Accessory Structures in Arlington Heights, IL: What Residents Actually Need to Know

If you live in Arlington Heights or are thinking about moving there, accessory structures are one of those things you probably won't think about until they affect you directly. Arlington Heights has 5 specific rules on the books covering different aspects of accessory structures, and some of them might surprise you.

Tiny Homes

Arlington Heights does not permit tiny homes as independent dwelling units on residential lots. The Village zoning ordinance establishes minimum dwelling size requirements and does not recognize tiny homes on wheels as permanent structures. Tiny homes on foundations would need to meet all building code and zoning requirements including minimum square footage.

Key details: Tiny Homes Permitted: Not as independent dwellings. Minimum Home Size: Generally 1,000+ sq ft. On Wheels: Classified as RV, not dwelling. ADU Use: Not permitted. Pilot Programs: None adopted.

Using a tiny home on wheels as a dwelling is a zoning violation subject to fines of $100-$750 per day. The Village may order removal of the unit. Building an undersized dwelling without meeting minimum square footage requirements is a building code violation. Contact Community Development at (847) 368-5100.

This is one of the stricter rules in Arlington Heights's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.

Carport Rules

Carports in Arlington Heights are treated as accessory structures and require a building permit. They must meet setback requirements and height limits. Carports do not satisfy the Village's requirement for enclosed parking spaces, so they cannot replace a garage for zoning compliance purposes.

Key details: Permit Required: Yes. Setback: 3 feet from property lines. Front Yard: Not permitted. Counts as Enclosed Parking: No. Temporary Canopies: Generally not allowed permanently.

Building a carport without a permit may result in fines and an order to remove the structure or obtain a retroactive permit. Temporary car canopies left in place may be cited as zoning violations. Carports that do not meet setback requirements must be relocated or removed. Contact Community Development at (847) 368-5100.

ADU Rules

Arlington Heights does not currently permit accessory dwelling units (ADUs) as a by-right use in most residential zoning districts. The Village's zoning ordinance generally limits residential lots to one principal dwelling. Coach houses or secondary units may be possible through a special use permit or planned development process, but approval is not guaranteed and requires public hearings.

Key details: ADUs Permitted: Not by right in most zones. Special Use Permit: Required for secondary units. State ADU Mandate: Illinois has none. Accessory Living Space: Allowed without separate kitchen/entrance. Public Hearing: Required for zoning relief.

Creating an unauthorized dwelling unit is a zoning violation subject to fines of $100-$750 per day. The Village may require removal of the unauthorized unit and restoration to its original configuration. Renting an unauthorized dwelling unit compounds the violation. Contact Community Development at (847) 368-5100.

This is not one of those rules that cities tend to ignore. Arlington Heights actively enforces its adu rules requirements.

Shed Rules

Arlington Heights allows accessory storage sheds on residential property subject to size limits, setback requirements, and permit thresholds. Sheds under 100 square feet generally do not require a building permit but must still comply with setback and height restrictions. Larger sheds require a permit. Sheds may not be used as habitable space.

Key details: Permit Threshold: Required if 100+ sq ft. Setback: 3 feet from property lines. Maximum Height: 15 feet. Front Yard: Not permitted. Habitable Use: Prohibited.

Building a shed over 100 square feet without a permit may result in fines and an order to remove the structure or obtain a retroactive permit with double fees. Sheds in violation of setback requirements may need to be relocated. Deteriorated sheds may be cited under property maintenance codes. Contact Community Development at (847) 368-5100.

Garage Conversions

Converting a garage to living space in Arlington Heights is heavily restricted. The Village zoning ordinance requires residential properties to maintain a minimum number of enclosed parking spaces. Converting a garage to habitable space typically requires providing replacement off-street parking and obtaining building permits for the conversion.

Key details: Replacement Parking: Must provide enclosed off-street parking. Minimum Parking: 2 enclosed spaces required. Permit Required: Yes, building permit. ADU Restriction: Cannot create separate dwelling. Building Code: Must meet habitable space standards.

Unpermitted garage conversions are subject to fines and an order to restore the garage to its original use or provide compliant replacement parking. Fines may range from $100 to $750 per day of violation. The Village may deny future permits until the violation is resolved. Contact Community Development at (847) 368-5100.

Compared to other cities, Arlington Heights takes a harder line on garage conversions. The enforcement and penalty structure reflects that.

The Bottom Line

Arlington Heights is tougher than many cities when it comes to accessory structures. Out of the 5 rules covered here, 3 are rated strict. If you are a homeowner, renter, or business owner in Arlington Heights, take the time to understand these requirements before they become a problem. Most violations come with fines, and some repeat violations can escalate.

This guide is based on Arlington Heights's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.