ADU Remodel & Renovation in Sacramento: Convert, Upgrade or Legalize

"ADU remodel" covers three very different projects. Some homeowners want to turn a garage or an old workshop into a legal living unit. Some already have an ADU and want to update it. And many Sacramento properties have a unit that was built years ago without a permit. The rules, the permits and the budget are different for each, so it pays to know which one you are dealing with before you call anyone.

1. Converting existing space into an ADU

California treats an ADU built inside existing space more generously than a new build. Under Government Code section 66323, a unit inside the existing walls of a house or an accessory structure (a garage, a workshop, a pool house) must be approved ministerially. That means no public hearing and no discretionary review.

• Setbacks: no setback can be required for existing space that is converted, or for a structure rebuilt in the same place and size. For conversions under section 66323 the side and rear setbacks only need to be "sufficient for fire and safety."
• A little extra room: a conversion of an accessory structure may add up to 150 square feet, but only to provide ingress and egress (an entry, a landing, a stair).
• Parking: when a garage or carport is converted, the city cannot require you to replace those parking spaces.
• Fire sprinklers: they cannot be required in the ADU if the main house does not need them.
• Utilities: a conversion ADU cannot be forced to install a new or separate utility connection or to pay connection or capacity charges (Gov. Code 66311.5).

A garage is the most common starting point in Sacramento because the slab, the roof and most of the walls are already there. The work is usually insulation, a raised or leveled floor, windows that meet egress rules, a kitchen, a bathroom and new electrical. Our garage conversion page walks through the full scope.

2. Renovating an ADU you already have

If the unit is already permitted, updating it works much like any other remodel. The City of Sacramento publishes which work needs a permit:

• Permit required: remodels, garage conversions, water heater replacement, shower and tub enclosure replacement.
• No permit: painting, tile, cabinets and countertops.
• Minor permit by email: non-structural kitchen and bathroom remodels can go through the city's "minor permit" process with no plans. Anything structural (moving a wall, a new window opening, a roof change) needs full plan review.

Common upgrades: a second bedroom carved out of a large living area, a full kitchen in place of a kitchenette, a larger shower, better insulation and windows, and a mini-split instead of a wall heater. If you plan to rent the unit, it is worth doing the permitted work now: a documented ADU is easier to insure, finance and eventually sell with the house.

3. Legalizing an unpermitted ADU

This is where the law changed the most. Before, an unpermitted unit could mean a stop-work order and a demand to tear it out. Since AB 2533 (now Government Code section 66311.7), the picture for units built before January 1, 2020 is different:

• The city cannot deny a permit for such an ADU or JADU because it does not meet current building standards or the local ADU ordinance. The exception is a violation that has to be fixed under the state's substandard-building rules (health and safety items).
• Impact and connection fees generally do not apply to these units, with narrow exceptions.
• The owner can have a licensed contractor do a confidential inspection before applying, so you know what needs fixing before the city is involved. The city may not penalize you for applying, and it must approve the permits needed to correct health and safety items.
• Separately, under SB 13 the owner of a pre-2020 ADU can ask the city to delay enforcement for five years when the correction is not needed for health and safety. Applications for that delay close on January 1, 2030.

The practical order is: confidential inspection, a list of what must be corrected, drawings of the unit as built, the permit application, then the corrections and final inspection.

Which path is yours?

Your situation	Path	Main paperwork
Garage, workshop or basement you want to live in	Conversion ADU	ADU permit, plans
Permitted ADU that feels dated or too small	Renovation	Remodel or minor permit
Unit built without a permit before 2020	Legalization	Inspection, as-built plans, permit
Unit built without a permit after 2020	Case by case	Talk to a contractor first

What drives the cost

We don't publish a single "ADU remodel" price because the range is too wide to be useful. What moves the number: whether plumbing has to reach a new bathroom or kitchen, whether the slab needs work, the size and number of new windows, the electrical panel capacity, and, for legalization, how much of the existing work has to be opened up. A site visit and a few photos usually get you to a realistic estimate within a day.

FAQ

Do I lose my garage parking if I convert it?

You lose the space physically, but the city cannot require you to replace it when the garage becomes an ADU.

Can I convert part of my house instead of the garage?

Yes. A junior ADU (JADU) of up to 500 square feet can be created inside the house. It can have its own bathroom or share one with the main house.

Will legalizing my old unit raise my property tax?

California reassesses only the newly constructed part of a property, not the whole home. How the assessor values a legalized unit depends on the case, so ask the county assessor before you apply.

Sources: California Government Code sections 66311.5, 66311.7, 66314, 66322, 66323 and 66331; Health and Safety Code 17980.12; City of Sacramento Community Development, Required Permits and Minor Permits pages. Checked September 2026. Rules change; confirm with the city before you build.