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STORM UPDATE - MAY 17-20, 2020

05/22/20 08:00:am
rain gauge data for may 17 2020

Record rainfall on May 17, 2020 resulted in sewer overflows to reduce the risk of wastewater backing up into homes and businesses.

Mitchell International Airport measured 2.99” on May 17, the highest total for that day ever recorded.

Even higher totals were recorded around the region with the majority of gauges measuring 4” and 5” from May 17 through 20.

One inch of rain on MMSD’s service area equals 7.1 billion gallons.

Total overflow volume for the event was 2.1 billion gallons.

Combined Sewer Overflow 2.1 billion gallons.

Separate Sewer Overflow 14 million gallons.

Additional overflows were reported by Bayside, Brookfield, Brown Deer, Cudahy, Elm Grove, Fox Point, Mequon, Milwaukee, River Hills and Shorewood.


The Milwaukee Metropolitan Sewerage District (MMSD) is reporting the following information to the Wisconsin Department of Natural Resources (DNR).