ADU Rules: Chicago vs Tinley Park

Can I build an ADU on my property in Chicago?

Chicago ADU Ordinance: permanent program effective April 1, 2026 citywide (with aldermanic opt-in for single-family RS zones). Pilot program active in 5 zones since 2021. Coach houses up to 1,200 sq ft.

What are the size limits for an accessory dwelling unit in Chicago?

Program: Permanent ordinance effective April 1, 2026. Coverage: Citywide with aldermanic opt-in for RS zones. Pilot Zones: 5 zones pre-opted-in since 2021. Max Size: 1,200 sq ft or 50% of primary dwelling.

Can I build an ADU on my Tinley Park property?

Generally no. Tinley Park's single-family zoning districts permit only one dwelling unit per lot and there is no specific ADU ordinance. A zoning variance would be required and is rarely granted.

Can I finish my basement as an in-law suite?

You may finish a basement as part of the single-family home including a bedroom and bathroom, but a second kitchen or separate entrance creating an independent unit is not permitted without zoning approval.

My property is listed as two-family — can I rent both units?

If the property was legally established as a two-family before current zoning, it may have legal non-conforming status. Confirm with the Community Development Department before advertising or renting.