Starting Jan. 1, non-residential properties will start being billed for their paved or “impervious” surfaces by the St. Louis region’s sewer utility — equipping it with funding designated to address stormwater, flooding and erosion issues across the area.
The new charge was approved by voters in April as “Prop S,” and was formally adopted by the Metropolitan St. Louis Sewer District at its board meeting last week. Its approval follows years of discussion, past rejection at the ballot box, and the occurrence of increasingly frequent and severe flood issues in the region — problems that no single entity has generally had clear responsibility or specified funding to tackle.
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Beginning in the new year, however, bills for non-residential MSD customers will include a charge of $1.05 for every thousand square feet of impervious surface area, like parking lots and roofs, that doesn’t absorb water and instead contributes to stormwater runoff. Revenue collected through the charge will fund a list of MSD projects aimed to improve local flooding and erosion issues.
One acre of an impervious surface “generates just under 1 million gallons of stormwater runoff per year, assuming an average annual rainfall total of 34 inches,” said Bess McCoy, an MSD spokeswoman, in an email.
The utility has an online tool that shows what individual, non-residential properties can expect to pay in impervious surface charges.
The total expected bill for some of the area’s biggest owners of paved and impervious surfaces wasn’t immediately clear, since many big properties are broken into multiple parcels.
“For example, the Galleria has 17 different parcels on it,” said McCoy, referencing the Richmond Heights mall. “Combined, they’ll pay a monthly bill of about $1,755.”
Meanwhile, St. Louis Lambert International Airport appears to be on the hook for a monthly bill of just over $9,000 for its more than 8.6 million square feet of impervious surfaces, though an assessor update is pending for the site, according to MSD’s website.
St. Louis’ Ikea faces an estimated monthly bill of $778. And the parcel that encompasses the Starr Lot, a large parking lot just south of Busch Stadium, will owe about $218 per month, alone. (The stadium, itself, faces a $615 monthly charge.)
The passage of Prop S also means that, by the end of 2025, residential customers will see their own new charges to raise funding toward the MSD initiative.
The residential customer charge, however, will first appear on property tax bills in December 2025. It will tax customers 7.45 cents for every $100 of assessed valuation at a given property — adding up to about $25 per year for a typical residential property owner, according to MSD.
View life in St. Louis through the Post-Dispatch photographers' lenses. Edited by Jenna Jones.
