Lyon County, NV Environmental Rules: Stormwater Management (2026)

Lyon County Community Development administers mass grading permits under chapter 240 of Title 15 of the Lyon County Code. Section 15.240.01 defines a mass grading permit as authorization to start on-site grading for a new or altered non-residential development ahead of the building permit that will follow, standing in for a combined building/grading approval. Section 15.240.02 requires the Community Development Department to first approve all other required land-use entitlements before a mass grading permit can issue, and blocks issuance for any use inconsistent with the site's current zoning.

The stormwater trigger sits in § 15.240.04(A)(4): once a proposed grading project will disturb more than one acre, or disturbs less than an acre but is part of a larger common plan of development or sale that will eventually reach one acre, the applicant must submit a Storm Water Pollution Prevention Plan approved by the Nevada Division of Environmental Protection, Bureau of Water Pollution Control (NDEP-BWPC), as part of the grading-permit package. Section 15.240.03 exempts several categories from the permit altogether, including grading under 50 cubic yards, clearing and plowing tied to active agricultural production, and grading already covered by a building or encroachment permit, though an exemption from the permit itself does not excuse compliance with every other County Code and land-use requirement still applicable to the site.

A mass grading permit expires if work has not started within 180 days, or if it stalls for 180 days after starting, under § 15.240.05, and fees for the permit are set by Board of County Commissioners resolution under § 15.240.06.