Editorial & Source Policy

ADU Project Planner is built to help U.S. homeowners organize accessory dwelling unit decisions with practical, transparent guidance. Because ADU requirements vary by jurisdiction and change over time, regulatory information should be traceable to authoritative sources and clearly scoped to the place and date reviewed.

How we research ADU rules

• Prefer primary sources such as state statutes, state housing agencies, municipal codes, planning departments, permit departments, and official guidance.
• Identify the jurisdiction being discussed rather than presenting local rules as universal.
• Record or display review dates on location-specific regulatory guides where practical.
• Separate verified requirements from planning assumptions, estimates, examples, and general guidance.
• Update material when authoritative requirements change or when a guide is substantially revised.

Costs, calculators, and estimates

Cost ranges and planning-tool outputs are educational estimates, not contractor bids, appraisals, engineering opinions, lending offers, or guarantees. Assumptions should be visible so homeowners can understand what drives an estimate and replace general inputs with local information.

Professional and local verification

Property conditions, title issues, utilities, fire access, engineering, taxes, financing, building codes, and permitting can require qualified local professionals or agency review. ADU Project Planner does not replace those determinations. Before making a major financial or construction commitment, verify the requirements that apply to the specific property and jurisdiction.

Corrections

If you identify an outdated rule, broken official-source link, or factual error, contact us with the page and supporting source so it can be reviewed.