Building an ADU in Dane County is a sequential process with real dependencies at each stage. Getting through it cleanly requires preparation — not just knowing what to expect, but knowing what you need to verify, decide, and document before work begins at each phase. This checklist covers it in order.
Before You Talk to Anyone
Before design begins, before a contractor is hired, there are baseline facts to confirm about your specific property. Skipping this step is where most project problems originate.
Confirm your zoning district. Your parcel’s zoning determines what ADU types are permitted, size limits, and setback requirements. In Madison, log into the city’s Parcel Information page. In other municipalities, check with the planning department or use Dane County’s parcel viewer.
Measure your usable backyard. ADUs must meet setback requirements from all lot lines and from the primary structure. In most Madison residential zones, setbacks are 5 feet rear and 3 feet side. Other municipalities differ. Know your dimensions before you imagine where the ADU goes.
Identify underground utilities. Call 811 before any site work. Utility lines — sewer laterals, gas, electric, cable — are often buried where you want to build. Knowing this early affects site selection.
Look for deed restrictions or HOA covenants. Pull your recorded documents from the Dane County Register of Deeds. Some older subdivisions have covenants that restrict ADUs or rental use, separate from zoning.
Assess tree locations. In Madison, trees over 5 inches DBH require review if removal is associated with a development permit. Know your trees before you commit to a footprint.
Design Phase Checklist
Once feasibility is confirmed, design can begin. Before you lock in a layout:
Decide on utilities approach. Will you share electric, water, and sewer connections with the primary residence, or run separate meters? This decision affects cost, site plan design, and how you price any future rental. Decide before design finalizes.
Confirm intended use. Long-term rental, aging family member, short-term rental, home office — the intended use affects layout, bedroom count, bathroom placement, and what amenities make sense. Be specific with your designer.
Set a realistic budget. Include the ADU build cost, impact fees (typically $2,000–$5,000 in Madison), utility connections if separate, landscaping and grading, and any contingency. A 10% contingency is standard.
Identify your financing path. HELOC, cash-out refinance, construction loan, or cash? Your lender may need to be engaged before or during design to confirm loan parameters affect the project scope.
Pre-Permit Submission Checklist
In Madison and most Dane County municipalities, a complete permit submission prevents delays. Missing documents restart the clock. Before submitting:
Site plan complete: Shows all structures, setbacks, impervious surface calculations, utility connection points, grading, and drainage direction.
Architectural drawings complete: Floor plans, elevations, sections, and window/door schedule.
Energy compliance documentation: Wisconsin energy code requires a compliance path showing R-values, window U-factors, and air sealing approach.
Structural calculations (if required): Non-standard foundations or structural spans may require stamped engineering.
Verify municipality-specific requirements: Some municipalities require a pre-application meeting. Madison requires a two-phase process (site plan then building permit). Confirm your municipality’s specific sequence before submitting anything.
During Construction Checklist
Required inspections: Foundation before pour, framing before insulation, rough mechanical (plumbing, electric, HVAC) before drywall, and final inspection for CO. Know these milestones and schedule them proactively — inspection delays are a common timeline risk.
Change orders in writing: Any scope change after contract signing should be documented in a written change order before work proceeds. Verbal agreements create disputes at billing time.
Utility account setup: If doing separate metering, contact MGE or Madison Water during construction to establish service in advance of CO. Utility connection wait times in Madison have run weeks to months — don’t wait until the building is done.
At Certificate of Occupancy
Confirm ADU address is registered: Your ADU should have had a 911 address assigned during site plan review. Verify the address is in the city’s system before a tenant moves in.
Update your insurance: Notify your insurer of the completed ADU before it’s occupied. If you’re renting, confirm you have a landlord policy in place.
Review your lease structure: If renting, prepare a lease that addresses: rent amount, utility allocation, parking, snow removal responsibility, entry notice requirements under Wisconsin law, and the ADU’s official address.
We manage this entire sequence for every project we build in Dane County — from feasibility through CO. If you’re at the beginning of this process and want a direct assessment of your property, start with a free feasibility check.
