Iowa Passes New Law on Topsoil and Stormwater Regulation on Construction Sites

On Wednesday, April 10, 2024, Governor Kim Reynolds approved Senate File 455. This new law, available here, limits the ability of cities and counties to regulate topsoil and stormwater on construction sites.

Senate File 455 amends existing Iowa Code Sections 331.301 and 364.3, each providing identical limitations for counties and cities respectively. Under these new limitations, counties and cities cannot adopt or enforce any regulation relating to the preservation, compaction, placement or depth of topsoil at a construction site that is more restrictive than the requirements contained in the National Pollutant Discharge Elimination System (NPDES) general permit no. 2 issued by the Iowa Department of Natural Resources (IDNR). However, counties and cities may request that the IDNR review the topsoil at a construction site to ensure compliance.

Further, counties and cities may adopt and enforce stormwater regulations concerning water runoff from upstream properties adjacent to construction sites only to the extent such runoff is allowed to pass through downstream stormwater basins at the same flow rates as off-site runoff entering the construction site. Stricter regulations are allowed only if (1) the city or county pays for all related study, design, and engineering costs, (2) the city or county pays for the difference in any added equipment costs, and (3) the city or county compensates private property owners for any impact caused by the regulations (without imposing any other penalty or assessment on the property owner).

This new law is set to take effect on July 1, 2024.

If you have questions regarding this new law or construction law in general, please contact Jodie McDougal (, 515.242.8971) and Jack O’Brien (, 515-242-8931).

  • Jackson G. O'Brien

    He takes a comprehensive approach to each case, ensuring his clients know their options, feel empowered and informed to make their own choices and rest assured that their matters are in capable hands.

    Both inside and outside the ...

  • Jodie Clark McDougal

    In her construction work, Jodie counsels clients within the commercial and residential construction industries including general contractors; homebuilders; construction management companies; architectural, engineering ...

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