Case studies

Milwaukee Metropolitan Sewerage District

The Milwaukee Metropolitan Sewerage District historically faced 50 to 60 sewer overflows per year. MMSD is supplementing grey infrastructure investments made in the 1980s and 1990s with green infrastructure – including bioswales, permeable pavement, stormwater trees, rain gardens, and more – to help further reduce overflows. MMSD’s investment in green infrastructure could reduce the utility’s future infrastructure costs. In particular, an investment of $178 million for green infrastructure in the agency’s combined sewer service area would result in stormwater capture equivalent to $222 million investment in gray infrastructure. Click the link below to download the full case study.

Project at a Glance

Utility Overview

  • Utility: Milwaukee Metropolitan Sewerage District (MMSD)
  • Location: Milwaukee metro area, Wisconsin
  • Population served: 1.1 million
  • Planning area: 411 square miles


  • Combined sewer overflows
  • Basement backups
  • Stormwater runoff from municipal separate
  • Storm sewer system


  • Comprehensive localized infrastructure strategies across public and private properties

Costs and Funding Sources

  • Total project budget for 2019: $11 million
    • Green purchasing programs: $6.5 million
    • Public property projects: $1.2 million
    • Private property projects: $1.9 million
    • Funding source: Combination of property taxes, rate revenue and MMSD-issued general obligation bonds
  • Total project budget for 2020-2023: $20 million

Benefits of MMSD's Green Infrastructure Programs

Expected to save MMSD in traditional infrastructure upgrades
Helps reduce sewer overflow incidences by 96%, from 50 to 60 per year to only 2.3 per year
Creates 500 green maintenance jobs at full implementation
Produces 160 construction jobs on average per year
Increases property values by an estimated $667 million
Educates the public about water resources and sustainable solutions
Improves environmental health by reducing carbon emissions, conserving energy, and improving air and water quality
Improves quality of life and aesthetics by providing additional green spaces and recreational opportunities

Check out WaterNow’s Tap into Resilience Toolkit to learn even more about investing in localized solutions like MMSD’s in your community.


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