Cass County¹⁸¹⁹²⁰. City zoning does not establish septic authority; Cass County Environmental Health administers covered wastewater systems on unincorporated land³. Single-family residences there need 1,000 square feet of living space, excluding basements, porches and garages⁷. The county's manufactured-home application applies the same 1,000-square-foot minimum to new homes and home installations, and a new manufactured home must be 1976 or newer and bear a United States Government Manufactured Home Seal⁸. District parcel sizes include more than 20 acres in A, 3 acres in R-R, 1 acre in R-S, and lots down to 1/4 acre in R-1 with public sewers; confirm the full requirements for the parcel¹⁰. Building setbacks vary by parcel: the norm is 50 feet from the front or rear property line, down to 25 feet on some parcels, and side setbacks run from a maximum of 25 feet down to 6 feet in a few older, small-lot subdivisions¹¹. Lots fronting on two streets need a 50-foot setback on each of those sides, and existing and new R-1 subdivisions have different requirements, so ask the department for a site-specific zoning determination¹¹. Newly created lots need direct, owned access to a public road rather than an easement, a 4:1 length-to-width ratio and at least 100 feet of frontage width at the building line²¹. Parcel divisions of any size require a survey; divisions below 20 acres intended for immediate sale and use involve additional review²².

How do septic permits work in Cass County?

Cass County Environmental Health permits onsite wastewater systems in unincorporated Cass County³. A permit is required before construction, modification or repair of an on-site sewage disposal system for a covered system in unincorporated Cass County, and the county lists a $300 fee for a new residential system⁵. The department inspects the septic tank and absorption field before any of the system is covered, with at least 24 hours' notice²³. Missouri separately requires a construction permit before installing or repairing most onsite systems, including residential systems on lots under 3 acres²⁴. USDA soil data rates 0% of Cass County's mapped soils as free from severe limitations for a conventional drain field, so schedule the soil and site evaluation early rather than assuming a standard system will work⁹. For a purchase, Missouri says local agencies generally no longer inspect existing systems for transfers; a private licensed inspector can evaluate the system²⁵.

Can you live in an RV or tiny home on your land in Cass County?

We could not confirm whether RV occupancy or temporary camping is allowed on private land in unincorporated Cass County; ask the Building Codes, Zoning & Environmental Health Department about the proposed use and parcel district²⁴. A single-family tiny home in unincorporated Cass County must meet the 1,000-square-foot living-space minimum, and basements, porches and garages do not count toward that area⁷. The county permits that residential space to be within a manufactured building, which must be 1976 or newer⁸, but meeting the size threshold does not settle a specific tiny-home occupancy proposal⁷. New single-family dwellings require building permits, and covered onsite wastewater systems require county septic permits before construction¹⁵.

Building a home in Cass County: the steps, in order

1. Confirm that the parcel is in unincorporated Cass County and obtain its zoning designation from the county department²⁴.
2. Resolve septic feasibility and apply through Cass County Environmental Health before locking the house and site plan⁵⁹.
3. Submit the building application and plans early because the county does not issue permits when applications are filed⁴.
4. Confirm current fees with the department; the published schedule varies by project type, valuation, size and inspection circumstances¹⁷.
5. Start work and request an inspection within 180 days of permit issuance, then keep work moving because suspension or abandonment for 180 days can void the permit²⁶.
6. Ask Road & Bridge about a drive culvert or entrance, or obtain a MoDOT permit if work enters state right-of-way²⁷²⁸.

What should you check before buying land in Cass County?

Before buying a newly divided lot in unincorporated Cass County, verify direct, owned access to a public road: the county does not accept easements for newly created lots²¹. Cass County regulates development affected by floodplain and stream-buffer areas, and reconstruction or repair in a Special Flood Hazard Area after a flood event requires a building permit²⁹. The terrain is broadly gentle, with 99.4% of land at a slope of 15% or less, but 0% of mapped soils rate without severe limits for a conventional septic drain field³⁰⁹. Cass County is about 19 straight-line miles from the nearest city of 100,000 or more people and has about 160.4 residents per square mile³¹³². Typical farmland value is about $4,459 per acre, while the median property-tax bill is about $2,364 per year³³³⁴.

Watch-outs

• Cass County warns that fraudulent emails claiming money is owed for a building permit or zoning action are a scam; do not respond or send money to unknown recipients⁴.
• A Cass County permit can become invalid unless work begins and an inspection is requested within 180 days after issuance, and a 180-day suspension or abandonment can also void it²⁶.
• We could not confirm an owner-builder exemption; ask the Building Codes Department before assuming you may perform every trade yourself⁶⁴.
• The county fee schedule lists a certificate-of-occupancy fee, but we could not confirm which projects require the certificate; ask the Building Codes Department¹⁷⁴.

Sources

1. casscounty.com, quoted and re-checked
2. Cass County Zoning Department Procedures, quoted and re-checked
3. Cass County Missouri Wastewater Treatment Systems Ordinance, quoted and re-checked
4. Cass County Building Codes, Zoning & Environmental Health Department (casscounty.com)
5. Cass County Missouri Wastewater Treatment Systems Ordinance, quoted and re-checked
6. (2026 county census)
7. Frequently Asked Questions About the Cass County Zoning Order and Subdivision Regulations, quoted and re-checked
8. Requirements for Application for a Manufactured Home Installation Permit, quoted and re-checked
9. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
10. Cass County Zoning Department Procedures, quoted and re-checked
11. Cass County, Missouri Zoning Department Information Guide, quoted and re-checked
12. Pleasant Hill: Building Code Guidelines (Cass County), quoted and re-checked
13. Lee's Summit: Sec. 3.510. Building permit—When required (Cass County), quoted and re-checked
14. Lee's Summit: Sec. 7-119. Sanitary sewer service construction and connection (Cass County), quoted and re-checked
15. Amendments To the 2006 I-Codes, quoted and re-checked
16. Cass County Zoning Department Procedures, quoted and re-checked
17. Amendments To the 2006 I-Codes, quoted and re-checked
18. Pleasant Hill: Planning & Zoning - Pleasant Hill MO (Cass County), quoted and re-checked
19. Kansas City: Kansas City Zoning and Development Code, § 88-110-07, Infill Residential Development Standards (Cass County), quoted and re-checked
20. Lee's Summit: Development Applications (Cass County), quoted and re-checked
21. Cass County Zoning Department Information Guide and Procedures, quoted and re-checked
22. Cass County Zoning Department Procedures, quoted and re-checked
23. Cass County Missouri Wastewater Treatment Systems Ordinance, quoted and re-checked
24. OWTS Construction Permit Process (Missouri statewide rule), quoted and re-checked
25. Onsite Wastewater Treatment System Inspections Versus Evaluations (Missouri statewide rule), quoted and re-checked
26. Amendments To the 2006 I-Codes, quoted and re-checked
27. Cass County Road & Bridge Department (casscounty.com)
28. Permits | Missouri Department of Transportation (Missouri statewide rule), quoted and re-checked
29. Building Codes, Zoning & Environmental Health, quoted and re-checked
30. Share of land at 15% slope or less: Bolthole Index county data
31. Straight-line distance from the county center to the nearest city of 100,000+ people: Bolthole Index county data
32. Population density: Bolthole Index county data
33. Farmland value per acre (USDA census): Bolthole Index county data
34. Median property tax bill: Bolthole Index county data

Written October 13, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.