A Weld County ADU depends on zoning, lot size, and utilities

Many properties in unincorporated Weld County can add one accessory dwelling unit, or ADU, with a building permit. It can be a second house, space inside or attached to the main house, or a unit over a garage.

The utility setup changes the acreage rule. In the Agricultural zone, the minimum is one acre for public water with septic and 2.5 acres for a well with septic. Estate, R-1, R-2, and R-5 parcels can use the ADU path with public water and sewer. A lot of at least one acre may use public water and septic when the nearest sewer line is at least 400 feet away.

Weld County allows no more than one ADU, for two dwelling units total on the lot. The ADU must share the existing driveway; a new driveway is not allowed for it. The unit also has to meet the same building-code requirements as another home.

Before drawing plans, use the address or parcel number to confirm the zone with Planning. Ask the water provider whether another tap is required, or contact the state Division of Water Resources for a well. Weld County Environmental Health handles the septic question, and Building provides the ADU application.