City officials have eliminated two controversial options for meeting federal drinking water regulations. The Cobbs Hill and Highland Park reservoirs will not be covered with plastic and no new storage tanks will be built in the parks. Ultraviolet disinfection equipment will be installed at the two reservoirs instead.

The EPA issued new requirements in 2005 for how municipalities can store treated drinking water in open reservoirs - the idea being to reduce the chances of parasitic infections. The options were limited: replace the reservoirs with tanks, cover the reservoirs with plastic, or treat the water with UV disinfection. Covering the Cobbs Hill and Highland Park reservoirs and building water storage tanks in the parks bothered the public, who found those options unsightly.

"The more we researched the options, the more UV made sense in those locations," says Paul Holahan, the city's commissioner of environmental services.

The city will install a liner in the Highland reservoir, and cover and line its third reservoir in Rush, which is not located in a public space.

"The water will still be chlorinated, but the UV at Highland and Cobbs Hill will provide an additional cleaning," says Holahan. "This is the lowest cost solution and the one that will require the least amount of energy."

The city will spend $21 million to make the improvements and annual maintenance will cost between $75,000 and $125,000, says Holahan.

The city still has to submit its plans to the EPA for final approval. Once approved, work on the reservoirs should be completed by 2012.