St. Louis passes data center zoning law with strict water use and impact fee mandates

St. Louis passes data center zoning law with strict water use and impact fee mandatesSt. Louis has approved comprehensive zoning regulations for new data centers, mandating water usage effectiveness reporting, banning purely evaporative cooling, and requiring developers to fund hydraulic model studies to assess infrastructure impacts.

Board Bill 49 prohibits data centers from operating cooling systems that rely solely on highly water-intensive evaporative cooling.

Developers must enter into written agreements with the St. Louis City Water Division to fund system impact fees and hydraulic model studies prior to receiving building permits.

Data centers are required to achieve and maintain compliance with Metropolitan St. Louis Sewer District wastewater discharge standards.

Major data centers must execute Public Impact Agreements to mitigate site-specific impacts on water usage, wastewater treatment, and stormwater.

On September 11, 2026, the St. Louis Board of Aldermen approved Board Bill 49, establishing comprehensive zoning regulations for data centers that include stringent water supply and wastewater requirements. The ordinance directly addresses the high water consumption typical of data centers by prohibiting facilities from operating cooling systems that rely solely on evaporative cooling. Under the new rules, applicants for standard and major data centers must report anticipated annual water use, as well as peak and average Water Usage Effectiveness (WUE). To protect local utility infrastructure, the ordinance mandates that developers enter into written agreements with the St. Louis City Water Division before a building permit can be issued. Developers are required to fund any system impact fees and cover the costs of a hydraulic model study. This study will be used to identify and rectify any detrimental impacts on existing water customers. Specific fees for data centers or new large load users will be determined by a cost of service study. Wastewater and stormwater management are also heavily regulated under the new zoning framework. Facilities must achieve and maintain compliance with all wastewater discharge standards set by the Metropolitan St. Louis Sewer District. Major data centers—defined as facilities over 250,000 square feet or with a maximum power demand of 30 megawatts or more—must provide third-party environmental impact reports detailing anticipated stormwater impacts and mitigation strategies. Furthermore, major data centers are now subject to mandatory Public Impact Agreements, which require developers to mitigate site-specific impacts on water usage, wastewater treatment, and disposal. These agreements must be approved by the Board of Public Service and the Board of Aldermen. During the meeting, Alderwoman Anne Schweitzer, who sponsored the bill, noted that the regulations were crafted to protect the general welfare and public health of the community. She emphasized that the rules were developed over several months with input from city staff, environmental advocates, and utility stakeholders to address the infrastructure strain caused by large utility users.