ADU rules in Lenexa

Lenexa's Unified Development Code (Title 4 of the City Code) creates no accessory dwelling unit use, so a backyard cottage cannot be added as a second home on a single-family lot. The code defines the Single-family use as "the use of a lot for only 1 detached dwelling unit," and the residential accessory-use list in Section 4-1-B-24-B still reads "Accessory apartments (reserved for future adoption)." The definitions do include a GUEST HOUSE (a small detached accessory dwelling unit for temporary, not year-round use by nonpaying personal guests), but no zoning district, the Use Regulations Schedule in 4-1-B-22, or the accessory-use list names it, and 4-1-B-22 says unlisted uses "are not allowed." Detached garages, workshops and other accessory buildings remain allowed under 4-1-B-24-F-2, just not as a dwelling.

An attached or internal unit (a basement apartment, addition or converted space with its own kitchen) is the "accessory apartment" that Section 4-1-B-24-B-1 holds "reserved for future adoption"; the matching standards slot, 4-1-B-24-F-1, is also reserved and contains no rules. Because a dwelling unit is defined as a space with "complete and independent facilities for living, sleeping, cooking, dining, and sanitation," a self-contained apartment inside a house would be a second dwelling unit, which the Single-family use (only 1 dwelling unit per lot) does not allow. Two units in one building is a Duplex, a separate principal use permitted only in the planned RP-2, RP-3, RP-4 and RP-5 districts (special use in CC and PMU), not an accessory to a house in AG, RE, RP-E, R-1 or RP-1.

Lenexa sets no ADU size limit because it allows no ADU. For context, non-dwelling accessory buildings in residential districts may not exceed the ground floor area of the house (including attached garages) or 25 feet in height, and in R-1, RP-1 and RP-2 the total ground floor area of all accessory buildings on a lot under 1 acre is capped at 250 square feet per 3,000 square feet of lot area, up to 1,500 square feet (2,000 square feet on lots of 1 to 2 acres). Those caps govern garages and sheds; they do not authorize living space.

No ADU of any form is allowed in Lenexa, so there is no owner-occupancy rule to apply. The reserved accessory-apartment slot (4-1-B-24-F-1) contains no standards of any kind, and Kansas has no statewide ADU owner-occupancy statute. The city's rental licensing chapter (Chapter 2-16) licenses rentals by property and has no primary-residence test.

With no ADU use there is no ADU parking standard. The off-street parking schedule requires 2 spaces per dwelling unit for both Single-family and Duplex uses, so any lawful second unit (a duplex in a district that permits it) carries 2 more spaces.

There is no ADU permit path in Lenexa: accessory apartments are "reserved for future adoption" and no district lists an ADU or guest house as a permitted or special use. Kansas SB 418 (effective 7-1-2026) requires by-right approval of ADUs that meet "the criteria outlined in the zoning code and land use regulations," but it does not itself make ADUs a permitted use, and Lenexa's zoning code supplies no ADU criteria to meet. The city has adopted no SB 418 implementation ordinance and no charter ordinance exempting itself from the act (council agendas through 10-6-2026 and charter ordinances through No. 79 checked).

Since Lenexa allows no ADU, there is no ADU-specific rental rule; the code's GUEST HOUSE definition is itself limited to temporary, not year-round use by "nonpaying personal guests." Citywide, Chapter 2-16 requires a rental license for each rented single-family dwelling, duplex unit or rooming unit, renewed each calendar year, and a short-term rental is any dwelling or portion "offered for rent in whole or in part for a period less than 30 days." Short-term rentals may not be used as reception, party or meeting space and occupants must use the property's off-street parking (Section 2-16-A-7). The city's licensing page adds an occupancy limit for short-term rentals (one person, a related household, or up to four unrelated adults).