More room for what comes next.

Zoning and setbacks, whether utilities reach the lot, soil and slope, and access for construction. A site review before you commit is worth more than any early design.

It looks at the lot before anything is designed: zoning and setbacks, where utilities are, soil and slope, access for construction, and anything recorded on the property. The result is a short list of conditions to confirm with the city and any specialists.

It depends on the condition of the existing house, what the city allows, and what you need. Comparing both for the same property is the only honest way to decide.

An addition enlarges your existing home and stays part of one dwelling. An attached ADU is a separate unit with its own entrance, kitchen and bathroom, reviewed under ADU rules.

Often yes, with planning around noise, dust, utilities and access. Some stages, such as work on kitchens or main systems, may make it harder.

Work that changes the structure, plumbing, electrical or mechanical systems usually does; purely cosmetic work often does not. Your city decides, so confirm before work starts.

Through a new foundation beside the house, framing that ties into the existing walls and roof, and weatherproofing where old meets new. How the roofs meet and whether the floor levels match are decided early in design.

Yard space, setbacks, existing structures and utility routes usually narrow it down. A garage conversion reuses a structure; a detached unit needs yard space; an attached unit shares a wall with the house.

Yes. You can rent an ADU separately from the house, and the city cannot require you to live on the property; it may prohibit rentals shorter than 30 days. A junior ADU is different: if it shares a bathroom with the house, the owner must live in either the main residence or the junior ADU, and it may only be rented for more than 30 days. Other local rules still apply, so confirm with your city. (California Government Code §66314(d)(1), §66315, §66333(b) and (g))

A small unit inside the house: no larger than 500 square feet of interior living space, contained entirely within a single-family home. It may have its own bathroom or share one with the house. (California Government Code §66313(d))

No. The city cannot require you to replace the parking lost when a garage is converted to an ADU. Your city’s other requirements still apply, so confirm them before you plan. (California Government Code §66314(d)(11))

The permitting agency has 15 business days to tell you whether your application is complete, then 60 days to approve or deny a complete application when a house already exists on the lot. Details and sources on the ADU page

Only a newly built detached ADU needs new solar panels; attached ADUs and garage conversions do not. Details and sources on the ADU page

Not if the ADU is 750 square feet or less (500 for a junior ADU). Other fees, such as permit, school and utility connection fees, can still apply. Details and sources on the ADU page

With the city or county where the property is; each has its own ADU ordinance and submittal process. Details and sources on the ADU page

Not exactly from a web page. For remodels, additions and ADUs, the cost calculator on the homepage shows an early planning range based on published California builder pricing; it is not a quote. Cost depends on the site, the size, the design and finishes, so a realistic number for your project comes after the property has been reviewed and a concept exists.

Size, site conditions, how much of an existing structure changes, and finish level. The scope section on each service page explains each one.

Yes. Plans are reviewed and approved by the city before physical work begins, and inspections happen at stages during construction.

You talk through your goals, the property and your questions. Bringing the preparation checklist from the Resources page makes it more useful.