Douglas County expects water demand to increase 45% by 2050, and recommendations in its long-range water plan could change what developers must show before building in unincorporated areas. The county’s 2050 Comprehensive Master Plan recommends heightened review — or possible restrictions — for projects that rely heavily or entirely on nonrenewable groundwater. The county says it wants to protect groundwater supplies, including for drought conditions and rural residents who depend on private wells. The recommendations have not yet been translated into final development rules. The plan sets a goal of supplying 70% of the county’s water from renewable sources, such as rivers and recycled wastewater, while preserving Denver Basin groundwater as a reserve for future drought. Although existing supplies are currently meeting demand, the plan warns that the gap between supply and demand is expected to narrow. The Denver Basin is a system of aquifers that supplies homes, farms and communities across the Denver region. Water providers can legally draw from the basin over a 100-year period, but that does not guarantee every well will produce at its current rate for that long, said Sam Calkins, general manager of Highlands Ranch Water. He said some individual wells in Highlands Ranch have gradually yielded less water over time. Residents who rely on private wells have told county officials they are concerned that additional pumping could further lower aquifers and leave their wells dry. Karen Hickman, a private well owner and member of the Grand View Estates homeowners association, said the group supports restrictions on development when a sustainable water supply cannot be demonstrated. Developers, meanwhile, have raised concerns about how new requirements might affect projects and have asked for clear, workable rules, Commissioner George Teal said. The debate has surfaced in the proposed Crowsnest development, a 745-acre project that could include thousands of homes and commercial space. In July, the county Planning Commission unanimously delayed a decision while seeking more clarity on the project’s water plan. The project’s representative, Dan Williams, said the developer is securing its water supply ahead of the county’s final determination and that current plans call for renewable sources rather than Denver Basin groundwater. Teal said he would support the project moving forward if it can provide a renewable-water plan. Some developers say they are already investing in alternatives. Sterling Ranch, which is planned to eventually house 33,000 people, has built a renewable water system. The development supports the county plan’s recommendations, spokesperson Paul Suter said, adding that the system is intended to help nearby homeowners dealing with declining well supplies. The plan also recommends water-wise landscaping standards and updated building codes. Castle Rock has adopted measures including ColoradoScaping and ultra-high-efficiency toilets for new homes. Local water managers say conservation and reduced outdoor irrigation have helped bring down household water use. The county’s next challenge is deciding whether and how to put the plan’s recommendations into zoning or other regulations. Those decisions could shape the cost, schedule and feasibility of new development — as well as how much pressure future growth puts on the groundwater relied on by existing residents.