12/21/2025
This is essentially the elements which were covered throughout the case. The plantiff HOA argued that a lake is an essential element of an MS4, to prevent erosion and dilute pollutants among other benefits. The defendants argued that wetlands were better or more effective, despite the fact that all plantiff HOA lakes were markedly different now, from when they were each developed over 60 years ago. Both sides made their case, argued their relevant points. It was up to the Jury to decide, not the judge.
The EPA's MS4 (Municipal Separate Storm Sewer System) program regulates stormwater from urban areas, requiring permits (NPDES) for cities and counties to manage pollution entering lakes, rivers, etc., through systems of drains, roads, and ditches, often using green infrastructure for treatment. While MS4s primarily focus on public systems, private lakes connected to or affected by these systems can fall under MS4 regulations, especially concerning post-construction runoff from larger developments (1+ acre) or sensitive areas, often requiring permits, management plans (SWMP), or off-site mitigation like in-lieu fees for developers to meet water quality goals, like phosphorus reduction.
What is an MS4?
An MS4 is a conveyance system for stormwater, including roads, curbs, gutters, catch basins, and storm drains, owned by a public entity (city, county, etc.).
EPA Regulation & MS4 Permits:
MS4 operators need a National Pollutant Discharge Elimination System (NPDES) permit.
They must create a Stormwater Management Program (SWMP) to control pollutants.
This involves public education, monitoring, and implementing control measures like green infrastructure (swales, porous pavement).
Private Lakes & MS4s:
Connection: If a private lake receives stormwater from an MS4 system, or if development around it affects the MS4's ability to meet its permit, it becomes relevant.
Post-Construction Runoff: New developments (1+ acre) discharging into MS4s or sensitive waters often need specific stormwater controls, even if they are private.
Off-Site Management: MS4s can allow developers to manage stormwater off-site or pay "in-lieu fees" to support larger projects that benefit the watershed, like those targeting phosphorus in a lake.
How it Affects Private Lake Owners/Developers:
Permit Compliance: Developers of private properties near or connected to MS4s might need permits for their own stormwater systems.
Pollution Control: Regulations aim to reduce pollutants (like phosphorus) from entering lakes, potentially requiring developers to install treatment systems or contribute to watershed projects.
Public Involvement: MS4 programs involve the public, meaning lake residents might see more focus on stormwater quality in their areas, notes the EPA and the Neponset River Watershed Association.
In essence, private lakes are part of the larger watershed that MS4 programs manage, meaning regulations protect them by controlling upstream pollution and runoff from developed areas.
