23.324.030 Nonconforming Lots.
A. Lawful Nonconforming Lots. A lot with an area less than the minimum lot size required by the Zoning Ordinance is considered a lawful nonconforming lot if the lot is:
1. Described in the official records on file in the office of the County Recorder of Alameda County or Contra Costa County as a lot of record under one ownership before November 30, 1950;
2. Shown as a lot on any recorded subdivision map, filed before November 30, 1950; or
3. In the Environmental Safety Residential (ES-R) district and described in the official records on file in the office of the County Recorder of Alameda County as either:
(a) A lot of record under one ownership; or
(b) A lot on any recorded subdivision map filed before February 13, 1975.
B. Requirements.
1. A lawful nonconforming lot may be used as building site subject to all other requirements of the Zoning Ordinance, except as provided in Paragraph (2) below.
2. If the total area of all contiguous vacant lots fronting on the same street and under the same ownership on or after September 1, 1958 is less than that required for one lot under the Zoning Ordinance, such lawful nonconforming lots may be used as only one building site. (Ord. 7787-NS § 2 (Exh. A), 2021)