Chapter 17.26

NONCONFORMING USES, BUILDINGS, AND STRUCTURES

Sections:

• 17.26.010 Purpose. 17.26.020 Definitions.

• 17.26.030 Continuation and Abandonment of Nonconforming Land Uses.

• 17.26.040 Nonconforming Structures and Buildings Regulations.

The Atherton Municipal Code is current through Ordinance 677, passed February 18, 2026.

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This chapter provides regulations for nonconforming land uses, buildings, and structures that were lawful before the adoption or amendment of this zoning code, but that would be prohibited, regulated, or restricted differently under the current terms of this zoning code or future amendments. (Ord. 582 § 1 (Exh. A), 2009)

Terms that are relevant to this chapter are defined in chapter 17.60, Definitions. (Ord. 582 § 1 (Exh. A), 2009)

A. Continuation of Legal Nonconforming Use. The lawful use of land, structures, or buildings existing at the time of adoption of the ordinance codified in this title may be continued, although such use becomes nonconforming by adoption of the ordinance codified in this title.

• B. Restrictions on Nonconforming Uses. Lawful nonconforming uses shall not be:

  1. Enlarged or increased.

  2. Changed to any other nonconforming use.

  3. Extended to occupy greater land area.

  4. Moved to another portion of the lot.

C. If a nonconforming use of land or a nonconforming use of a conforming structure or building is abandoned for a continuous period of six months or more, rights to legal nonconforming status shall terminate. (Ord. 582 § 1 (Exh. A), 2009)

A. Continuation of Legal Nonconforming Structures and Buildings. Structures and buildings that were legal at the time of their establishment but that no longer conform to the provisions of this title shall be deemed legal nonconforming structures and buildings. As such, they may continue to be legally used.

B. Maintenance and Repair. Legal nonconforming buildings and structures may be maintained and repaired, provided the repairs and alterations will not increase the degree of nonconformity.

C. General Regulations for Modifications and Expansion of Nonconforming Buildings and Structures. Generally, legal nonconforming buildings and structures may only be moved, altered, enlarged, reconstructed, or voluntarily

The Atherton Municipal Code is current through Ordinance 677, passed February 18, 2026.

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removed when the work being completed is in conformance with all current zoning and building regulations. However, under certain circumstances, the town permits the reconstruction, alteration, or addition to legal nonconforming buildings and structures, provided they comply with the following provisions:

1. Any legal nonconforming main building that is damaged or destroyed by fire, explosion, earthquake, or other accidental occurrence may be restored within the building envelope that existed immediately prior to the accidental occurrence; provided, that all such reconstruction must meet current building codes. The burden of proving the extent of the building envelope existing immediately prior to the accidental occurrence shall be upon the party seeking to reconstruct the structure.

2. Alterations or additions to legal nonconforming main buildings may be permitted so long as no more than fifty percent of the existing floor area and no more than fifty percent of nonconforming exterior walls are rebuilt, either as a single project or cumulatively over five years or less. Alterations or additions of more than fifty percent are required to meet current zoning and building code requirements. This subsection does not apply to interior alterations.

3. Alterations or additions to legal nonconforming accessory buildings may be permitted so long as the alteration or addition is made to the conforming portion of the accessory building or is made to the nonconforming portion so as to bring that portion into conformity.

4. Addition of solar facilities to an existing structure or building will not be seen as increasing the nonconforming standards of a structure or building.

• D. Special Provisions for Nonconforming Main Buildings in Residential District R-1A. An addition to a legal nonconforming main building in the R-1A zoning district may:

  1. Maintain the building’s existing setback lines, provided the building does not encroach by more than twenty percent into the current R-1A setbacks; and

  2. Maintain the existing building height, provided no portion of the building is taller than thirty feet.

• E. Special Provisions for Nonconforming Main Buildings in Residential District R-1B.

1. An addition to a legal nonconforming main building in the R-1B zoning district shall be permitted only within the main building area:

   • a. Proposed additions to legal nonconforming main buildings beyond the main building area may be permitted upon issuance of a special structures permit. (Ord. 582 § 1 (Exh. A), 2009)

The Atherton Municipal Code is current through Ordinance 677, passed February 18, 2026.

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