§145.1803 Local Additions and Modifications to Section 1803 “Geotechnical Investigations” of the California Building Code
(a) Section 1803.2 is adopted with additions and modifications under Sections 145.0105 and 145.0106 of the Land Development Code.
(1) 1803.2.1. A geotechnical investigation shall be conducted when required by Section 1803.2 of the California Building Code, and Section 145.1803(d) of the Land Development Code, or the Building Official for all new structures, additions to existing structures not exempted by Land Development Code Section 145.1803(b), or whenever the occupancy classification of a building changes to a higher Risk Category under Table 1604.5 of the California Building Code as a result of the proposed work.
(2) 1803.2.2. A geotechnical investigation report shall be submitted to the Building Official unless specifically exempted by one of the waivers in Section 145.1803(b) of the Land Development Code. The report shall contain appropriate recommendations for mitigation of the hazards or conditions identified in accordance with Table 145.1803 of the Land Development Code and Section 1803.5 of the California Building Code, respectively. These recommendations shall be incorporated into the design of the project before issuance of a Building Permit. No Building Permit shall be issued for construction where the geotechnical investigation report establishes that construction of buildings or structures would be unsafe because of the geologic hazards. Issuance of a Building Permit does not constitute a representation by the City that the site does not contain geological hazards or that construction is safe.
(3) 1803.2.3. The Building Official may require that a “NOTICE OF GEOLOGIC AND GEOTECHNICAL CONDITIONS” be executed by the record owner as a condition to the issuance of a Building Permit for any structure to be located over a suspected fault or other geologic hazard. A “NOTICE OF GEOLOGIC AND GEOTECHNICAL CONDITIONS” may also be required when a geologic investigation is not provided or when a geologic investigation cannot conclusively establish that buildings or structures located on the site would either be safe or unsafe. The form of the “NOTICE OF GEOLOGIC AND GEOTECHNICAL CONDITIONS” shall be as provided by the Building Official. When required by the Building Official, the “NOTICE OF GEOLOGIC AND GEOTECHNICAL CONDITIONS” shall be executed by the record owner and recorded with the San Diego County Recorder, and filed with the City of San Diego.
(b) Section 1803.2 is modified and exceptions are added under Sections 145.0105 and 145.0106 of the San Diego Municipal Code.
(1) The Building Official may waive the requirement for a geotechnical investigation where satisfactory data from adjacent areas is available that demonstrates an investigation is not necessary for any of the conditions in California Building Code Sections 1803.5.1 through 1803.5.6 and Sections 1803.5.10 and 1803.5.11.
(2) The Building Official may waive the requirement for a geotechnical investigation for additions and alterations to existing residential and non-residential buildings when all of the following conditions are met:
(A) The site is not located within Geologic Hazard Category 21, as specified in Table 145.1803 of the Land Development Code;
(B) For non-residential buildings, the site is not located within Geologic Hazard Categories 11, 12, 13, or 31 and the existing building’s foundation has not been designed for any earthquake induced ground failure;
(C) The total value of the work is less than 50 percent of the replacement value of the existing building; and
(D) The added gross floor area is less than 50 percent of the gross floor area of the existing building.
(3) The Building Official may waive the requirement for a geotechnical investigation for residential buildings not located within the Alquist-Priolo Earthquake Fault Zone (Geologic Hazard Category 11), Geologic Hazard Categories 21 or 31, where all the following conditions are met:
(A) The dwelling complies with the California Residential or Building Code and is classified as a Group R-3 occupancy;
(B) The dwelling is not more than three stories in height, or not more than two stories in height plus one story below grade plane story (basement); and
(C) The dwelling is not a part of a development with four or more dwellings.
(4) The Building Official may waive the requirement for a geotechnical investigation for remodels and non-structural tenant improvements to existing structures where there is no increase in the Risk Category.
(5) The Building Official may waive the requirement for a geotechnical investigation for structures assigned to occupancy Group U, including swimming pools and spas with a depth of less than six feet, and decks or any other structure of a similar nature.
(6) The Building Official may waive the requirement for a geotechnical investigation for non-residential buildings and structures used for human occupancy and located within the Alquist-Priolo Earthquake Fault Zone when specifically exempted in accordance with Section 2621.7 of the California Public Resource Code.
(c) Section 1803.5 is modified pursuant to Section 145.0106 of the San Diego Municipal Code. 1803.5 (Investigated conditions) Geotechnical investigations shall be conducted as indicated in California Building Code Sections 1803.5.1 through 1803.5.12.
(d) Section 1803.5.11 is modified by adding Subsections 1803.5.11.1 and 1803.5.11.2 pursuant to Section 145.0106 of the San Diego Municipal Code.
(1) 1803.5.11.1. A geotechnical investigation report shall be submitted pursuant to San Diego Municipal Code Sections 145.1803(d), 145.1803(f) and Table 145.1803 unless exempted pursuant to San Diego Municipal Code Section 145.1803(b).
(2) 1803.5.11.2. For structures regulated by the California Residential Code, Section 145.1803(d) shall apply.
(e) Section 1803.5.13 is adopted by reference with modifications pursuant to Section 145.0105 of the Land Development Code: 1803.5.13. Local Geologic Hazards. A geotechnical investigation report shall be submitted when required by Section 145.1803 and Table 145.1803. Notwithstanding Table 145.1803, the Building Official may require a geotechnical investigation report for any site if the Building Official has reason to believe that a geologic hazard may exist at the site based on data not mapped on the City of San Diego Seismic Safety Study maps.
(f) The Geologic Hazard Category and the Building, Structure and Facility Class must be determined as follows when using Table 145.1803 to determine whether a geotechnical investigation report is required due to local geological hazards within the City of San Diego:
(1) The Hazard Category describes the geologic feature or condition suspected at the site. The Hazard Category is determined by reference to the current City of San Diego Seismic Safety Study maps.
(2) City staff shall assign one of four Building, Structure and Facility classes to each building, structure, or facility based on their use, type of occupancy, number of occupants, and whether hazardous materials are being used or stored in the building, structure, or facility to determine whether a Geotechnical Investigation Report is required.
(A) Class A includes the following:
(i) Buildings or structures classified as Essential Facilities in Risk Category IV as defined in Table 1604.5 of the California Building Code.
(ii) Any building, structure, or facility where significant generation or storage of toxic, hazardous, or flammable materials will occur.
(B) Class B includes the following developments, occupancy groups, and structures provided they are not included in Class A:
(i) All new structures requiring deep foundations, such as piers or pilings.
(ii) All structures over three stories in height.
(iii) All structures containing the following occupancies pursuant to the California Building Code, Chapter 3:
a. Group A, Divisions 1, 2, 3 and 4;
b. Group E, buildings and other structures containing elementary school, secondary school or day care facilities with an occupant load greater than 250;
c. Group H, Divisions 1, 2, and 3; and
d. Group I, Divisions 2 and 3.
(iv) All structures with an occupant load of more than 300 occupants as determined by Table 1004.1.2 of the California Building Code and structures used for public assembly assigned to Risk Category III in Table 1604.5 of the California Building Code.
(v) Tanks, bins, hoppers, silos, and other storage structures with more than 20,000-gallon capacity intended to store toxic, hazardous, or flammable contents that are not associated with a building, structure, or facility in Class A.
(vi) Tanks, bins, hoppers, silos, and other storage structures over 35 feet high.
(vii) Towers over 35 feet high.
(viii) Retaining walls over the heights listed in the following Subsections a. and b. with the height measured from the top of the footing to the top of the wall:
a. Retaining walls over 12 feet in height; and
b. Retaining walls over 6 feet in height supporting a surcharge or retaining toxic, hazardous, or flammable contents.
(C) Class C includes the following occupancy groups and structures provided they are not included in Classes A or B:
(i) All structures containing the following occupancies pursuant to the California Building Code, Chapter 3:
a. Group A, Divisions 2, 3 and 5 with rooms having less than 300 occupants;
b. Group B;
c. Group E, buildings and other structures containing elementary school, secondary school or day care facilities with an occupant load less than 250;
d. Group F, Divisions 1 and 2;
e. Group H, Divisions 4 and 5;
f. Group I, Division 1;
g. Group M;
h. Group R, Divisions 1and 2; and
i. Group S, Division 1.
(ii) Retaining walls over the heights listed in the following Subsections a. and b. with the height measured from the top of the footing to the top of the wall:
a. Retaining walls over 6 feet in height; and
b. Retaining walls of 6 feet or less supporting a surcharge or retaining toxic, hazardous, or flammable contents.
(iii) Tanks, bins, hoppers, silos, and other storage structures intended to store toxic, hazardous, or flammable contents;
(iv) Tanks, bins, hoppers, silos, and other storage structures over 20 feet high; and
(v) Towers over 20 feet high.
(D) Class D includes the following occupancy groups and structures provided they are not included in Classes A, B, or C: All structures containing the following occupancies pursuant to the California Building Code, Chapter 3: Group R, Divisions 3 and 4 and buildings regulated by the California Residential Code.
(g) Section 1803.6 is adopted with modifications and additions pursuant to Sections 145.0105 and 145.0106 of the Land Development Code: 1803.6.1. Geotechnical investigations reports prepared pursuant to Section 1803.6 of the California Building Code and Section 145.1803(e) of the Land Development Code shall be required for sites where geologic hazards may exist as determined by the Building Official prior to obtaining a Building Permit. The report shall include all requirements as established by the Building Official. All reports shall be prepared in accordance with the most recent edition of the City of San Diego “Guidelines for Geotechnical Reports,” which is available through the City of San Diego Official Website. These minimum requirements shall be augmented by geologic evaluations pertinent to the type of proposed project and anticipated method of construction, which should be described in the report. For buildings located in both a fault zone and a hazard category zone, the most restrictive requirement shall govern.
(1) Table 145.1803 Required Geotechnical Investigation
Type of Hazard | Geologic Hazard Category | Building, Structure, and Facility Class
Fault Zones/Ground Rupture | 11, 12, 13 | A, B, C, D
Landslides/Potential Slope Instability | 21, 22 | A, B, C, D
23, 24, 25, 26, 27 | A, B, C
Liquefaction/Potential Ground Failure | 31, 32 | A, B, C, D
Coastal Bluff Stability | 41, 42, 43 | A, B, C, D
44, 45, 46, 47, 48 | A, B
All Other Terrain | 54 | A, B, C
52, 53 | A, B
51, 55 | A
Footnotes:
(1) See Land Development Code Section 145.1803 (f) and (g).
(“Local Additions and Modifications to Section 1803 ‘Geotechnical Investigations’ of the 2010 California Building Code” added 7-31-2012 by O-20187 N.S.; effective 8-30-2012.)
(Retitled to “Local Additions and Modifications to Section 1803 ‘Geotechnical Investigations’ of the California Building Code” and amended 4-6-2016 by O-20624 N.S.; effective 5-6-2016.)
(Amended 4-9-2020 by O-21181 N.S.; effective 5-9-2020.)
(Amended 5-8-2023 by O-21642 N.S.; effective 6-7-2023.)
(Amended 8-5-2024 by O-21859 N.S.; effective 9-4-2024.)
(Amended 3-3-2026 by O-22080 N.S; effective 4-22-2026.)
