There are established several districts into which the city is divided and which are designated as follows:

Except as provided in this chapter, no land shall be used and no structure shall be erected, used, reconstructed, enlarged, altered or moved except as hereinafter specifically provided and allowed in the districts in which such land and structures are located. Subject to the provisions in Sections 16.08.040 through 16.08.090 and Chapters 16.59 through 16.62 and 16.66 through 16.78, none but the uses specified in this chapter, or uses which in the opinion of the planning commission are similar in nature, will be allowed. Developments in the designated flood hazard area shall be designed consistent with the provisions of Chapter 12.04 and Chapters 15.04 and 15.16 relating to floodplain management.

All regulations in this title pertaining to the districts established in Section 16.08.010, are subject to the general provisions, conditions, and exceptions contained in Sections 16.08.040 through 16.08.090.

If any ambiguity arises concerning the appropriate classification of a particular use within the meaning and intent of this chapter, or with respect to matters of height, area requirements or district boundaries as set forth herein, the planning commission shall ascertain all pertinent facts and by resolution set forth its findings and interpretations and thereafter such interpretations shall prevail, subject to rights of appeal, as set forth in Chapter 16.86.

Subject to obtaining a conditional development permit as provided in this title, any building in the M-2 district may be erected to a height exceeding that specified for such districts; provided:

Subject to obtaining a conditional development permit, cluster housing may be permitted in "R" districts when parcel area is one acre or more.

Residential developments shall be processed ministerially, without discretionary review or hearing, if at least twenty percent (20%) of the units are affordable to extremely low-, very low-, and/or low-income households. Reuse sites are identified by the following San Mateo County assessor's parcel numbers (APN) as of the date of the adoption of the ordinance codified in this chapter: 061412440, 071102130, 061422350, 071288560, and 071333200. All regulations of the underlying zoning district and zoning ordinance shall apply. No part of this section shall be read to oppose or otherwise interfere with state housing law.

Home occupations, as defined in Section 16.04.340, may be permitted in residential districts and in residences within the SP-ECR/D district, provided a permit is obtained from the department of community development. Such permits shall be valid for a period of one (1) year, shall be subject to the conditions contained therein and shall be subject to the payment of a fee, as established by the city council.

Any home occupation permit may be denied or revoked after issuance by order of the director of community development upon a finding that the establishment or continuance of the use or occupation would be detrimental to the health, safety, and general welfare of the persons residing in the neighborhood or would be injurious or detrimental to property in the neighborhood or to the general welfare of the city, or on a finding that the conditions of the home occupation permit were violated. Any revocation of such permit shall be made only after a hearing, held after reasonable notice to the permit holder.

A family day care home, as defined in Section 16.04.165, may be a home occupation and as such is a permitted use in a legal dwelling unit in any residential district.

Areas occupied by debris and refuse, or containers therefor, in all C and M and multiple residential districts shall be within a building or screened from view from any public area or adjacent buildings.

Mechanical equipment, such as air conditioning equipment, ventilation fans, vents, ducting, or similar equipment, may be placed on the roof of a building; provided, that such equipment shall be screened from view as observed at an eye level horizontal to the top of the roof-mounted equipment, except for the SP-ECR/D district which has unique screening requirements, and all sounds emitted by such equipment shall not exceed fifty (50) decibels at a distance of fifty (50) feet from such equipment.

Within residential districts, except for the R-1-U (LM) District, excavating into the required setbacks shall not be permitted unless a use permit for this purpose is obtained from the planning commission in accordance with Chapter 16.82 of this title. Such use permit shall not be required for normal landscaping, tree planting, new utility installation, existing utility maintenance, foundations for accessory buildings, and pools and spa construction. As used in this section, excavating shall mean the act of digging, scooping or removing the earth to a depth greater than one foot (1') below the existing grade.

Opportunity sites identified in Appendix 7-1, Table B of the 2023 to 2031 6th Cycle Housing Element for very low- and low-income households are subject to the following provisions: