As one step to keeping Winfield water safe, the city water treatment operations will begin treating the water with free chlorine on Monday July 15th. The annual temporary treatment adjustment should last six or seven weeks. Usually, the City uses a chloramine, a combination of chloride and ammonia sulfate, to purify the water. Over time the ammonia in the mixture deposits a film on the water lines. The process of getting rid of the film – denitrification – is undertaken in July and August, once the temperature in the water at Winfield City Lake rises. The lake is the source of water for most of Cowley County, according to the water department’s website. Due to the size and complexity of the distribution system, some water remains in the lines 10 to 14 days before it is used. During this time, combined chlorine residuals decline. A free chlorine residual remains in the water for longer periods of time without the need to flush the lines. During the process customers may experience a slight change in the taste and odor of the water. The water, however, will remain safe for drinking and all other purposes.