Building permits, zoning and septic rules in Boone County, Iowa

Boone County requires a non-agricultural zoning permit whenever a structure is located, erected, moved, reconstructed, extended, enlarged, converted or structurally altered on non-farming property in unincorporated areas¹. The county's own page does not describe this as a separate building-code permit, and we could not confirm a county building inspection or certificate-of-occupancy requirement, so ask Planning & Development whether the project needs anything beyond the zoning permit^1,9. Zoning permit fees run from a $40 minimum to a $1,500 maximum, and Boone County doubles permit fees when construction starts without a valid permit⁴.

Iowa's state building code includes the 2024 International Residential Code, but the listed circumstances for state inspection do not establish that Boone County adopted a separate county building code¹⁰. A person working on their own property is exempt from state contractor registration, but that exemption does not waive Boone County permits or other local requirements¹¹. Boone County's agricultural zoning exemption requires the land and proposed buildings to be farm-related and dwelling occupants to be primarily engaged in agriculture¹. The exemption covers zoning only; floodplain, county-tile, well, septic, addressing and driveway approvals may still apply¹.

Boone County Planning & Development is the first stop for rural building and zoning questions. The office is at 201 State St., Second Floor, Boone, IA 50036, and its phone number is 515-433-0550⁹. Planning & Development administers the county's subdivision ordinance, zoning ordinance and uniform rural addressing ordinance⁹. Applications are available through the department's online Applications & Permits page⁹.

Separate offices handle site-specific approvals. Boone County Health & Sanitation handles septic permitting and inspection at the same courthouse address and can be reached at 515-433-0506³. The Engineer/Secondary Roads Department is on the courthouse's first floor at the same street address and can be reached at 515-433-0530 for county-road access questions¹². The Boone County Engineer also administers the county floodplain ordinance¹³. Ask Planning & Development which approvals apply to the parcel before finalizing a building plan.

Yes. Boone County zoning applies only in unincorporated territory; incorporated cities may administer their own zoning^1,5. The county has agricultural, residential, commercial, industrial and planned-development districts, so the parcel's mapped district controls². Lot area, setbacks, building height and lot coverage vary by district and use^5,14,15.

For example, an R-1 residential subdivision generally has 35-foot front and rear setbacks, a 12-foot side setback, 30% maximum lot coverage and a 35-foot maximum building height⁵. Those figures are examples, not substitutes for checking the parcel's district and proposed use. Qualifying agricultural land and structures are exempt from county zoning while so used, subject to the ordinance's stated limits^1,5. Land divisions and subdivisions are regulated in unincorporated Boone County, and Planning & Development administers the subdivision ordinance^1,9.

Boone County Health & Sanitation is the county septic authority³. The current county fee schedule lists a $250 package covering the perc test, permit and final inspection; system requirements can vary with the site evaluation and system type⁴. Only about 22.8% of county soils are rated without severe limitations for a conventional drain field, so arrange the site evaluation before fixing the house location¹⁶.

Where sewer service is unavailable, Boone County requires an approved septic system or other approved treatment process⁷. For a qualifying residential transfer, Iowa generally requires a certified septic inspection before ownership changes; the inspection remains valid for 2 years, subject to exceptions¹⁷. State and county authority overlap: county boards regulate private sewage systems, while the Iowa Department of Natural Resources retains concurrent authority¹⁷. Boone County's Sanitation Department issues permits for most private wells, and the listed well-permit fee is $100⁷.

A fixed tiny home used as a single-family dwelling in unincorporated Boone County must be at least 23 feet wide, contain at least 700 square feet and sit on a permanent foundation⁶. District-specific lot size and setbacks still apply^5,14. Recreational equipment or an RV-type unit used as a dwelling requires a location approved under county zoning, while commercial campgrounds and travel-trailer parks follow separate conditional-use rules⁵.

A mobile home may serve as a temporary residence during construction under an 18-month zoning permit⁵. Iowa prevents counties from rejecting a compliant home solely because it is manufactured, but allows the permanent-foundation, setback and minimum-area standards applied to a site-built home on the same lot¹⁸. Iowa also requires the county to allow at least one accessory dwelling unit where a single-family residence is allowed, subject to building rules and size limits¹⁹. Boone County separately limits certain granny flats or mobile homes used as second residences to one per residence for an immediate family member⁵.

1. Ask Boone County Planning & Development to confirm the parcel's zoning district, allowed residential use, lot-area rules, setbacks, height and lot coverage^2,5,14,15.
2. Submit the zoning permit application before work begins; Boone County doubles permit fees when construction starts without a valid permit^1,4.
3. If the proposal needs conditional-use approval, allow for public hearings before the Zoning Commission and Board of Adjustment; applications are due 15 working days before the relevant meeting¹.
4. If public sewer is unavailable, obtain the $250 septic package covering the perc test, permit and final inspection⁴.
5. Ask Health & Sanitation whether the proposed private well needs the listed $100 well permit⁷.
6. Obtain a free entrance permit before installing or extending access on a county-maintained road⁸.
7. Contact the County Engineer about floodplain review when the site is in a regulated flood-hazard area¹³.

Start with zoning: confirm the parcel's district, allowed dwelling type, minimum lot area, setbacks, height and lot coverage with Planning & Development^2,5,14,15. If the seller proposes splitting land, county land-division or subdivision review may apply¹. For a fixed tiny home, verify that the design clears the 23-foot width, 700-square-foot floor area and permanent-foundation requirements⁶. For an RV used as a dwelling, confirm an approved location before purchase⁵.

Evaluate wastewater before choosing the building pad because only about 22.8% of Boone County soils are rated without severe limitations for a conventional drain field¹⁶. Confirm well permitting with Health & Sanitation and access with the road authority; a new or extended entrance on a county-maintained road needs a free county permit^7,8. Check mapped flood hazards with the County Engineer before closing¹³. A typical county home has an effective property-tax rate near 1.4% and a median annual property-tax bill around $2,741¹⁶.