ADU rules in Topeka

Topeka's use table (TMC 18.60.010) lists "Dwelling, Accessory" as an allowed use only in the M-1, M-1a, M-2 and M-3 two-family and multiple-family districts and the X-1, X-2, X-3 and D-1 mixed-use and downtown districts. The July 2024 ADU ordinance (Ord. 20500) added an "S/C" entry for the R-1, R-2 and R-3 single-family districts, so a detached ADU there was allowed if it met the TMC 18.225.010(mm) standards (or by conditional use permit if it did not). Ord. 20640, passed February 17, 2026 to loosen multi-family rules in commercial, downtown and mixed-use districts, restated the whole residential table from a pre-2024 copy, and the single-family cell for accessory dwellings is now "-" (not allowed). Section 18.225.010(mm) still describes detached ADUs in single-family neighborhoods and still points to the "S/C" level, so the change looks unintended, but as codified a detached ADU on an R-1, R-2 or R-3 lot has no listed approval path; confirm with Topeka Planning and Development before designing one. ADUs are never listed in R-4, RR-1, OS-1, U-1, MS-1, D-2, D-3 or the office, commercial and industrial districts.

Integrated accessory dwellings (a conversion or addition within or onto the principal dwelling, such as a basement or attic unit) follow the same district rules as detached ones: listed as allowed in M-1, M-1a, M-2, M-3, X-1, X-2, X-3 and D-1, and in the R-1, R-2 and R-3 single-family districts only under the 2024 "S/C" entry that Ord. 20640 dropped from the table in February 2026. Under TMC 18.225.010(mm)(4)(iii) an integrated ADU must be separated from the house by a wall, floor or ceiling, have its own exterior entrance that is not visible from the street on the house's street-facing elevation, keep any exterior stairway on the side or rear, and match the house's windows and eaves. An integrated ADU that cannot meet those standards may seek a conditional use permit.

The use table's description of the accessory dwelling use reads "not exceeding 600 sq. ft." again since Ord. 20640 (Ord. 20500 had changed it to 800 in 2024). The ADU standards in TMC 18.225.010(mm)(4) cap a detached ADU at 800 square feet, excluding garages attached to it, or 50 percent of the principal dwelling's gross floor area, whichever is less, and an integrated ADU at 800 square feet and no more than 80 percent of the principal dwelling's area; but (4)(i) applies those numbers to ADUs at the "S/C" approval level, which the codified table no longer assigns anywhere. A detached ADU is also a detached accessory building, limited in residential districts to 15 feet tall when the house is one story or 20 feet when it is two stories or more, with 3-foot side and 5-foot rear setbacks and 6 feet from other buildings; second-story ADUs over detached garages must meet those height limits. Until the city reconciles the table and the standards, 600 square feet is the conservative figure.

TMC 18.225.010(mm)(5) requires that either the accessory dwelling unit or the principal dwelling unit be occupied by an owner of record of the property. It is phrased as a continuing condition of the use, not only an application-time test, and the owner may live in either unit. Unlike the size and design standards in (mm)(4), which are expressly limited to "S/C" ADUs, paragraph (5) carries no applicability limit. Paragraph (12) lets an ADU that cannot meet (mm)(4), (5) or (6) seek a conditional use permit, so owner occupancy can in principle be relieved only through a discretionary Governing Body approval. Kansas has no statute preempting owner-occupancy rules.

TMC 18.225.010(mm)(7) requires one off-street parking space on a hard surface meeting City standards in addition to the parking required for the principal dwelling (1 space for a house of 950 square feet or less and 2 for a larger one under TMC 18.240.030). On lots with a single street frontage under 100 feet, the ADU's parking and driveway access must come from the existing driveway, or from the alley where the lot abuts one; corner lots and alley lots may integrate it with the existing access, use the other street frontage, or take access from the alley. Kansas has no ADU parking preemption.

Where an ADU is listed, review is ministerial: under TMC 18.225.010(mm)(10) the Planning and Development Director reviews the building permit application and determines whether it meets the ADU standards, and in the M, X and D-1 districts the use is marked as an allowed use. An ADU that cannot meet the size and entrance standards, the owner-occupancy rule or the design guidelines in (mm)(4) to (6) may instead seek a conditional use permit under Chapter 18.215 TMC, which goes to the Planning Commission for a recommendation and the Governing Body for decision. 2026 SB 418 (effective 7-1-2026) requires by-right approval of ADUs that meet the zoning code's criteria, which matches Topeka's existing building-permit review; it applies only to projects that already comply with local land use rules, so it does not supply an ADU use in the single-family districts where the codified table now lists none. The owner must also obtain a separate address or unit number for the ADU from Planning and Development ((mm)(11)).

Topeka has no rental license or registration ordinance (code searches for "rental registration" and "rental license" return nothing), so the ADU-specific limit is the owner-occupancy rule in TMC 18.225.010(mm)(5): one unit may be rented long term while an owner of record lives in the other. Short-term residential rentals (stays of no more than 28 consecutive days) are a separate use: Type I (owner-occupied, meaning the owner resides there 182 or more days a year) and Type II (non-owner-occupied), each up to five guest bedrooms, are "S/C" in R-1/R-2/R-3, M-1 and M-1a and allowed outright in M-2, M-3 and D-1, with an administrative permit from the Director valid for two years under TMC 18.225.010(z) and (aa); a new Type II in an R, M-1 or M-1a district must be at least 500 feet from another Type II or Type III rental. The code does not say which STR type applies when the owner lives in the main house and rents the ADU nightly; confirm with Planning. Nothing in the ADU section addresses separate sale, but by definition the ADU sits on the same zoning lot as the principal building.