The Nitrate Removal Facility is an important part of Central Iowa Water Works (CIWW)’s regional drinking water system. Located at the Fleur Drive Water Treatment Plant, the facility removes nitrate from treated water to help ensure the drinking water supply remainsreliable and meets all state and federal standards.
Nitrate levels in the Raccoon River, the Des Moines River, and the Infiltration Gallery*, all sources of water used at the Fleur Drive Water Treatment Plant, can increase throughout the year. When this occurs, the Nitrate Removal Facility is used to treat water and reduce nitrate concentrations. This allows CIWW to continue providing drinking water that meets state and federal standards, even when nitrate levels in the source water exceed 10 mg/L. Drinking water provided by CIWW and its twelve member agencies has met the nitrate standard for more than three decades and has averaged below 5mg/L for more than 20 years.
Q: What is the Nitrate Removal Facility?
A: The Nitrate Removal Facility is a specialized treatment system that removes nitrate from drinking water to ensure it meets safe drinking water standards. The facility includes eight treatment vessels and can process up to 10 million gallons of water per day. When operating, at least three vessels run at a time, and up to seven can operate simultaneously, with one vessel reserved for regeneration (or cleaning).
Q: How does the Nitrate Removal Facility work?
A: The facility uses an ion exchange process. Water flows through large vessels filled with a special resin that removes nitrate. When the resin becomes saturated, it is cleaned using a salt solution (brine) so it can be reused. The treated water is then blended with other finished water to ensure it meets all state and federal drinking water standards before being delivered to customers. The brine, containing salt and removed nitrate, is sent to the Des Moines Metropolitan Wastewater Reclamation Facility (WRF).
Q: Why is nitrate removed from drinking water?
A: Drinking water standards limit nitrate to protect public health, especially for infants and sensitive populations.
Q: When is the facility used?
A: The Nitrate Removal Facility is typically used when nitrate levels in source water are elevated, and additional treatment is needed to meet drinking water standards.
Q: Does this mean my water is safe?
A: CIWW continuously monitors and treats water to ensure it meets all state and federal drinking water standards. The Nitrate Removal Facility is one of several tools used to maintain high-quality, reliable water.
Q: Why is this important?
A: The Nitrate Removal Facility helps:
- Ensure drinking water meets safety standards
- Maintain reliable water service during periods of higher nitrate levels
- Provide flexibility to manage changing source water conditions
- Support consistent, high-quality drinking water for the region
Q: How much does it cost to operate the Nitrate Removal Facility?
A: When operating at full capacity (seven vessels), the Nitrate Removal Facility costs approximately $16,000 per day to run. In 2025, the total annual cost was about $2.2 million, including $1.6 million in operations and maintenance and $600,000 in capital costs. In the first quarter of 2026, operations and maintenance costs were approximately $660,000. The 2026 capital costs will be calculated in early 2027.
* Q: What is the Infiltration Gallery at the Fleur Drive Water Treatment Plant?
A: The infiltration gallery is a riverbank filtration system located in Water Works Park that collects naturally filtered water from the Raccoon River. It uses 48” underground pipes to gather water that has passed through sand and gravel, where it is naturally filtered before being sent to the Fleur Drive Water Treatment Plant for final treatment.