1009 Rain Garden (Published 9/2018)


Mary Anne Lowndes, Sponsor, WDNR

Perry Lindquist, Team Leader, Waukesha County Dept. of Parks and Land Use

Roger Bannerman, USGS

Jim Baumann, former WDNR

Frank Hassler, Good Oak Ecological Services

Leif Hauge, Waukesha County Dept. of Parks and Land Use

Judy Horwatich, USGS

Eric Jacobson, Aspen Garden and Landscape

Ken Potter, former University of Wisconsin


If you have questions regarding this standard, contact SOC Program Manager Kate Brunner at soc@wisconsinlandwater.org or the Team Leader, Perry Lindquist at PLindquist@waukeshacounty.gov.


















Custodian: WDNR

Goal: Create a new technical standard regarding the use of rain gardens to meet state performance standards.

As a result of recent legislative updates, county shoreland zoning ordinances had to be updated to meet state standards under NR 115. Individual home/lot owners in shoreland zones are now subject to impervious surface limits, and must “treat” runoff coming from new impervious surfaces that exceed those limits (e.g., new home, addition on existing home). “Treating” the runoff would entail the application of stormwater BMPs, such as a rain gardens, pervious pavement, green roofs, etc.

The WDNR will be adopting this technical standard. Anyone using rain gardens to obtain credit for meeting nonpoint performance standards will be able to use the criteria in this document to meet the performance standards. Following this technical standard may also be used to demonstrate compliance with performance standards in local ordinances.

Broad Review Completed: May 2018

Standard Publication Date: September 2018 – Click here to access the final standard

Rain Garden Manual Publication Date: Nov. 2018 – Rain Gardens: A Guide for Homeowners and Landscapers available in a full version and printer-friendly version.

Work Team Status: This team met monthly from December 2016 – March 2017. The team continued revising the proposed text throughout 2017, and the draft was released for public review in April 2018.  Public comments were considered and the final standard was published in September 2018.

Additionally, a subset of members and additional contributors updated the guide Rain Gardens: A How-To Manual for Homeowners, which was first published by University of Wisconsin Extension and WDNR in 2003.


Team Resources:

Rain Garden How-To’s

Rain gardens: A how-to manual for homeowners. 2003. Wisconsin DNR & University of Wisconsin Extension.
How to: Build a Rain Garden. www.AmericanRivers.org
Virginia Rain Garden Manual
New Jersey Rain Garden Manual
Madison, WI – Sizing Commercial Rain Gardens
Georgia Single Family Residence Stormwater Management – Rain Garden excerpt
Dane County Rain Garden Manual
Minnesota Bioretention Guidance
Oregon State University Extension Rain Garden Calculator
Watershed Steward Academy Rain Garden Manual
Watershed Steward Academy Rain Garden Sizing

COMPARISON of various sizing guidance

Other Resources

WDNR Technical Standard 1002, Site Evaluation for Infiltration (2014)
Designed to Fail: How Green Infrastructure Standards Create Conditions for Failed Plantings 
Sizing results from model runs with proposed infiltration and depth criteria.