What will my ADU really cost?
Build a complete planning budget by separating the dwelling itself from site work, professional services and a reserve. Catalog ranges are starting points, not bids.
Start with the full scope
- Ask for separate lines for design, surveying, engineering, permit preparation, city fees, demolition, excavation, utility connections, foundation, structure, finishes and site restoration.
- Record whether appliances, heating and cooling, laundry, internet, exterior paths, fencing and landscaping are included. A “finished ADU” can mean different things in different proposals.
- Keep land purchase, borrowing costs and any repairs to the main home separate so you can compare like-for-like construction proposals.
Use allowances openly
- An allowance is a budget placeholder for work or selections that have not been fully priced. Record what quantity and specification it covers, and who pays any difference.
- Illustrative arithmetic: a $160,000 construction scope plus $20,000 site allowance, $15,000 professional/permit allowance and a $19,500 reserve totals $214,500 before financing and land. These invented figures explain the calculation; they are not local price evidence.
- Replace each placeholder with a written scope or quote before making a financing decision. Avoid counting site or permit costs twice if they are already in the construction scope.
Understand the schedule behind the price
- Separate investigation and design, permit review, procurement, construction and final inspections. A construction duration is not an application-to-move-in promise.
- Ask what must be completed before the clock starts: permit issuance, selections, utility availability and long-lead material delivery.
- Discuss how site discoveries, owner changes and municipal review comments affect both cost and completion date.
Bring this to your review
- Save a concept and an estimate in My ADU plan. List the three things you most want to preserve if the scope needs to shrink.
- Bring any existing drawings and known utility or access concerns. A partner can identify the next investigation needed to tighten the estimate.
Turn the checklist into a project plan
Record each open question, the person responsible, evidence needed and target date. Confirm requirements with the city and your licensed design/build professionals.
Find your city guide · Prepare a budget · Discuss this checklist at my free review
Planning guidance. Requirements depend on the property, design and adopted local codes; this guide does not certify compliance. How our guidance is prepared