ADU rules in Waukegan

Waukegan allows a detached backyard ADU, but only in the R1, R2, R3, R4, R5, L1, L2 and L3 districts, only on a zoning lot that already contains a single-unit dwelling, only in the rear yard, and only after a site plan review hearing. Table 9.03-1 of the Unified Development Ordinance marks 'Accessory Dwelling Unit (Detached)' with an S (site plan review) in those eight districts and leaves the cell blank everywhere else, and UDO 9.03.B.4 says a blank means the structure is not allowed in that district. So ADUs are off the table in the CR conservation district and in every business district (B1, B2, B3, B4, H/C, E) and industrial district (R/LI, I). One ADU is permitted per zoning lot, and the general accessory rules put it at least five feet from any lot line with accessory structures plus impervious surfaces capped at 40 percent of any yard.

The UDO authorizes only a detached ADU. The defined use is 'Accessory Dwelling Unit (Detached)', described in Section 13.02 as a unit 'detached from and secondary to' the main house, and 9.03.C.1.a permits it only 'as a detached accessory structure'. There is no basement, attic, attached-addition or internal-conversion ADU use anywhere in the ordinance. The separate route to a second unit inside the house is the principal use 'Dwelling: Two-Unit (Attached)', permitted by right in R2, R3, R4, R5, L1, L2 and L3 under Table 9.02-1 but not allowed in R1 or CR; that is a full two-flat conversion subject to the district's bulk rules, not an accessory unit, and it carries none of the ADU size or owner-residency standards.

UDO 9.03.C.1.c caps an accessory dwelling unit at 900 square feet. Two further limits usually bind before that number does: 9.03.C.1.d says an ADU 'may not be larger than the principal structure', and the general accessory rules at 9.03.A.4 and 9.03.A.5 bar any accessory structure from exceeding the height of the principal structure or being 'larger in area or any dimension than the principal structure'. Coverage is the third gate: the ADU, all other accessory structures and all paved surfaces count toward an impervious cap of 40 percent of the yard in aggregate. The ordinance sets no separate minimum lot size for an ADU, so the district minimums apply (40,000 sq ft in R1, 7,200 sq ft in R2, 5,000 sq ft in R3 through R5).

UDO 9.03.C.1.f requires that 'the owner of any Accessory Dwelling Unit must maintain primary residency on the same zoning lot as the unit'. This is an ongoing condition on the use, not a one-time test at application, and it is reinforced by the second sentence of the same paragraph, which requires the rental license for any rented ADU to be held by the owner of the zoning lot. Illinois has no statewide ADU statute, so nothing preempts the requirement; it stands as written.

UDO 9.03.C.1.e says an ADU 'counts as an additional dwelling unit when calculating residential parking requirements', and Table 10.03-1 sets the residential minimum at 1 space per dwelling unit, so a house with an ADU needs two off-street spaces. Two carve-outs can erase the extra space: UDO 10.02.C.3 says the minimum vehicle parking requirements 'do not apply to new developments located within one half-mile of a public transportation hub', and 10.02.C.2 drops the residential minimum to 0.5 spaces per dwelling unit in the L1, L2 and L3 lakefront districts. The UDO does not define 'public transportation hub', so confirm with the Zoning Administrator rather than assuming a Metra or Pace stop qualifies. Tandem parking is available for residential uses but only through the same site plan review application. PA 104-0457, Art. 5 (People Over Parking Act), effective 6-1-2026, bars any unit of local government from imposing or enforcing minimum automobile parking requirements on a development project (a permit to construct or reconstruct a dwelling qualifies) within one-half mile of a public transportation hub (any rail transit station, or an intersection of 2 or more bus routes with combined 15-minute peak frequency) or one-eighth mile of a 15-minute-peak bus corridor, binds home-rule units (Section 5-90), and grandfathers site plans approved before the effective date (Section 5-15(b)). The Waukegan Metra station is a rail transit station under the act, so the half-mile hub zone plainly covers part of the city; within it the one-space ADU minimum cannot be imposed on new ADU construction (pre-6-1-2026 approved site plans grandfathered). This state overlay is independent of the UDO's own 10.02.C.3 waiver near an undefined public transportation hub: the act supplies its own definitions and controls regardless of how the city construes its waiver.

Formally this is site plan review, not a conditional use permit, but it is a discretionary public hearing rather than a staff sign-off. UDO 9.03.C.1 states flatly that 'accessory dwelling units are subject to site plan review', and 4.09.B.1 lists 'new construction of an accessory dwelling unit in any zoning district' as the first trigger for the process. The Zoning Administrator takes the application and writes a report, then the Development Review Board holds a public hearing (noticed by first class mail or hand delivery to owners within 250 feet plus a posted sign under Figure 2.07-1) within 60 days and approves, approves with conditions, or denies against the eight standards in 4.09.F, which include consistency with 'the existing character and zoning of adjacent properties' and architecture that 'will contribute positively to the City's aesthetic appearance'. The Development Review Board decides; no City Council vote is required, though the board may vote to refer an item up to the Planning and Zoning Commission or City Council. Approval lapses if no building permit issues within one year, with one six-month extension available.

The UDO assumes ADUs are rented: 9.03.C.1.f requires the rental license for any rented ADU to be held by the owner of the zoning lot, which pairs with the owner-residency rule to bar an absentee-landlord ADU. Sec. 14-4(a) of the Code of Ordinances requires every rental housing property in the city to be licensed, expressly including owner-occupied properties of two units or less, and the city charges $60.00 per rented unit with annual renewal by December 31, Planning and Zoning pre-approval and a Building and Code inspection. Short-term rentals are legal but separately licensed under Sec. 14-4(e), added by Ord. No. 25-O-20 on 2025-01-21: a stay shorter than 30 consecutive days needs the property registered as a rental under 14-4(a) plus an annual short-term rental unit license (a $50.00 per unit application fee and a $100.00 per unit annual fee), a named Waukegan-resident 24-hour emergency contact if the owner lives elsewhere, posted occupancy limits, and remittance of the city's six percent hotel and motel occupancy tax, with a $750.00 fine per violation. There was no cap on short-term rental licenses for the 2025 license year, but 14-4(e)(6) reserves the City Council's right to impose one by later ordinance. Nothing in the code bars an ADU specifically from short-term rental, and nothing in the code addresses selling an ADU separately from the main house.