Boulder County Board of Adjustment denies Allen's Park setback variance after debate over septic, alternatives

On June 4, 2025, the Boulder County Board of Adjustment denied a variance request that would have reduced the required 25-foot western setback to 12 feet to allow construction of a detached studio at 129 County Road 90 in Allen's Park.

The board's decision followed a staff recommendation to deny the request, a presentation from the property owners and their architect, and more than an hour of questions and discussion. Sam Walker, the planner assigned to the case, told the board that staff found the parcel has developable area outside the setbacks and that the variance criteria — including an “exceptional or extraordinary physical circumstance” — were not met. Walker said, “staff recommend that the Board of Adjustment deny docket VAR 25-0001, the Kersting Mata setback reductions.”

The applicants, property owners Jeffrey Kersting and Denise Mata, and their architect, Thomas Beck, argued the lot's small size, the location of an existing septic leach field and septic tank (permitted in February 2011), and the desire to protect the existing cabin's historic appearance justified the variance. Beck said he “totally disagree[d] respectfully of…