Johnson County, KS Environmental Rules: Stormwater Management (2026)

Sec. 62-42 makes it unlawful to undertake any land disturbing activity in unincorporated Johnson County, defined broadly to include clearing, grading, grubbing, excavating, filling, and stockpiling material, without first obtaining an LD permit from the director of public works and infrastructure. The permit requirement exempts emergency work needed to address an immediate danger to life or property (unless the director later decides it was not really an emergency), ordinary agricultural land uses, and any land-disturbing activity smaller than one acre, though phased or staged projects that are part of a larger common plan of development are measured as a single site rather than broken into smaller exempt pieces.

Sec. 62-43 spells out what an application must include: a site-specific stormwater pollution prevention plan meeting the KDHE general permit and the county's design manual, a grading plan, pollutant-control measures for materials like concrete washout and fuel, contact information for a retained qualified erosion control specialist, a work schedule, a performance surety, and the permit fee, all sealed by a licensed professional engineer or landscape architect who has completed at least eight hours of certified erosion-control instruction. Sec. 62-44 requires the permit holder's erosion control specialist to inspect the site at least weekly and within 24 hours of any half-inch rainfall, correcting deficiencies within three days.

Beyond the construction-phase LD permit, Article III of Chapter 62 layers on post-construction stormwater quality standards for any project disturbing an acre or more (Sec. 62-79, 62-81), and Sec. 62-82 lets an applicant seek a waiver from the design manual, decided by the board of county commissioners after the zoning board weighs factors such as NPDES compliance and adverse effects on stormwater quality.