Chapter 18.19
NONCONFORMING USES, STRUCTURES, AND LOTS Revised 4/24
Sections:
18.19.030 Establishment of lawful nonconforming uses, structures and lots.
18.19.040 Continuation and maintenance of nonconforming structures.
18.19.050 Additions and enlargements to nonconforming structures.
18.19.060 Expansion of nonconforming uses.
18.19.070 Changes and substitutions of nonconforming uses.
18.19.080 Repair and replacement of damaged or destroyed nonconforming buildings. Revised 4/24
18.19.090 Abandonment of nonconforming uses. Revised 4/24
18.19.010 Purpose.
This chapter is intended to permit continuation of uses and continued occupancy and maintenance of structures that were legally established but do not comply with all of the standards and requirements of this title in a manner that does not conflict with the General Plan. To that end, the chapter establishes the circumstances under which a nonconforming use or structure may be continued or changed and provides for the removal of nonconforming uses and structures when their continuation conflicts with the General Plan and public health, safety, and general welfare. (Ord. 1438 § 4 (Exh. A (part)), 2011)
18.19.020 Applicability.
The provisions of this chapter apply to structures, land, and uses that have become nonconforming by adoption of the ordinance codified in this title as well as structures, land, and uses that become nonconforming due to subsequent amendments to its text or to the Zoning Map.
A. Nonconforming structures and uses include:
1. Those made nonconforming by the addition of a standard or requirement previously not required for such use or structure; and
2. Uses and structures reclassified from permitted to being subject to a discretionary permit.
B. Nothing contained in this chapter shall be deemed to require any change in the plans, construction, or designated use of any building or structure for which a building permit has properly been issued, in accordance with the provision of ordinances then in effect and upon which actual construction has been started prior to the effective date of the ordinance codified in this title; provided, that in all such cases, actual construction shall be diligently carried on until completion of the building or structure. (Ord. 1438 § 4 (Exh. A (part)), 2011)
18.19.030 Establishment of lawful nonconforming uses, structures and lots.
Any lawfully established use, structure, or lot that is in existence on the effective date of the ordinance codified in this title or any subsequent amendment but does not comply with all of the standards and requirements of this title shall be considered nonconforming. Nonconforming uses and structures may only be continued subject to the requirements of this chapter.
A. Nonconformities, Generally. A nonconformity may result from any inconsistency with the requirements of this title including, but not limited to, location, density, floor area, height, yard, usable open space, buffering, performance standards, or the lack of an approved use permit or other required authorization. A use or structure shall not be deemed nonconforming solely because it does not conform with the parking and loading space dimension standards, landscape planting area, or screening regulations of the district in which it is located or does not conform to the standards for the following building features: garage door location; garage door width; cornices, eaves, and other ornamental features that exceed maximum projections into required yards; or bay windows, balconies, and terraces above the second floor that exceed maximum projections into required yards. Also see Section 18.20.030(B), Nonconforming Parking or Loading.
B. Nonconforming Lots. Any lot that is smaller than the minimum lot size required by this title or does not meet any of the applicable dimensional requirements shall be considered a lawful nonconforming lot if it is described in the official records on file in the office of the San Mateo County Recorder as a lot of record under one ownership. A nonconforming lot may be used as a building site subject to compliance with all applicable requirements, unless a variance or other modification or exception is approved as provided for in this title.
C. Airport Hazards. No permit shall be granted that would allow the establishment or creation of an airport hazard or permit a nonconforming structure or nonconforming use to be made or become higher or become a greater hazard to air navigation than it was when the applicable regulation was adopted or than it is when the application for a permit is made. (Ord. 1438 § 4 (Exh. A (part)), 2011)
18.19.040 Continuation and maintenance of nonconforming structures.
Lawful nonconforming structures may be continued and maintained in compliance with the requirements of this section unless deemed by the Building Official to be a public nuisance because of health or safety conditions.
A. Right to Continue. Any use or structure that was lawfully established prior to the effective date of the ordinance codified in this title or of any subsequent amendments to its text or to the Zoning Map may only be continued and maintained provided there is no alteration, enlargement, or addition to any building or structure; no increase in occupant load; nor any enlargement of the area, space, or volume occupied by or devoted to such use, except as otherwise provided in this chapter. The right to continue a nonconforming use or structure shall attach to the land and shall not be affected by a change in ownership. No substitution, expansion, or other change in use and no alteration or other change in structures is permitted, except as otherwise provided in this chapter.
B. Maintenance and Nonstructural Repairs. Maintenance, nonstructural repairs and nonstructural interior alterations to a nonconforming structure are permitted if the changes and improvements do not enlarge or extend the structure.
C. Structural Repairs. Structural repairs that do not enlarge or extend the structure, including modification or repair of building walls, columns, beams, or girders, may be permitted only when the Building Division determines that such modification or repair is immediately necessary to protect public health and safety, occupants of the nonconforming structure, or occupants of adjacent property, and when the cost of such work does not exceed fifty percent of the appraised value of the nonconforming structure.
D. Metal Structures. Metal structures that do not conform to the Building and Fire Code shall be improved so as to comply with the Building and Fire Code standards or removed. Prior to the issuance of a building permit or zoning clearance for an alteration, change in occupancy, change in ownership or repair of damage by fire or disaster to a nonconforming metal structure, the property owner shall enter into an agreement with the City providing that the structure shall be improved or altered to comply with the City Building and Fire Codes, or shall be removed within fifteen years of the agreement date. This provision shall be imposed:
1. When a change in occupancy (as defined by the Uniform Building Code) is proposed for more than fifty percent of the gross floor area of the building;
2. When the building or property ownership changes; or
3. When the building is damaged by fire or other disaster to an extent of more than fifty percent of its appraised value. (Ord. 1438 § 4 (Exh. A (part)), 2011)
18.19.050 Additions and enlargements to nonconforming structures.
Nonconforming structures may be enlarged or extended in compliance with all applicable laws subject to the following provisions:
A. Additions Generally. Additions to and/or enlargements of nonconforming structures are allowed, and no use permit is required, if the addition or enlargement complies with all applicable laws and requirements of this Code and if the existing use of the property is conforming.
B. Residential Additions. Additions or enlargements may be made to a building that is designed for and used as a residence without requiring any additional parking space or changes to an existing driveway; provided, that such alterations or enlargements neither trigger the need for additional parking pursuant to Chapter 18.20, Parking and Loading, nor occupy the only portion of a lot that can be used for required parking or access to parking.
C. Accessory Dwelling Units. Notwithstanding the requirements of subsection B of this section, an accessory dwelling unit in compliance with Section 18.23.210, Accessory dwelling units/junior accessory dwelling units, may be developed on a lot that contains a single-unit dwelling that is nonconforming with respect to development standards.
D. Effect of Nonconforming Setbacks. For the purpose of additions in any residential district, maintaining an existing nonconforming setback shall not be considered an increase in the discrepancy; provided, that:
1. Such maintenance is consistent with the provisions under Sections 18.19.040(B) and (C);
2. In no case shall any existing setback of less than three (3) feet be considered legal for the purposes of this chapter; and
3. Any residential additions shall conform to the setbacks in effect at the time the application for the addition is submitted.
E. Effect of Excessive Lot Coverage. Additions to or enlargements of nonconforming structures that exceed the maximum allowable lot coverage require approval of a variance pursuant to the provisions of Chapter 18.32, Variances, if the addition or enlargement would increase the lot coverage. (Ord. 1566 (Exh. B (part)), 2020: Ord. 1480 (Exh. C (part)), 2015: Ord. 1438 § 4 (Exh. A (part)), 2011)
18.19.060 Expansion of nonconforming uses.
No lawful nonconforming use may be expanded without the approval of a use permit, subject to the following requirements:
A. Within a Conforming Structure. A nonconforming use occupying a portion of a structure that conforms to this title may expand the portion that it occupies with Zoning Administrator approval of a minor use permit in accord with Chapter 18.30, Use Permits.
B. Expansion within a Structure That Does Not Conform to This Title. A nonconforming use in a structure that does not conform to the requirements of this title but does conform to the requirements of the Building Code may expand its occupancy and building floor area subject to Zoning Administrator approval of a minor use permit in accord with Chapter 18.30, Use Permits; provided, however, that the expansion meets the requirements of this title.
C. Expansion within a Structure That Does Not Conform to the Building Code. Any nonconforming use in a structure that does not conform to the Building Code may not expand the area it occupies until and unless the structure is brought into conformance with all applicable Building Code requirements. (Ord. 1438 § 4 (Exh. A (part)), 2011)
18.19.070 Changes and substitutions of nonconforming uses.
No lawful nonconforming use shall be changed to a different use type or subclassification without the approval of a use permit unless the new use is permitted by right in the zoning district. This requirement does not apply to a change of ownership, tenancy, or management where the new use is of the same use type and use classification, if applicable, as the previous use, as defined in Chapter 18.40, Use Classifications, and the use is not expanded or intensified.
A. Change from Nonconforming to Permitted Use. Any nonconforming use may be changed to a use that is allowed by right in the district in which it is located and complies with all applicable standards for such use.
B. Absence of Permit. Any use that is nonconforming solely by reason of the absence of a use permit may be changed to a conforming use by obtaining a minor use permit pursuant to the requirements in Chapter 18.30, Use Permits.
C. Substitutions. The Zoning Administrator may allow substitution of a nonconforming use with another nonconforming use, subject to approval of a minor use permit. In addition to any other findings required by this title, the Administrator must finding that:
1. The existing nonconforming use was legally established;
2. The proposed new use would not preclude or interfere with implementation of the General Plan or any applicable adopted specific, area, or community plan;
3. The proposed new use will be no less compatible with the purposes of the district and surrounding uses that comply with the requirements of this title than the nonconforming use it replaces;
4. The proposed new use will not be detrimental to the health, safety, peace, comfort, or general welfare of persons residing or working in the surrounding area or be detrimental or injurious to property and improvements of adjacent lots, the surrounding area, or the neighborhood because of noise, odors, dust, glare, vibrations, or other effects; and
5. The proposed new use will comply with all applicable standards of the district and City-wide standards, there are special circumstances peculiar to the property and its relation to surrounding uses or to the district itself that would justify modification to applicable standards, or the impacts of the new use will be mitigated. (Ord. 1438 § 4 (Exh. A (part)), 2011)
18.19.080 Repair and replacement of damaged or destroyed nonconforming buildings. Revised 4/24
A lawful nonconforming building or structure that is damaged or partially destroyed by fire, explosion, earthquake, or natural disaster which is not caused by an act or deliberate omission of a property owner, their agent, or person acting on their behalf or in concert with, may be restored or rebuilt subject to the following provisions.
A. Restoration When Damage Is Fifty Percent or Less of Value. If the cost of repair or reconstruction does not exceed fifty percent of the appraised value of the building or structure replacement of the damaged portions of the building is allowed by right; provided, that the replaced portions are the same size, extent, and configuration as previously existed. The determination of the appraised value shall be made by a professional appraiser selected by the City, whose fee shall be paid by the building owner.
B. Restoration When Damage Exceeds Fifty Percent of Value. If the cost of repair or reconstruction exceeds fifty percent of the appraised value of the building or structure, as determined pursuant to subsection A of this section, the land and building shall be subject to all of the requirements of this title, except as provided below:
1. Nonresidential Structures. The Planning and Transportation Commission may approve a conditional use permit for the structure to be rebuilt to the same size, extent, and configuration as previously existed. In such cases any expansion or change to the previous use must conform to the requirements of this chapter.
2. Residential Structures. Any nonconforming residential use may be reconstructed, restored, or rebuilt up to the size and number of dwelling units prior to the damage and the nonconforming use, if any, may be resumed subject to a zoning clearance in the case of single-unit dwellings or a conditional use permit approval in the case of other residential uses, unless the Zoning Administrator finds that:
a. The reconstruction, restoration, or rebuilding will be detrimental or injurious to the health, safety, or general welfare of persons residing or working in the neighborhood, or will be detrimental or injurious to property and improvements in the neighborhood; or
b. The existing nonconforming use of the building or structure can be more appropriately moved to a zoning district in which the use is permitted, or that there no longer exists a district in which the existing nonconforming use is permitted.
3. Any reconstruction, restoration, or rebuilding undertaken pursuant to this section shall conform to all applicable Building Code requirements, and a building permit must be obtained within two years after the date of the damage or destruction. (Ord. 1612 § 1 (Exh. A), 2024; Ord. 1438 § 4 (Exh. A (part)), 2011)
18.19.090 Abandonment of nonconforming uses. Revised 4/24
No nonconforming use may be resumed, reestablished, reopened or replaced by any other nonconforming use after it has been abandoned or vacated for a period of six months, except as provided for in this section.
A. Abandonment. The six-month period shall commence when the use ceases and any one of the following occurs:
1. The site is vacated;
2. The business license lapses;
3. Utilities are terminated; or
4. The lease is terminated.
B. Reestablishment. The nonconforming use of a legally established structure may be reestablished if the Planning and Transportation Commission approves a conditional use permit after making all the following findings in addition to any other required findings. As a condition of approving the resumption of such nonconforming use, the Commission may impose a time limit on its duration if necessary in order to make the required findings.
1. The structure cannot be used for any conforming use because of its original design or because of lawful structural changes made for a previous nonconforming use;
2. The structure can be reasonably expected to remain in active use for a period of twenty years without requiring repairs or maintenance in excess of fifty percent of the replacement cost of the structure, as determined by the Building Official, within any five-year period; and
3. The continuation of the use or structure will not be incompatible with or detrimental to surrounding conforming uses. (Ord. 1612 § 1 (Exh. A), 2024; Ord. 1438 § 4 (Exh. A (part)), 2011)
18.19.100 Abatement.
The provisions of this chapter shall not apply to a use or structure that is or becomes a public nuisance. In the event that a legal nonconforming structure or use is found to constitute a public nuisance, appropriate action may be taken by the City pursuant to the municipal code and Section 18.39.020, Enforcement. (Ord. 1438 § 4 (Exh. A (part)), 2011)