ADU Builder in Moraga, CA
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Moraga's New ADU Ordinance
Moraga updated its ADU rules in July 2026, effective August 7, 2026 (Moraga Municipal Code Chapter 8.124). The Town now sorts ADUs into review tracks, and the track decides how fast and simple your approval is.
- Streamlined: a detached ADU up to 800 sq ft, conversions of existing space, and junior ADUs. No parking required.
- Standard: ADUs from 150 to 1,200 sq ft. An attached ADU is limited to 50% of the main home, but never below 800 sq ft. One parking space, with exemptions.
- Everything else: a discretionary Conditional Use Permit.
Detached ADUs can be 16 feet tall, or 18 feet within half a mile of transit plus 2 feet for a matching roof pitch. Attached ADUs can reach 25 feet or the zone limit, two stories maximum. Side and rear setbacks are 4 feet. The Town decides within 60 days of a complete application.
ADU Construction
Moraga's Hillside Standards for ADUs
Moraga is a valley ringed by hills, and the ADU standards reflect that. A ministerial ADU does not need a Hillside Development Permit, but it must stay within local design limits:
- Retaining walls up to 3 feet
- Average slope of the ADU area up to 20%
- Up to 200 cubic yards of cut and fill
- Native trees removed must be replaced one for one
- Materials matching the main home and downward-facing lighting
There is no owner-occupancy requirement for an ADU, rentals must be longer than 30 days, and an ADU cannot trigger fire sprinklers in the main home. Converted garage parking does not have to be replaced.
How a Moraga ADU Gets Approved
- HOA approval first, if you live in Moraga Country Club or Sanders Ranch.
- Town Planning review under the ADU ordinance.
- MOFD plan review.
- County plan check and building permit through ePermits.
- County inspections and final.
329 Rheem Boulevard, Moraga, CA 94556
Town Hall (925) 888-7050 · Planning (925) 888-7040
Planning counter: weekdays 9 to noon and 1 to 5, closed alternating Fridays.
Moraga uses the County Department of Conservation and Development for plan review and inspections. Upload the Town-approved plans to the County ePermits Center. County offices: 30 Muir Road, Martinez · (925) 655-2700. Inspections: ePermits or (925) 646-4108.
Fire district: the Moraga-Orinda Fire District, 1280 Moraga Way, reviews plans for all home changes, including interior remodels.
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Moraga ADU FAQ
How big can an ADU be in Moraga?
A streamlined detached ADU is up to 800 sq ft. A standard ADU can be 150 to 1,200 sq ft, and an attached one is limited to 50% of the home but never below 800 sq ft. A junior ADU is up to 500 sq ft.
Do I need HOA approval for an ADU in Moraga?
In Moraga Country Club and Sanders Ranch, HOA approval comes before the Town reviews the project.
Does a Moraga ADU need a hillside permit?
A ministerial ADU does not, as long as it stays within the Town’s limits on slope, grading and retaining walls.
Who issues the building permit?
Contra Costa County, after Town Planning and MOFD review.