An ADU plan before purchase: verify feasibility, not just available space
Check accessory dwelling plans against parcel rules, permits, utilities, project scope and realistic rental assumptions.
What matters before you decide
A large yard or an existing garage does not establish that an accessory dwelling unit can be built or legally rented. Confirm the rules for the exact parcel and the intended unit with the local planning and building departments. A standard plan still needs the approvals and site checks applicable to the property.
- Confirm parcel jurisdiction and intended unit type.
- Obtain local written feasibility guidance.
- Match existing units to permits and final inspections.
Define the parcel and proposed use
Start with the parcel number, jurisdiction and intended arrangement: conversion, attached addition or detached unit. Ask about allowed size, location, setbacks, access and any limits on rental use. Identify existing easements and whether the site has drainage, fire access or other constraints. Save dated written guidance from the correct authority. A rule in another California city—or in another state—is not evidence for this address.
Separate an existing room from an approved dwelling
For a marketed garage apartment, request permit history, approved plans, inspection sign-offs and the occupancy document required locally. Compare the records with the actual layout and utility arrangements. Do not infer legal dwelling status from a bathroom, separate entrance, tax record or listing description alone. If records are incomplete, ask the authority what would be needed to establish or legalize the use before putting its rent in your financing plan.
Build a full project and operating budget
Price design, survey, permits, construction, utility connections, site work, financing and a reserve for unresolved conditions. Ask which costs are excluded from a standard-plan or modular-unit advertisement. Model rental income after vacancy, management, maintenance, insurance and applicable fees; avoid counting revenue before completion and lawful occupancy. The Los Angeles LADBS standard-plan checklist linked below is a local example of a submittal process, not a national ADU approval or a statement that your parcel qualifies.
Decision checklist
- Confirm parcel jurisdiction and intended unit type.
- Obtain local written feasibility guidance.
- Match existing units to permits and final inspections.
- Include utilities, site work and delayed rental income.
Frequently asked questions
01Does a preapproved plan approve my property?
No. Confirm site-specific requirements and the actual permit process with the local authority.
02Can I use the Los Angeles checklist nationwide?
It illustrates the kinds of documents a jurisdiction may request. It does not establish another jurisdiction’s rules or authorize construction.
Primary sources and further reading
Always verify the date, scope and local application before using a source for a specific decision.
Independent educational information. Not legal, tax, lending, or investment advice. Verify local rules and consult licensed professionals before making a real estate decision.
Renovation permits and contractor records: verify the remodel
Reconcile advertised improvements with permits, plans, inspections, invoices and visible work, then price unresolved code, safety, insurance and resale consequences.
Read the file
Boundaries and easements: reconcile records with the site
Read the legal description, title exceptions and available survey together before assuming a fence, map or driveway defines property rights.
Read the file
Rental repairs or improvements: organize the tax evidence
Distinguish maintenance records, improvement projects, rental use and placed-in-service dates before preparing tax deductions.
Read the file