Source Water Assessment Program – **Illinois Deadline is July 26, 2023**

February 21, 2023

The federal Safe Drinking Water Act and its amendments require states to develop and implement a Source Water Assessment Program (SWAP) that aims to protect all water sources for public supplies.

IL Administrative Code Title 35 Part 604.3 Subpart C contains a schedule indicating when water systems are required to comply with the SWAP prerequisite. Supplies serving between 3,000 and 49,999 users are required to have an updated SWAP by July 26, 2023 (for Illinois). The SWAP then needs to be updated every five years thereafter. Often, funding depends on having a current SWAP in place.


  • Identifies the sources of public water supplies;
  • Establishes one-year and five-year protection areas above the aquifer (in groundwater systems);
  • Inventories potential sources of contamination in the aquifer protection zones and/or within a contributing watershed;
  • Classifies the susceptibility of the source water to contamination;
  • Educates the public on being part of clean water preservation;
  • Assists in developing monitoring plans and protection strategies to ensure safe water supplies.

More than 12 million people in Illinois rely on public water supplies for drinking water. Illinois is served by more than 1,700 community water supplies and 3,800 non-community water supplies. The sources include surface water, groundwater, Lake Michigan, and mixed supplies. All are required to have a current SWAP, unless they purchase 100% of their water from another community. If water-purchasing communities have backup water sources, they too are required to have a current SWAP, even if they are never used.

Beyond the state requirements, a SWAP is a best practice and demonstrates to the community’s residents the will to protect its water supplies. By working to ensure safe drinking water supplies, the health and economy of the community is protected.

V3 has the experts and the experience to work with a variety of public water supplies. We are currently performing, or have recently completed, SWAPs for sources in several states. We are happy to discuss the SWAP requirements and process, and we look forward to helping communities both satisfy the requirements and make a difference in the security and quality of their water supplies.

Questions? Contact Stuart Dykstra at to find out how this applies to you.