Campbell has a new Inclusionary Housing Ordinance covering ADUs.  See Chapter 21.23 Accessory Dwelling Units”

Allowable ADU sizes are:

Lot Area 10,000-10,999 sq.ft.  ADU can be up to 700 sq.ft.

Lot Area 11,000-11,999 sq.ft.  ADU can be up to 800 sq.ft.

Lot Area 12,000-12,999 sq.ft.  ADU can be up to 900 sq.ft.

Lot Area 13,000-13,999 sq.ft. ADU can be up to 1,000 sq.ft.

Lot Area 14,000-14,999 sq.ft.  ADU can be up to 1,1000 sq.ft.

Lot Area 15,000 sq.ft or greater,  ADU can be up to 1,200 sq.ft.

21.23.050 – General Requirements and Restrictions.

A.  Rentals. No more than one dwelling unit on the parcel, either the accessory dwelling unit or the primary dwelling unit, shall be leased or otherwise rented. Leases for durations of less than thirty days, including short-term rentals (as defined by the California Government Code) are prohibited. The community development director shall require recordation of a deed restriction documenting these restrictions.

B.  Subdivision and sales. No subdivision of land or air rights shall be allowed, including creation of a stock cooperative or similar common interest ownership arrangement.

C. Park impact fee. A fee in-lieu of parkland dedication land shall be paid in compliance withChapter 13.08 (Park Impact Fees).

D. Building code. Accessory dwelling units shall comply with all applicable Building and Fire Codes as appropriate, except that the Building Official shall not require installation of fire sprinklers for an interior accessory dwelling unit if they would otherwise not be required for the primary dwelling unit, except if the creation of the accessory dwelling unit would result in creation of a “new dwelling using portions of the original structure” pursuant to Chapter 18.32(Determination of scope of work).

E. Utilities. The Building Official shall coordinate with local utility agencies to ensure that accessory dwelling units are not considered new residential uses for the purpose of calculating local agency connection fees or capacity charges for utilities, including water and sewer services.

Please read the full Ordinance for complete information.