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

Johnson County requires building permits for new buildings, additions, residential work, renovations, building systems and demolition in county-administered areas¹. A detached one-story tool shed, storage shed, playhouse or similar accessory structure of 200 square feet or less may be exempt; a deck is exempt only if it is no larger than 200 square feet, no more than 30 inches above grade, unattached to a dwelling and does not serve the main exit door¹. Discuss the project with Building Services before construction, and do not start permitted work until the building permit is issued¹. The current FAQ lists the 2024 residential, building, mechanical and plumbing codes, the 2023 electrical code and the 2012 energy code¹. West Branch, mainly in Cedar County but reaching into Johnson County, handles its own building permits; its private sewage rules refer to Cedar County Board of Health standards^12,13.

Planning, Development and Sustainability (PDS) is Johnson County's building department; Building Services issues building permits and schedules inspections for unincorporated Johnson County². Reach Building Services at 319-356-6085 at the Johnson County Administration Building, 913 S Dubuque Street, Iowa City, IA 52240-4281². Inspections include footings before concrete, accessible underground plumbing before a slab is poured, the electrical service panel before hookup and a final inspection when the structure is ready for occupancy¹⁴. Johnson County publishes building-permit fees, including $50 per hour for reinspection and no charge for a certificate of occupancy¹⁵. PDS Planning and Development handles zoning at 319-356-6083². Johnson County Public Health separately handles septic and qualifying private-well permits at 319-356-6040^1,5,16. A Johnson County change-of-occupancy permit requires inspection even when no construction is planned; an approved inspection leads to a new certificate of occupancy¹⁷.

Yes. Johnson County has zoning responsibility outside its cities, including unincorporated villages and fringe areas around incorporated cities; municipal rules apply inside city limits^3,6. West Branch, a city mainly in Cedar County that reaches into Johnson County, sets its own zoning; private sewage systems there follow Cedar County Board of Health standards^13,18. The Unified Development Ordinance publishes 27 districts, and permitted uses, setbacks, building heights and other dimensional rules vary by district^3,19. Iowa law generally exempts agricultural land and qualifying farm structures from county zoning while used for agricultural purposes, although floodplain conditions remain relevant²⁰. Iowa requires the county to allow at least one accessory dwelling unit on a lot with a single-family home in a district where that principal use is allowed, subject to a limit of 1,000 square feet or 50% of the main house, whichever is larger¹⁰. Ask PDS to identify the parcel's district and applicable use, setback and height rules before designing or buying².

Johnson County Public Health administers private sewage disposal and wastewater permits⁴. New development needs sewage approval, the parcel must be tested for treatment suitability, and PDS cannot issue the building permit until Public Health approves the system; approval can take up to 2 weeks⁴. Where public sewer is available or connection is required locally, a private sewage system may not be installed, repaired or rehabilitated; when public sewer becomes available within 200 feet, connection is required on the administrative authority's timetable⁷. Where public sewer is unavailable, an occupied building needs an approved private sewage system, so off-grid sanitation still requires approval and a construction permit⁷. Only 0.4% of Johnson County soils are rated “not limited” for a conventional drain field; that calls for site evaluation and possibly an engineered system, rather than ruling out septic²¹. A certified septic inspection is generally required before an ownership transfer and remains valid for 2 years, subject to listed exceptions and deferrals⁷.

We could not confirm a current Johnson County rule allowing long-term RV living or temporary camping on private land in the unincorporated area, so ask PDS about the parcel's zoning district before moving a camper onto it². We also could not confirm a countywide tiny-home occupancy rule or a numeric minimum dwelling size; setbacks, height limits and other dimensional standards depend on the zoning district^19,22. Iowa does allow manufactured homes, but they must meet the same permanent-foundation, setback and minimum-size standards as a site-built home on the same lot²⁰. Iowa’s own-property contractor-registration exemption does not waive building permits or inspections for an owner-built home⁸. None of those rules turns an RV into an approved dwelling; confirm the proposed structure and use with PDS².

1. Ask PDS Planning and Development to confirm the parcel's zoning district, permitted use, setbacks and height rules^2,19.
2. If dividing land, discuss subdivision review early; plats require an Iowa-licensed surveyor, and some projects need a parallel Secondary Roads filing²³.
3. Ask Public Health whether public sewer must be used or the site can support septic; only 0.4% of county soils are rated “not limited” for a conventional drain field^1,7,21.
4. Obtain sewage approval before the building permit; ask Public Health for a private-well construction permit for a new or replacement well or a change to a well’s physical dimensions^1,4,9.
5. Submit plans to Building Services; ordinary applications may take 5 to 10 working days, excluding projects needing a variance, rezoning or boundary-line adjustment^1,2.
6. Begin work within 180 days of issuance and avoid suspending or abandoning work for more than 180 days; request any justified extension in writing¹. Keep required work visible and accessible for county inspections, including the final inspection when the structure is ready for occupancy¹⁴.
7. For access to an Iowa primary highway, obtain Iowa DOT approval before work begins²⁴.

Johnson County's center is about 17 miles in a straight line from the nearest city of 100,000 or more, and the county has about 257 people per square mile²¹. About 88.7% of the land is at a slope of 15% or less, while 16.4% is wooded²¹. Septic suitability is the sharper constraint: just 0.4% of soils are rated “not limited” for a conventional drain field, so site evaluation is necessary and an engineered system may be needed²¹. Before closing, confirm zoning, subdivision status, legal access, public-sewer availability, septic feasibility, well permitting and any required transfer inspection with PDS and Public Health^1,2,5,7,23. Typical home value is about $313,517, the effective property-tax rate is about 1.6%, and the median annual property-tax bill is about $4,587²¹. A private-well construction permit does not authorize water withdrawal; withdrawals exceeding 25,000 gallons per day may need separate authorization⁹.