Commission recommends allowing accessory dwelling units in R single-family district with conditions

The St. Joseph County Area Plan Commission on April 21 voted to send a favorable recommendation to the county council for APC 3084-26, a text amendment that would add use permissions and development standards for accessory dwelling units (ADUs) in the R single-family district and revise standards for two-, three- and four-family dwellings.

Sean Klein, APC director, described two main parts of the amendment: permitting ADUs (attached or detached) in the R single-family district and updating dimensional and lot standards for multi-family units. Klein said attached ADUs on municipal water and sewer would be permitted by right; detached ADUs on municipal water and sewer would also be permitted by right but would be limited to lots of at least one acre, to be sited behind the primary structure and at least 10 feet from side and rear property lines. Detached ADUs on septic or private well would be allowed only as a conditional use before the Area Board of Zoning Appeals following pre-application consultation with the St. Joseph County Health Department.

Klein summarized specific development standards: an attached ADU shall not contain more than two bedrooms; detached ADUs will be capped to the lesser of 75% of the primary dwelling’s area or 1,000 square feet; when on septic, the property must include 6,000 square feet of undeveloped reserve area to accommodate replacement systems or an ADU system; and detached ADUs on septic would generally be limited to one bedroom to reduce public-health impacts. Klein said staff will flag ADU permits in the county system to preserve undeveloped reserve areas for future septic work.

Commissioners questioned the size and health-department rationale for the 6,000-square-foot undisturbed reserve area and noted that other nearby jurisdictions use smaller reserved areas. Klein said 6,000 square feet reflected what the health department was comfortable with for moving forward and that applicants could request variances through the appropriate board. He also noted the amendment intentionally limits ADU size and bedrooms to keep ADUs ancillary and to reduce impacts on neighboring single-family areas.

Mr. Tavanir moved to send APC 3084-26 with a favorable recommendation; the motion passed by roll call with members recorded as voting yes and the chair announcing the motion carried. The recommendation will go to the county council for formal action and any required public hearings.