Will County Considers Relaxing Size Restrictions on Accessory Dwelling Units

JOLIET — Will County officials are considering revisions to zoning regulations that would allow larger accessory dwelling units (ADUs), potentially expanding housing options in the county while addressing concerns about current size limitations.

During Thursday’s Land Use and Development Committee meeting, staff presented proposed changes to ADU regulations that would modify the current requirement that limits ADUs to either 49% of the principal dwelling’s size or 650 square feet, whichever is less.

“This is one that hangs us up a lot,” a county staff member told the committee when explaining the current size restrictions.

The proposed changes would create a sliding scale based on zoning districts, allowing larger ADUs on larger properties. Under the current regulations, even owners of larger properties are constrained by the 650-square-foot maximum, which officials acknowledged may be inadequate for many families.

Staff presented a visual demonstration showing how property sizes vary by zoning district, ranging from 10-acre agricultural parcels to one-acre residential lots, explaining how a sliding scale would better accommodate different lot sizes.

“A detached accessory structure could not exceed 1,200 square feet,” a staff member explained when committee member Sherry Newquist asked for clarification on the proposed changes. “So let’s say I had a 2,000-foot house, my accessory structure could not exceed just under a thousand.”

The committee also discussed two additional issues related to ADUs: allowing them in industrial districts and clarifying rules around homes with two kitchens.

Staff explained that while ADUs are technically allowed as a special use in industrial districts according to the zoning text, they are not identified in the use table, creating an inconsistency that needs to be addressed.

Regarding homes with two kitchens, the current practice has been to automatically consider these as ADUs, but staff suggested modifying the rules to acknowledge that some homes have second kitchens for cultural or practical reasons without functioning as separate living units.

“A second kitchen within new construction should not automatically be considered part of an attached ADU unless the construction details indicate it is, such as firewall separation or points of ingress and egress,” staff proposed.

Committee member Sherry Newquist supported this change, noting, “The neighborhood I grew up in and also the neighborhood where I currently live, a lot of the houses are older, a lot of them have second kitchens in the basement from pre-air conditioning days when in the summer you wanted to cook in the basement.”

No formal action was taken on the proposed changes, as the presentation was intended to gather feedback from committee members. Staff will incorporate the committee’s input and present updated language at a future meeting.

The committee also agreed to share the information with the full county board to solicit additional feedback before making final recommendations on the ADU regulations.

ADUs, sometimes called granny flats or in-law suites, have become increasingly popular nationwide as communities seek to address housing shortages and provide more flexible living arrangements for extended families.