Low Impact Development

Low Impact Development (LID) uses a more natural approach to land development and stormwater management. LID design uses a site's natural features and specially designed best management practices to infiltrate stormwater. The intent of LID practices is to get water to soak into the ground and mimic the natural cycle instead of running off into a typical drainage system. However, the success of LID is primarily dependent on the type of soil underlying a site.

The home, business or development that includes LID facilities will have less impact to area streams, wetlands and wildlife habitat. Rainwater can better infiltrate into the ground to recharge drinking water supplies, streams and wetlands. The site is greener and more attractive, with open spaces that appeal to potential buyers. If LID is feasible, the developer or owner will usually save money because the overall infrastructure costs are often less.

Common implementation of LID practices include full or partial infiltration systems and rain gardens, which can be done on either large scale development projects or retrofit into existing residential homes. However, LID can also take the form of more sustainable landscaping designs. Mill Creek has constructed two demonstration gardens near City Hall to serve as examples of what can be done with more natural, sustainable gardening practices.

In conjunction with the State Department of Ecology, the Puget Sound Partnership has prepared a LID Technical Manual that can assist with the design, construction and maintenance of LID systems. Other useful technical resources can be found at the Washington State University Extension office in Puyallup.

Low Impact Development Manual
Rain Garden/Permeable Pavement Maintenance
Ordinance 2017-814 - Mill Creek Municipal Code Amendments that made Low Impact Development (LID) the required approach to managing stormwater runoff where feasible. The revisions are designed to minimize impervious surfaces, native vegetation loss, and stormwater runoff in all types of development situations. The proposed regulations apply citywide.
Rain Garden Handbook 2013