Colusa County Zoning Code § 49.07 Maximum floor area

(a)

New Detached ADUs: A newly constructed detached accessory dwelling unit (ADU) shall not exceed one thousand two hundred square feet of habitable space.

(b)

New Attached ADUs: A newly constructed attached ADU shall not exceed fifty percent of the existing residential square footage, except:

• A minimum of eight hundred fifty square feet must be allowed for a studio or one-bedroom ADU.

• A minimum of one thousand square feet must be allowed for ADUs with more than one bedroom.

(c)

Internal Conversion ADUs: An ADU created entirely within an existing single-family dwelling shall not exceed forty-five percent of the existing habitable space, excluding the garage, or one thousand two hundred square feet, whichever is less. However:

○ A minimum of eight hundred fifty square feet must be allowed for a studio or one-bedroom ADU.

○ A minimum of one thousand square feet must be allowed for ADUs with more than one bedroom.

(a)

An ADU created entirely within a detached accessory structure shall not exceed one thousand two hundred square feet.

(b)

Fire Sprinkler Requirement: An automatic fire sprinkler system must be installed in any building that undergoes a substantial remodel, addition, or both, if the total floor area is increased by more than fifty percent.

(Ord. No. 568, 5-20-2025)