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Stormwater Management Regulation: Amendment (effective February 9, 2016)

All subdivisions, commercial and industrial developments, conditional use permits on agriculturally zoned parcels, and manufactured housing park developments are required to comply with the County’s Stormwater Management regulations, Chapter 8:3.6 of the Unified Development Ordinance. Previously, subdivisions of three or fewer lots and publicly zoned parcels were exempt.

Certain requirements may be granted waiver using the Stormwater Management Waiver Form.

For more information:

Stormwater Management Plan Submittal Guidelines and Checklist

Ordinance change memo

News release

Real-time Flood and Water Quality Data

About Stormwater

Stormwater runoff

What Is Stormwater Runoff?

Stormwater runoff is rainfall or snowmelt that runs off impervious (hard) surfaces such as roads, buildings, and compacted soils. This runoff is collected and conveyed through stormwater systems (usually pipes), or flows as surface runoff directly into our streams, rivers and lakes without being treated. 

Dangers and Risks

Stormwater can pose a risk to our water resources. Pollutants (e.g., sediment, nitrates and bacteria) accumulate on impervious surfaces between rainfalls. Frequent, small rains wash pollutants into streams, rivers and lakes. These pollutants negatively impact water quality. Too much stormwater can also adversely affect infrastructure, weakening bridges and damaging environmentally sensitive areas.


Johnson County requires the management of water quality and quantity through practices that allow more rainfall to infiltrate into the ground or be stored for other purposes (e.g., rainbarrel).


Storm Drain

Stormwater Project Financial Assistance

To Request Assistance or Report A Concern

Contact: Kasey Hutchinson, Soil and Water Conservation Coordinator

Phone: 319-356-6083

Email:  Kasey Hutchinson

Johnson County Administration Building
Planning, Development and Sustainability
913 S Dubuque Street, Suite 204
Iowa City, Iowa  52240

Stormwater Management for Johnson County Facilities

Admin Bioretention Cell 

Overall Plan 

2013 Stormwater Plan 

2013 Stormwater Plan Appendices 

Building-Specific Plans

Administration Building Stormwater Plan 2016

A bio-retention cell (above) helps remove pollutants from stormwater that runs off a nearby parking lot. This stormwater feature is located just south of a parking lot for the Johnson County Administration Building.