The Utah County city south of Provo acquired a reservoir last week so it can funnel pressurized irrigation water to its 1,860 homes. All but 350 of those households have been tapping expensive - and precious - culinary (treated drinking) water to keep their lawns green because pressurized irrigation water was not available everywhere.

"This will provide enough irrigation water to supply our pressurized irrigation needs citywide," Mayor James Brady wrote in a statement.

Mapleton once owned the 18-acre reservoir at the eastern end of Maple Street near Dogwood Drive, but it sold the area to the Mapleton Irrigation Co. That company provided water for farms in the southern part of the city.

But the reservoir since has fallen into disrepair as farms began to die out. It will cost the city at least $4 million to prepare the reservoir for use again.

But City Administrator Bob Bradshaw said that doesn't necessarily mean a tax hike is on the way.

"We're hoping to pay for the whole system on a self-financing basis," Bradshaw said, "though obviously there will be a charge to use the pressurized irrigation water. We may have to raise money through bonds and, to that extent, it will have impact on all users of the city."

The move is significant for about 1,500 Mapleton residents whose monthly summertime water bills have reached triple digits from irrigating their yards with culinary water. That price is about six times as high as the 350 households in the northwest who have had access to pressurized irrigation water and pay just $17 monthly.

That has left the majority of homeowners awaiting relief. All homes built in the past seven years - an estimated 1,000 - have the infrastructure necessary to provide pressurized irrigation water. In addition, parts of Springville and Spanish Fork may join in the venture and receive some of the reservoir water.

But Bradshaw warned the relief will not be immediate. It could be 1 1/2 years before the reservoir comes online.

Once it does, Bradshaw said the system will be "a major leap forward" for Mapleton.

Most important, the pressurized irrigation system will reduce the demand on the culinary-water system.

"It's a crying shame," Bradshaw said, "to waste such a valuable resource for keeping the grass green."

sgehrke@sltrib.com