In 1927, the Des Moines Federation of Women’s Clubs petitioned to the Board of Water Works Trustees to install a municipal water softening plant to save customers money spent on soap and wear and tear on clothes. For the next 20 years there were arguments for and against construction of such a facility and then World War II delayed progress of this project until 1947.
A lengthy feature article titled “City to Enjoy Soft Water in Two Years” appeared in The Des Moines Register in November 1947. It described the advantages of soft water and the method of treatment that would be used, and mentioned that cost of the operation of the plant might have to be financed through a raise in water rates. The state health department engineer was quoted as saying the usual experience is that the added cost of soft water is equaled by the saving in soap alone. He also mentioned additional savings, such as longer life of boilers and water heaters.
In December 1949, the filter and lime softening plant went into operation. It consisted of two underground basins, each with a four million gallon capacity, and the filter building which housed the laboratory, chemical feed operations, and eight filters. The filters resemble small swimming pools, each of which contains 100 tons of gravel and 130 tons of sand and holds approximately 50,000 gallons of water.
In the underground basins, lime is mixed with water to remove minerals and kill bacteria. Then the water was pumped to the filters, where it was cleaned by passing through layers of gravel and sand.
In 1958, the capacity of the filter plant doubled when two lime softening basins and eight filters were added.
The filter and lime softening processes are vital to treating the public water supply and are still being used today.