Walnut Municipal Code Ch. 2.04 County Building Codes

A. Adopted.

1. There is hereby adopted by reference, except as hereinafter provided, that certain Building Code Chapters 98 and 99 known and designated as portions of Title 26 of the Los Angeles County Code Chapters 98 and 99, Los Angeles County Ordinance No. 25-5683, adopted November 25, 2025, as contained in the 2026 Edition of the Los Angeles County Building Code based on the 2024 International Building Code as published by the International Code Council, as amended by Los Angeles County Ordinance No. 25-5683, effective January 1, 2026, and such code shall be and become the Unsafe/Rehabilitation Code of the City, regulating the unsafe or dangerous habitation, erection, construction, enlargement, alteration, repair, moving, removal, demolition, conversion, occupancy, use, height, area, and maintenance of all structures and certain equipment therein specifically regulated, providing penalties for violation of such code.

2. At least one copy of said Building Code shall be kept on file in the office of the Building Official and shall be maintained by said Building Official for the use and examination by the public.

3. In the event of any conflict or ambiguity between any provisions contained in this code and any provisions of the Walnut Municipal Code, the Walnut Municipal Code shall control.

B. Definitions. Whenever any of the following names or terms are used in the Los Angeles County Code Chapters 98 and 99, Unsafe/Rehabilitation Code of the City, each name or term shall be deemed and construed to have the meaning ascribed to it in this section as follows:

"Appeals Board"

means the City Manager of the City of Walnut or other hearing officer as outlined in Chapter 3.36 of the Walnut Municipal Code.

"Building Official"

means the Building Official of the City of Walnut.

"City"

means the City of Walnut.

"County" or "County of Los Angeles"

means the City of Walnut.

"District Attorney"

means the City Prosecutor of the City of Walnut.

C. Amendments. Sections 9929 and 9916 of said Los Angeles County Code shall be modified as follows:

1. Section 9929 Collection. Collection of fees shall be consistent with that outlined in Sections 3.36.200 to 3.36.250 of the Walnut Municipal Code.

2. Section 9916 Posting of Signs. The Building Official may cause to be posted at such substandard building or property a notice of substandard building or property and/or sign to read: "UNSAFE - DO NOT USE OR OCCUPY THIS BUILDING." Such sign may contain such additional information and warnings as in the opinion of the Building Official are expedient. Such notice or sign shall remain posted until the required repairs, demolition, removal, barricading, or property cleanup is completed. Such notice or sign shall not be removed without permission of the Building Official and if the substandard building has been ordered vacated, no person shall enter except for the purpose of making the required repairs or the demolishing of the substandard building.

(Ord. 19-11, §§ 3—5; Ord. 22-10, §§ 3—5; Ord. 25-07, 12/10/2025)

A. There is hereby adopted by reference, except as hereinafter provided, that certain Building Code known and designated as Title 26 of the Los Angeles County Code, Los Angeles County Ordinance No. 25-5683, adopted November 25, 2025, as contained in the 2026 Edition of the Los Angeles County Building Code based on the 2024 International Building Code as published by the International Code Council, as amended by Los Angeles County Ordinance No. 25-5683 including Appendix I and J, effective January 1, 2026, and such code shall be and become the Building Code of the City, regulating the erection, construction, enlargement, alteration, repair, moving, removal, demolition, conversion, occupancy, use, height, area and maintenance of all structures and certain equipment therein specifically regulated, regulating grading within the City, providing for the issuance of permits and collection of fees therefor, providing penalties for violation of such code and declaring and establishing fire zones.

B. At least one copy of said Building Code shall be kept on file in the office of the Building Official and shall be maintained by said Building Official for the use and examination by the public. In the event of any conflict or ambiguity between any provisions contained in the code and any amendment thereto, or additions thereto, contained in this chapter, the amendment or addition thereto contained in this chapter shall control.

C. In the event of any conflict or ambiguity between any provisions contained in the Building Code and any provisions of the Walnut Municipal Code, the Walnut Municipal Code shall control.

(Ord. 19-11, § 6; Ord. 22-10 § 6; Ord. 25-07, 12/10/2025)

A. Section 101 Amended—Title. Section 101 of said Los Angeles County Building Code is amended to read as follows:

Section 101. Title.

Section 2.04.020 shall be known as the "Building Code," may be cited as such, and will be referred to herein as "this code." The provisions of said section applying to dwellings, lodging, houses, hotels, apartment houses, convents, monasteries or other uses classified by this code as Group R-1 or R-3 Occupancy and including Chapters 1, 2, 3, 4, and 98 and 99 is and may be cited as the "Housing Code."

B. Section 202 Amended—Definitions. Section 202 of said Los Angeles County Building Code is amended to read as follows:

Section 202. Definitions.

Notwithstanding other definitions in this section, the following names or terms shall be added as amended definitions for this section where not indicated or each such name or term provided and defined in this section shall be deemed and construed to have the meaning ascribed to it in this section.

"Board of Appeals"

shall mean the City Manager of the City of Walnut or other hearing officer as outlined in Chapter 3.36 of the Walnut Municipal Code.

C. Appendix J—Grading Amended—County Building Official. Appendix J of said Los Angeles County Building Code is amended to make reference that when "Building Official" is indicated it would mean "City Engineer."

D. Section Appendix J107.10, Rodent Control—Added. Section J107.10 of the Los Angeles Building Code is amended to read as follows:

J107.10 Rodent Control. Excavation involving more than 1,000 cubic yards on vacant land must have a certified pest/rodent control service, licensed by the California Department of Food and Agriculture and Los Angeles County Agriculture Department, determine if there is a rodent problem at the project site. If there is a rodent problem, the contractor/developer must provide a rodent control and/or extermination program prior to commencement of excavation. Such rodent control and/or extermination program must comply with the eradication methods specified by the pest/rodent control service, until the service can provide written certification to the city that there is 90% control of rodents. The certification shall be valid for a period of 30 days. Where the certification is over 30 days, a re-certification is required.

E. Building Permit Required for Recreational Courts. Notwithstanding the provisions of Section 2.04.020 of the Walnut Municipal Code, Title 26 of the Los Angeles County Building Code is amended by requiring building permits for the construction of tennis courts and other courts used for recreational purposes. Designs for tennis courts and other recreational courts shall provide for adequate and sufficient drainage from all impervious surfaces and shall protect against erosion on adjacent properties.

F. Sections 406.2.4 and 406.3.3 Amended—Garage Floor Surfaces and Carports.

Section 406.2.4 of the California Building Code shall be amended as follows:

Section 406.2.4. Parking Area Floor surface.

In areas where motor vehicles are stored or operated in private carports or garages, floor surfaces shall be of concrete, having a uniform thickness of not less than three and one-half inches or other hard, non-absorbent, and noncombustible surface deemed equivalent by the Building Official.

The area of floor used for parking of automobiles or other vehicles shall be sloped to facilitate the movement of liquids to drain or toward the main vehicle entry doorway.

Section 406.3.3 of the California Building Code shall be amended as follows:

406.3.3 Carports. Carports shall be open on at least two sides. Carport floor surfaces shall be approved noncombustible material listed in Section 406.3.3. Carports not open on at least two sides shall be considered a garage and shall comply with the requirements for private garages.

G. Section 9906 Amended—Building Rehabilitation Appeals Board. Section 9906 of said Los Angeles County Code shall be modified as follows:

Section 9906 Building Rehabilitation Appeals Board. The Appeals Board shall follow that outlined in Section 3.36.130 of the Walnut Municipal Code.

H. Sections 1505.1 and 1505.1.3 Amended—Fire-Retardant Roofs. Section 1505.1 of said Los Angeles County Building Code is amended as follows:

Table 1505.1 is hereby amended, by the deletion of Table 1505.1 and the addition of a new Table 1505.1 thereto, to read as follows:

TABLE 1505.1 MINIMUM ROOF COVERING CLASSIFICATIONS TYPES OF CONSTRUCTION

Section 1505.1.3 is hereby amended, by the deletion of the entire section and the addition of a new section thereto, to read as follows:

1505.1.3 Roof Coverings Within all Other Areas. The entire roof covering of every existing structure where more than 50% of the total roof area is replaced within any one-year period, the entire roof covering of every new structure, and any roof covering applied in the alteration, repair or replacement of the roof of every existing structure, shall be a fire-retardant roof covering that is at least Class A.

I. Section 3109.4.4 Amended—Private Swimming Pools. Section 3109.4.4 is amended to clarify that pool barriers which are already in the code are scoped so as to apply on all private swimming pools as follows.

Amend Section 3109.4.4.1 by adding the following definition:

PRIVATE POOL, is any structure intended for swimming, recreation bathing or wading that contains water over 18 inches in depth. This includes in-ground, above-ground and on-ground pools; hot tubs; spas and fixed-in-place pools.

Section 3109.4.4.2 is modified by deleting the first paragraph in its entirety and a new paragraph is substituted to read as follows:

3109.4.4.2 Construction permit; safety features required. Commencing, January 1, 1998 except as provided in Section 3109.4.4.5, whenever a construction permit is issued for construction of a new private pool at a residence, it shall have an enclosure surrounding the property and between house and pool complying with Section 3109.4.4.3 and, it shall be equipped with at least two of the following safety features:

1. The pool shall be isolated from access to a home by an enclosure that meets the requirements of Section 3109.4.4.3.

2. The pool shall incorporate removable mesh pool fencing that meets American Society for Testing and Materials (ASTM) Specifications F2286 standards in conjunction with a gate that is self-closing and self-latching and can accommodate a key lockable device.

3. The pool shall be equipped with an approved safety pool cover that meets all requirements of the ASTM Specifications F1346.

4. The residence shall be equipped with exit alarms on those doors providing direct access to the pool.

5. All doors providing direct access from the home to the swimming pool shall be equipped with a self-closing, self-latching device with a release mechanism placed no lower than 54 inches (1,372 mm) above the floor.

6. Swimming pool alarms that, when placed in pools, will sound upon detection of accidental or unauthorized entrance into the water. These pool alarms shall meet and be independently certified to the ASTM Standard F2208 "Standards Specification for Pool Alarms" which includes surface motion, pressure, sonar, laser and infrared type alarms. For purposes of this article, "swimming pool alarms" shall not include swimming protection alarm devices designed for individual use, such as an alarm attached to a child that sounds when the child exceeds a certain distance or becomes submerged in water.

7. Other means of protection, if the degree of protection afforded is equal to or greater than that afforded by any of the devices set forth in items 1-4, and have been independently verified by an approved testing laboratory as meeting standards for those devices established by the ASTM or the American Society of Testing Mechanical Engineers (ASME).

J. Section 1809.4 Amended—Foundations on Expansive Soil. Section 1809.4 of the California Building Code is hereby amended to read, in words and figures, as follows:

Section 1809.4. Foundations on Expansive Soil.

Unless otherwise specified by a registered Geotechnical Engineer, foundation systems within the City of Walnut are considered to be on expansive soils and shall be constructed in a manner that will minimize damage to the structure from movement of the soil. Slab-on-grade and mat-type footings for buildings located on expansive soils may be designed in accordance with the provisions of Section 1808.6.2 or such other engineering design based upon geotechnical recommendation as approved by the Building Official. Where such an approved method of construction is not provided, foundations and floor slabs shall comply with the following requirements:

1. Depth of foundations below the natural and finish grades shall be not less than 24 inches for exterior foundations and 18 inches for interior foundations.

2. Exterior walls and interior bearing walls shall be supported on continuous foundations.

3. Foundations shall be reinforced with at least two continuous one-half-inch diameter deformed reinforcing bars top and bottom. Two bars shall be placed within four inches of the bottom of the foundation and two bars within four inches of the top of the foundation.

4. Concrete floor slabs on grade shall be cast on a four-inch fill of coarse aggregate or on a moisture barrier membrane. The floor slabs shall be at least three and one-half inches thick and shall be reinforced with welded wire mesh or deformed reinforcing bars. Welded wire mesh shall have a cross-sectional area of not less than five-hundredths square inch per foot each way. Reinforcing bars shall have a diameter of not less than three-eighths inch and be spaced at intervals not exceeding 24 inches in each direction.

5. The soil below an interior concrete slab shall be saturated with moisture to a depth of 18 inches prior to placing the concrete slab.

K. Section 501.2 Added—Premises Identification. Section 501.2 of said Los Angeles County Building Code is amended to read as follows:

a. Premises Identification (house number) shall be installed to a size, color and location as follows:

Residential Units—A minimum of 4 inches in height in a color contrasting with building, monument sign or mailbox color and to be visible from the street adjacent to a subject property. If a building is set back from the street further than 50 feet, the house number shall be displayed in a manner to be clearly visible from the street.

Commercial & Industrial Units—Same as residential but to include the same provision for suites and for units including street numbers. In the case of business/commercial/industrial parks with internal private drives/streets, all individual units/suites shall have numbers clearly visible from said drives/streets.

Maintenance—All required house numbers shall be maintained in accordance with the placement requirements.

(Ord. 19-11, §§ 7, 9—13, 15; Ord. 22-10, §§ 7, 9—13, 15; Ord. 25-07, 12/10/2025)

Development standards relative to grading within the City of Walnut are hereby established to complement the provisions set forth in Appendix Chapter J of the Los Angeles County Building Code as currently adopted and as may be amended from time to time. In cases of conflict between the provisions of the Los Angeles County Building Code and these development standards, the development standards shall prevail as to design concepts, nature and scope of permitted earthwork development, and administration of the permit process. The Los Angeles County Building Code shall prevail as to geotechnical and engineering design and construction.

A. General Requirements. All grading work shall conform to the Walnut Building Code, Municipal Code Sections 2.04.040 and 2.04.030(D) and Chapter 2.40 regarding the hauling of earth materials, and all City rules and regulations.

B. Development Standards.

1. Minimize Mass Grading. Development projects shall be designed wherever possible to minimize the effects of mass grading of hillside areas and to provide the most natural appearance and to preserve natural terrain. Development below the ridgelines and in the low lands are encouraged. The preservation of steeper hillsides in their natural state is encouraged.

2. Design Complete Landscaping Plans for Mitigation of Grading. Landscape plans shall indicate sufficient permanent fire-resistant plantings (preferably native) with adequate root systems to protect slopes from erosion and slippage and to minimize the visual effects of grading and construction. Any new landscape materials introduced as transition plantings shall be used to integrate the manmade and natural environments and to screen and soften the visual impact of development. Landscape materials shall also provide diversity within the developed areas. The City guidelines shall be used in considering the appropriate plant material. Temporary or permanent irrigation systems will be necessary to sustain the plant materials selected.

3. The proposed grading shall be designed to minimize adverse environmental effects on surrounding property or the permitted use thereof.

4. The proposed grading plan, when compared to possible alternative plans which would serve the same function, will result in the most natural appearance and preservation of natural terrain and water courses possible.

5. No cut or fill slopes shall be created which exceed 30 feet in vertical height. The Planning Commission may permit slopes exceeding this dimension where the slopes will be the result of earth contouring or which the Planning Commission finds will result in a natural appearance and will create no geological or erosion hazards.

6. Shaping of Slopes. All manufactured slopes adjoining the natural topography shall be contour graded so as to present a natural appearance and blend with the natural topography. This contour grading shall be designed and constructed in such a manner that the final earth form has a natural appearance. This is to be accomplished by rounding and smoothing sharp, angular forms, and avoiding flat, two-dimensional surfaces.

7. Shaping of slopes adjacent to public streets. Cut or fill slopes rising from public streets shall be designed to vary in form and magnitude so as to avoid long segments of uniform configuration.

8. Areas adjacent to major natural drainage swales shall be kept in their natural state as much as practical, consistent with the need to minimize flood and erosion hazards. Open greenbelt swales and adequate setbacks for development are a preferred alternative to undergrounding or open concrete lined channels. Natural drainageways shall be stabilized sufficiently to minimize channel erosion.

Where channelization projects are found necessary, they shall be part of a larger open space system, be landscaped to blend with the surroundings, and include trails and linear parks along their banks as part of the overall open space system.

9. Sediment catchment basins and/or other erosion/siltation control devices shall be constructed and maintained in accordance with an overall erosion control plan.

10. The overall drainage system shall be completed and made operational at the earliest practical time during construction.

11. Roadway design should reflect rural rather than urban character and have sensitive alignments which preserve the natural topography and avoid environmentally sensitive areas.

12. Grading plans shall include mitigating measures which will reduce to acceptable safety levels of any underground water seepage problems which may occur because of increased irrigation, rainfall, or alteration of the natural contours.

13. Development which borders permanent open space shall provide for fire hazard reduction zones in accordance with fire protection guidelines. Responsibility for maintenance of these buffer areas shall be provided for in the project proposal.

14. Modifications of these standards may be permitted by the Planning Commission where it can be demonstrated that strict interpretation of such standards will prove to be impractical due to the nature of the terrain and such modification will not be detrimental to the environment.

C. Procedures. The requirements and procedures set forth in this section are intended to supplement and be used simultaneously with requirements and procedures set forth in the City’s zoning and subdivision ordinances and regulations, environmental review process and the City’s building and development codes.

1. If the proposed final grading plan has elevations which vary from the approved tentative map elevations by more than three feet at the periphery of the development or more than 10 feet within the interior of the development, the grading plan shall be submitted to the Planning Commission for their approval.

2. If a grading plan proposes a change in elevation of five feet or more from existing elevation and a development is not involved which would require Planning Commission review or approval, the grading plan shall be submitted to the Planning Commission for their discretionary approval. Notwithstanding the foregoing, a grading plan submitted for a classroom facility exempt from the City’s zoning ordinance pursuant to Government Code Section 53094, shall be submitted to the City’s Engineer and Building Official and subject to administrative review and approval pursuant to technical design and construction standards of on-site improvements which affect grading and drainage and shall not be subject to discretionary review by the Planning Commission.

3. Before starting work, the project boundaries will be marked in sufficient detail to allow verification of proper clearances.

4. Where deemed necessary by the City Engineer, construction fencing will be placed so as to protect adjacent properties from slope sluffing.

5. Where deemed necessary by the City Engineer, temporary drainage protective devices (such as polyethylene lined berms or sand bag berms) shall be placed to control irrigation and storm drainage waters.

6. Where deemed necessary by the City Engineer, permanent drainage protective devices shall be placed to control irrigation and storm drainage waters.

7. Erosion control planting shall be installed at the earliest practical date following rough grading, or as directed by the City Engineer.

8. Sufficient details shall be incorporated into the grading plan to identify the nature and magnitude of the plantings to be placed on the project.

9. Where property is released to a third-party before slope erosion control planting is established, the permittee shall formulate mutually agreeable arrangements with the third-party regarding seeding, irrigation, weeding, fertilization, etc.

10. Verification of a complete soil and geologic analysis is required.

11. The following reports shall be submitted for staff and Planning Commission review:

a. An engineering geologic investigation based on the proposed grading plan and including adequate description of the geology of the site and conclusions and recommendations regarding the effect of geologic conditions on the development;

b. A soils engineering investigation based on the proposed grading plan and including data regarding the nature, distribution, and strength of soils, conclusions and recommendations for grading procedures, and design criteria for corrective measures.

12. In addition to all materials and procedures required by the City’s subdivision, zoning, building and grading regulations and environmental review procedures applicable to projects falling within the scope of this section, submittal of the following application materials shall be required for all projects provided herein:

a. A plan drawn to scale prescribed by the City Planner, but not less than a scale of 1″ = 100′, reflecting the proposed project, including representations of property lines and all recorded and proposed easements and public rights-of-way;

b. A topographical map of the project site and all adjacent terrain located within 50 feet of the project boundaries; this map shall be drawn to the same scale as the site plan or plot plan required in paragraph (a) above, with a maximum contour interval of 10 feet;

c. A complete grading plan for the project drawn to the same scale as prescribed above;

d. A tree map drawn to the same scale as prescribed above, locating existing trees or clusters of trees on the project site with a trunk diameter of six inches or greater;

e. A construction Management Plan including haul route designations and submittals relating to hauling earth materials required in accordance with Walnut Municipal Code Chapter 2.40 or as required by the City Engineer.

13. In addition to the materials listed above, if deemed necessary by the City Planner or the Planning Commission, to adequately review any proposed hillside development project, the City Planner may require submittal of any or all of the following materials:

a. A hydrology report which shall include, but not be limited to, the hydrologic conditions on the site, possible flood inundation, downstream flood hazards, natural drainage courses, conclusions and recommendations regarding the effect of hydrologic conditions on the proposed development, opinions and recommendations covering the adequacy of the sites to be developed, and design criteria to mitigate any identified hydrologic hazards consistent with these regulations. This report shall account for all runoff and debris from tributary areas and shall provide consideration for each lot or dwelling unit site in a proposed development project. Runoff and debris amounts shall be computed using the Los Angeles County Flood Control District criteria and methodology. This investigation and report shall be completed by a licensed Civil Engineer experienced in the science of hydrology and hydrologic investigation.

b. A landscaping plan which accurately shows: (1) the final disposition of all existing trees, as specified in paragraph (13)(a) above; and (2) the type and extent of proposed landscaping, including provisions for ongoing maintenance and irrigation thereof. Specific consideration should be given to the planting of manmade slopes to insure slope stability. Maintenance provisions for vegetation associated with roadways and with private driveways of more than 150 feet in length or serving more than one building site should be included. This plan shall be drawn to the same scale as is prescribed for the application materials required by paragraph (13)(a) above.

14. The requirement to submit any or all of the materials above may be waived by the City Planner, under the following conditions:

a. The existence of recently completed and satisfactory reports covering the same subject matter on the same site;

b. Inclusion of any or all of the above as part of an environmental report or negative declaration if either is required or has been satisfactorily completed for the proposed development on the site;

c. The existence of reports as described in paragraphs (14)(a) and (14)(b) above, previously prepared for a site or area adjacent to the project site, if the project site and such adjacent site or area may reasonably be expected to possess similar characteristics relative to the development issues addressed by this section.

15. The application fee for a grading project under this resolution shall be as set by resolution of the City Council.

D. Planning Commission Review. Applicants for projects referred to the Planning Commission in accordance with this section shall be subject to the approval of the Planning Commission. A project application considered by the Planning Commission under this section shall be reviewed for conformance with the standards and criteria set forth in this section and for consistency with other community standards, including the following:

1. The project will not be detrimental to the public health, safety or general welfare;

2. The project will not adversely affect the orderly development of this or other property within the City;

3. The project will not adversely affect the goals and policies set forth in the City’s General Plan;

4. Approval of the project will not constitute a grant of special privilege inconsistent with the limitations upon other projects and/or properties in the vicinity and zone in which the proposed project site is located;

5. The project will not create a nuisance, hazard or enforcement problem within the neighborhood or the City or require the City to provide an unusual or disproportionate level of public services;

6. The project will not encourage development inconsistent with the character of the existing development within the neighborhood; and

7. There are special conditions or unique characteristics of the subject property and its location or surroundings which justify deviation from one or more of the standards set forth in this section to permit project development.

E. Maintenance and Alteration.

1. The City may implement, on an annual basis, a slope maintenance inspection program designed to identify significant maintenance deficiencies. The cost of such an inspection shall become a lien on the benefitted property under procedures established by law.

Further, the City may cause remedial work to be done and recover the costs therefor through the lien process.

2. No one shall construct fences, walls, decking, structures, landscaping improvements or any other works so as to block or improperly divert drainage runoff on his or her property.

(Ord. 19-11, § 8; Ord. 22-10, § 8)

Note: Former § 2.04.050, Designation and amendments for fire zone, derived from Ord. 19-11; amended by Ord. 22-10; Ord. 25-03; was repealed by Ord. 25-07, 12/10/2025.

All fees and charges prescribed and set forth in Section 107, Fees, of the Los Angeles County Building Code, currently adopted version, incorporated by reference as the Building Code of the City, are hereby modified by increasing the amount of each and all of such fees and charges to an amount equal to twice the amount charged for the same services and permits by the County.

(Ord. 19-11, § 16; Ord. 22-10, § 16; Ord. 25-07, 12/10/2025)

Every person who violates any of the provisions of this code is guilty of a misdemeanor and each such person shall be deemed guilty of a separate offense for each and every day or portion thereof during which any violation of any of the provisions of this code is committed, continued or permitted, and upon conviction is punishable by a fine not exceeding $1,000.00 or by imprisonment in the County Jail for a period not exceeding six months or by both such fine and imprisonment.

In the event of any conflict or ambiguity between any provisions contained in the Los Angeles County Building Code and any provisions of the Walnut Municipal Code, the Walnut Municipal Code shall control.