A common early mistake is choosing the wrong permit office. A mailing address does not always match the city boundary. The lot may be in the City of Los Angeles, another city or unincorporated Los Angeles County. Each office has its own rules and filing steps.
Confirm the permit office before applying a size, setback, parking or plan-review statement to the property.
Property Records and ADU Permit Authority
Collect the facts below.
- street address and assessor parcel number;
- legal owner and parcel description;
- city limits or unincorporated Los Angeles County status;
- zoning and any applicable specific plan;
- lot area and dimensions;
- current permitted dwellings and accessory structures;
- permit history for a garage or addition;
- easements and recorded constraints; and
- survey details where boundaries or grade are uncertain.
An online map is useful for an early check. It is not a property survey or a final zoning choice.
Detached, Attached, Garage Conversion or JADU?
Place the concept in one of the groups below.
- new detached construction;
- attached new construction;
- conversion of part of the main dwelling;
- conversion of an attached or detached garage or accessory structure;
- a JADU within a qualifying single-family structure;
- work on a multifamily property; or
- legalization or completion of an existing unit.
The answer controls which size, unit-count and building rules apply. If the goal is still unclear, describe who will use the unit. Add the room count, privacy needs and budget. Do not choose a project label too early.
ADU Site Layout, Access and Setbacks
Ask the designer for a measured site plan showing lot lines, streets, existing and proposed buildings, access, trees, drainage and utility routes. Include easements and any uncertain boundaries that need a survey.
Measure the narrowest route from the street to the work area. Note gates, overhead lines, walls, pools and places where equipment or materials cannot be stored. Use these details to test the proposed ADU footprint before comparing construction prices.
Ask the actual permit office which drawings and site information it requires for this address and project type.
Hillside, Fire, Historic and Other ADU Site Constraints
Ask the permit office or a qualified designer about each condition below.
- hillside or steep-slope conditions;
- wildfire or fire-access rules;
- coastal-zone review;
- a historic district, HPOZ or designated resource;
- flood, drainage or debris-flow details;
- protected trees or biological constraints;
- methane, liquefaction or other mapped geotechnical conditions;
- private street or limited fire access;
- rent, tenant or replacement-housing rules; or
- a pending subdivision or SB 9/SB 1123 process.
This list helps find questions. A condition shown on a map does not by itself approve or reject an ADU.
Garage and Existing-Structure Checks for an ADU
For a garage or interior conversion, record its legal use and size. Check the slab, frame, roof, moisture, openings, ceiling height and building systems. The quote should say what stays and what must be replaced or upgraded.
The garage conversion guide gives a fuller inspection list. Do not assume that avoiding a new footprint avoids structural, energy or utility work.
ADU Utility Capacity and Connection Planning
Record the current electric service, panel and meter. Add the water, sewer and gas service if gas is planned. Draw the likely routes to the ADU.
LADWP’s meter-spot page explains how it checks the panel location. It says a visit is usually set within 5–15 business days for the service shown on that page. New-build requests go to the Connection Center.
LADWP’s water installation page asks for the address, parcel number, service size and use. LADWP then issues a project Cost Letter. Main-line work and other rules can add cost and time.
Different cities, counties and utility companies use different processes. Use the utilities and site-work guide to make sure this work appears in the plan and price.
Using Pre-Approved ADU Plans on Your Property
If you are considering a pre-approved design, ask the permit office to confirm that the selected plan is accepted for the current code cycle and proposed property. Obtain the allowed options and site-submission requirements before buying design work.
Compare the plan as issued with the changes your site needs: placement, foundation, access, drainage and utility routes. Ask who prepares those details and whether a proposed change requires a different review path. The standard-plan comparison helps compare that work with a custom design.
Possible Results of an ADU Feasibility Review
A useful report should end with one of four conclusions.
| Conclusion | Meaning | Next step |
|---|---|---|
| The idea may work | no known issue rules it out, subject to permit-office review | develop a design and utility plan for the property |
| The idea may work with changes | the type, size, location or systems should change | price only the revised plan |
| Important facts are missing | boundaries, records, structure or utilities remain unclear | obtain the missing records or inspection |
| The idea is a poor fit | limits or cost make this option unattractive | test a conversion, smaller unit or no-build option |
Avoid a percentage “buildable score” that hides which facts remain unverified.
What Does an ADU Feasibility Review Cost?
There is no single Los Angeles price because the work can differ. Check what each early-review quote includes. Look for record research, field measurements, a survey and a zoning check. It should also cover unit placement, utilities, written risks, agency contact and clear next steps.
Ask whether the fee is credited toward later design, whether the company owns the work product and which conditions require specialists.
Information for Comparing ADU Construction Bids
At a minimum, each bidder should get the same site facts, design and finish level. Give them the same utility assumptions, site work and exclusions too. If major questions remain, ask for an early budget with clear allowances. A fixed price is not useful until the facts support it.
The cost guide and builder comparison provide the shared fields.
Frequently asked questions
Can the City tell me exactly what an ADU will cost?
No. City and utility sources confirm rules and charges within their control. Construction price depends on the design, site, company, materials, allowances and discovered conditions.
Does state law mean every parcel can take the same ADU?
Use the proposed unit type and address to ask the permit office which approval path applies. Have the designer check the site, utilities and any relevant overlays before relying on a general summary of State law.
Do I need a survey?
Not every early screen requires a new survey. If property lines, easements, grade or the available envelope are uncertain, a survey may be necessary before relying on setbacks or final placement.
Can a website form confirm that an ADU will work?
No. A form can collect the starting facts and route the inquiry. Checking the property requires current records and review by qualified people.