Dale Maffitt Reservoir was constructed in the 1940’s and is a 200-acre man-made water storage reservoir located southwest of Des Moines. While the lake is open for recreation, the Maffitt Reservoir is owned and operated as part of the regional drinking water system and plays an important role in how Central Iowa Water Works (CIWW) manages both water quality and reliability.
When excess source water is available at McMullen Water Treatment Plant, water is pumped from the wells and Crystal Lake into the reservoir and stored. This is typically done in the winter months when customer demand is lower. This stored water provides a reserve supply that can be used at the McMullen Water Treatment Plant when river water quality is less favorable, during dry periods, or when customer demand increases.
Q: How does the water get into the reservoir?
A: Water is pumped from the McMullen Water Treatment Plant into the reservoir when river conditions are suitable for storing water as a backup supply.
Q: Why store water in the reservoir?
A: Storing water allows Central Iowa Water Works to use it later when:
- River water quality is more challenging (such as higher nitrate levels)
- Customer demand is high
- Source water supply is limited, such as during a drought
- More options are needed to manage the water system
Q: Does the reservoir improve drinking water quality?
A: Yes. Water stored in the reservoir is lower in nitrate and can be blended with our other source water and be used at the McMullen Water Treatment Plant to help maintain safe drinking water standards.
Q: Why is this important?
A: Maffitt Reservoir helps provide:
- Additional low nitrate water to blend with higher nitrate water from the wells and Crystal Lake during periods of poor water quality
- Reliable supply during peak demand
- Flexibility to respond to changing conditions