Lenexa, KS Environmental Rules: Stormwater Management (2026)

Article 4-5-E of the Lenexa City Code applies to any person proposing new development or redevelopment in the City, who must apply to the Community Development Director for plan approval (Section 4-5-E-2). Section 4-5-E-9 then bars any increase in the quantity and rate of runoff except under an approved plan, requires a Kansas-licensed professional engineer to prepare it, and holds back building permits until the Engineering and Construction Services Administrator signs off.

Review runs in two stages. The preliminary plan is submitted with the preliminary development plan and must meet the Stormwater Management Plan Criteria and Plan Requirements dated July 2017, adopted by Ordinance No. 5678 (Section 4-5-E-10). The Administrator approves it only if the development will not cause flooding outside the existing flood plain during a 1% frequent flood, will not cause or increase flooding of existing structures, will not add unacceptable channel erosion, will not contribute sedimentation to channels or detention areas, and will not create adverse water quality impacts (Section 4-5-E-11). A final plan for each phase, signed and sealed by a Kansas engineer, comes before any building permit (Section 4-5-E-12). The Administrator can waive the plan for a single building or an addition with no significant drainage effect (Section 4-5-E-13). Design follows Section 5600 of the Kansas City Metropolitan Chapter of the American Public Works Association standards, dated February 16, 2011, with Lenexa amendments (Section 4-5-E-15).

Money and upkeep come next. The developer posts an irrevocable letter of credit or other performance bond at 1.25 times the estimated construction cost, released only when at least 90% of the served land area has permanent stabilization and all facilities are built (Section 4-5-E-17). Any portion dedicated to the public carries a 2-year maintenance bond (Section 4-5-E-18). Owners of private facilities must sign a recorded maintenance agreement before a building permit, and the City inspects facilities at least once each year for the first two years and every three years after (Section 4-5-E-21). Appeals go in writing to the Community Development Director within ten working days, then to the Governing Body (Section 4-5-E-24).