New Well 25 Enhances City’s Water Reliability and Growth

Published on June 10, 2026

The City of Sioux Falls has placed the newly reconstructed Well 25 into service, restoring a long-standing groundwater site and bolstering the city’s drinking water supply.

The well serves as a key component of the city’s groundwater wellfield system. It delivers water to the city’s water purification plant for treatment and distribution throughout the community. The well increases system capacity by more than 5 million gallons per day, with peak output reaching up to 7 million gallons per day.

“Well 25 strengthens our ability to meet the community’s water needs today and into the future,” said Chris Myers, water superintendent for the city. “The additional capacity helps us keep pace with residential, commercial and industrial growth, maintain reliable service during peak summer demand and continue providing high-quality drinking water to residents and businesses across Sioux Falls.”

Well 25 replaces and modernizes a well originally constructed in 1952 at the same site, located on the north side of town near the Big Sioux River. The original well served the city for more than 70 years. The project converted the location into a horizontal collector well designed to increase production and strengthen long-term system reliability.

Engineers designed the system with six horizontal laterals extending a combined 700 feet into the surrounding aquifer. The configuration expands the collection area compared to the former gravel-packed caisson well and increases the volume of groundwater available while maintaining long-term aquifer sustainability.

“This project combines modern well design with extensive groundwater research to maximize production while protecting the long-term health of the aquifer,” said Nick Borns, principal engineer for the city. “By replacing aging infrastructure with a horizontal collector well, we were able to significantly expand the collection area and restore capacity at one of the city’s most productive groundwater sites.”

Over time, the original well’s capacity declined because of age and maintenance challenges associated with the aging infrastructure. The new well restores reliable capacity and reduces the operational risk associated with relying on an aging well that had become difficult to maintain and was no longer producing near its original design capacity.

For the project, the city partnered with the U.S. Geological Survey to conduct hydrogeologic studies of the Big Sioux River Aquifer to determine the optimal location for a new well. The hydrogeologic studies, which included magnetic resistance imaging and electrical resistivity tomography, confirmed the Well 25 area as a productive groundwater source.

The project was completed in two phases at a total cost of approximately $9.3 million. A significant portion of the project was funded by a federal grant, administered by the South Dakota Department of Agriculture and Natural Resources.

Planning, design, construction, testing and commissioning occurred over multiple years, with major construction beginning in 2023 and the well entering service in 2026.

Well 25 is part of the city's long-term water supply planning and infrastructure investment efforts. It is one of several system upgrades intended to maintain reliable drinking water service and expand capacity to support future growth in Sioux Falls.

For more information on water purification in Sioux Falls, visit siouxfalls.gov/water.