GOLDEN - Jefferson County commissioners on Tuesday rejected proposed groundwater assessment rules for new mountain homes because a requirement to monitor nearby wells during yield tests on new wells had been dropped.

"What you've got now doesn't do it," said Jim Peterson, a career geologist and president of the Bear Mountain Homeowners Association. "All it does is put lipstick on the pig."

The county's planning and zoning division had proposed the revised Mountain Groundwater Overlay District after a series of hearings last year on how to promote sustainable development and an adequate water supply for homes in the foothills and mountains.

The district would include the land west of the Dakota Hogback above 6,400 feet, which is the county's fastest-growing area. About 100,000 people currently live in the proposed district.

The area relies on wells drilled in randomly fractured rock formations.

"The key issue is sustainability," said Peterson.

The proposed rules would have required a pump test to see if an individual well had sufficient flows for each home.

But the planning and zoning division removed a requirement that nearby wells also be monitored during the test to assess the impact of the new development.

Patrick O'Connell of the planning division said that was because the monitoring test results didn't provide a complete picture of the water supply, which varies throughout the year and from year to year.

Furthermore, they weren't cost-effective.

He said the cost of the tests would vary from $500 for a single home to $150,000 for a subdivision with more than 200 homes.

But Dick Burrows, of Conifer, contended that "the monitoring wells are important. We need to understand that we generate regulations after there is a problem.

"There are plenty of people up there who already have a problem with their wells."

Not everyone in the audience of 40 at the commission meeting agreed, however.

"There is no known technology to measure water supply in fractured rock," said Robert Longenbaugh, a Lakewood engineer.

"I don't understand why Jefferson County would want to take on control of well pumping. It is a terrific headache," he added.

For some homeowners, though, including those in Bear Mountain and Indian Hills, new wells drilled in the mountains already have caused headaches.

After new developments were built and wells dug, flows to existing wells diminished or stopped.

"I depend on my well. My neighbors depend on their wells. If someone drills a deeper well, that has a potential impact," said Dave Waddington, of Coal Creek Canyon.

The commissioners voted unanimously to return the proposed groundwater district rules to the planning division to review the value of hydrogeologic reports on nearby wells during flow tests.

frazierd@RockyMountainNews.com or 303-954-5308