Part 3 — Development Projects

All projects fitting the category descriptions below (hereinafter called “regulated projects”) must implement low impact development source control, site design, and stormwater treatment measures. The categories of regulated projects are:

(a) New development projects or redevelopment projects.

New development or redevelopment projects that create and/or replace 5,000 square feet or more of impervious surface (collectively over the entire project site). This category includes commercial, industrial, residential housing subdivisions (i.e., detached single-family home projects), multi- family attached subdivisions (i.e., town homes, condominiums, and apartments), mixed-use, new and reconstructed private roads and private trails, and public projects (other than public road and trail projects), including sidewalks and any other portions of the public right-of-way that are developed or redeveloped as part of the projects.

Specific exclusions that apply to this category are listed in subsection (e) below. Public works projects that are additionally excluded from this category – unless they create and/or replace 5,000 contiguous square feet or more of impervious surface – include the following examples: sidewalk gap closures, sidewalk section replacement, and Americans with Disabilities Act-compliant curb ramps.

Where a redevelopment project results in an alteration of 50% or more of the impervious surface of a previously existing development that was not subject to this part, stormwater treatment measures shall be designed and sized to treat stormwater runoff from the entire redevelopment project. Where a redevelopment project results in an alteration of less than 50% of the impervious surface of a previously existing development that was not subject to this part, stormwater treatment measures must be designed and sized to treat stormwater runoff from the new and/or replaced impervious surface of the project.

The calculations in this subsection shall include portions of the public right-of-way that are developed or redeveloped as part of the regulated project.

(b) New or widening road projects.

Any of the following types of road projects (including both public and private road projects) that create 5,000 square feet or more of newly constructed contiguous impervious surface, and that fall under the planning and building authority of the city:

(1) Construction of new streets or roads, including sidewalks and bicycle lanes built as part of the new streets or roads.

(2) Widening of existing streets or roads with additional traffic lanes. Where the addition of traffic lanes results in an alteration of 50% or more of the impervious surface of an existing street or road within the project that was not subject to this part, stormwater treatment measures must be designed and sized to treat stormwater runoff from the entire street or road that had additional traffic lanes added. Where the addition of traffic lanes results in an alteration of less than 50% of the impervious surface of an existing street or road within the project that was not subject to this part, stormwater treatment measures shall be designed and sized to treat stormwater runoff from only the new traffic lanes. However, if the stormwater runoff from the existing traffic lanes and the added traffic lanes cannot be separated, any onsite treatment system shall be designed and sized to treat stormwater runoff from the entire street or road. If an offsite treatment system is installed or in-lieu fees paid in accordance with MRP Provision C.3.e or Section 16.11.180(c), the offsite treatment system or in-lieu fees must address only the stormwater runoff from the added traffic lanes.

(3) Construction of impervious trails that are greater than or equal to ten feet wide or are creek-side (within 50 feet of the top of bank).

(4) Specific exclusions to this subsection include the following:

(i) Sidewalks built as part of new streets or roads and built to direct stormwater runoff to adjacent vegetated areas;

(ii) Bicycle lanes built as part of new streets or roads, but that are not hydraulically connected to the new streets or roads and that direct

stormwater runoff to adjacent vegetated areas;

(iii) Impervious trails that direct stormwater runoff to adjacent vegetated areas, or other non-erodible permeable areas, preferably away from

creeks or towards the outboard side of levees, where those areas are at least half as large as the contributing impervious surface area;

(iv) Sidewalks, bicycle lanes, or trails constructed as pervious pavement systems; and

(v) Caltrans highway projects and associated facilities.

(c) Road reconstruction and utility trenching projects.

Road projects that involve the reconstruction of existing streets or roads, which create and/or replace at least one contiguous acre of impervious surface and that are public road projects and/or fall under the planning and building authority of the city, including sidewalks and bicycle lanes that are built or rebuilt as part of the existing streets or roads. This regulated project category includes utility trenching projects which are, on average, over the entire length of the project, greater than or equal to eight feet wide. It also includes public pavement maintenance practices listed in subsection (e)(3) if they are part of a project that otherwise meets the requirements of this section.

Where the reconstruction project results in an alteration of greater than or equal to 50% of the impervious surface of an existing street or road within the project that was not subject to this part, stormwater treatment measures must be designed and sized to treat stormwater runoff from the entire street or road that was reconstructed. Where the reconstruction project results in an alteration of less than 50% of the impervious surface of an existing street or road within the project that was not subject to this part, stormwater treatment measures shall be designed and sized to treat stormwater runoff from only the new and/or replaced impervious surface within the project footprint. However, if the stormwater runoff from the existing impervious surface and the added impervious surface cannot be separated, any onsite treatment system shall be designed and sized to treat stormwater runoff from the entire street or road. If an offsite treatment system is installed or in-lieu fees paid in accordance with MRP Provision C.3.e or Section 16.11.180(c), the offsite treatment system or in-lieu fees must address only the stormwater runoff from the added impervious surface.

(d) Large detached single-family home projects.

Detached single-family home projects that create and/or replace 10,000 square feet or more of impervious surface (collectively over the entire project site) and are not part of a larger development or redevelopment plan regulated under “new development projects or redevelopment projects” – see subsection (a) above. This regulated project category includes the addition of an accessory dwelling unit (ADU) on an existing parcel with one single-family home that is not part of a subdivision or plan.

Where a single-family home project results in an alteration of 50% or more of the impervious surface of a previously existing project that was not subject to this part, stormwater treatment measures shall be designed and sized to treat stormwater runoff from the entire project. Where a single- family home project results in an alteration of less than 50% of the impervious surface of a previously existing project that was not subject to this part, stormwater treatment measures shall be designed and sized to treat stormwater runoff from the new and/or replaced impervious surface of the project. The calculations in this subsection shall include portions of the public right-of-way that are developed or redeveloped as part of the regulated project.

(e) Exemptions: For redevelopment projects and road reconstruction projects:

(1) The following interior and exterior practices are excluded:

(i) Interior remodels; and

(ii) Routine maintenance or repair such as roof or exterior wall surface replacement.

(2) The following pavement maintenance practices are excluded:

(i) Pothole and square cut patching;

(ii) Overlaying existing asphalt or concrete pavement with asphalt or concrete without expanding the area of coverage;

(iii) Shoulder grading;

(iv) Reshaping/regrading drainage systems;

(v) Crack sealing;

(vi) Pavement preservation activities that do not expand the road prism;

(vii) Upgrading from a bituminous surface treatment (e.g., chip seal) with an overlay of asphalt or concrete, without expanding the area of

coverage;

(viii) Applying a bituminous surface treatment to existing asphalt or concrete pavement, without expanding the area of coverage;

(ix) Vegetation maintenance; and

(x) Layering gravel over an existing gravel road, without expanding the area of coverage.

(3) The following pavement maintenance practices are not excluded.

(i) Removing and replacing asphalt or concrete pavement to the top of the base course or lower, or repairing the pavement base (including

repair of the pavement base in preparation for bituminous surface treatment, such as chip seal), as these are considered replaced impervious surfaces;

(ii) Extending the pavement edge without increasing the size of the road prism, or paving graveled shoulders, as these are considered new

impervious surfaces; and

(iii) Resurfacing by upgrading from dirt to gravel, to a bituminous surface treatment (e.g., chip seal), to asphalt, or to concrete; or upgrading

from gravel to a bituminous surface treatment, to asphalt, or to concrete, as these are considered new impervious surfaces.

(4) For a project consisting of a combination of exempted pavement maintenance practices and non-exempted pavement maintenance and/or

practices that fall under any other regulated project category, the parts of the project that are not exempt shall be evaluated as a regulated project.

(Ord. 5671 § 2 (part), 2025)

All regulated projects shall implement source control measures onsite that, at a minimum, comply with city regulations and the requirements of the MRP.

(Ord. 5671 § 2 (part), 2025)

All regulated projects must implement low impact development site design measures that, at a minimum, comply with city regulations and the requirements of the MRP.

(Ord. 5671 § 2 (part), 2025)

All regulated projects shall implement stormwater treatment measures onsite that, at a minimum, comply with city regulations and the requirements of the MRP. Stormwater treatment measures shall not be altered without permission from the Director.

(a) All regulated projects shall design, construct, maintain, and operate stormwater treatment measures for the entire duration that the project is in use in accordance with the MRP and city regulations. All regulated projects, except special projects, shall treat 100% of the amount of stormwater runoff identified in accordance with MRP Provision C.3.c requirements for the regulated project’s drainage area onsite or at a Joint Stormwater Treatment Facility per MRP Provision C.3.c, Chapter 16.11.180, and SCVURPPP and city specifications. LID stormwater treatment measures include harvesting and use, infiltration, evapotranspiration, and biotreatment. Stormwater treatment systems must be sized using one of the hydraulic sizing design criteria approved in MRP C.3.d.i. Any regulated project that does not comply with this requirement must meet the requirements for alternative compliance established in accordance with subsection (c) below.

(b) Special projects designed in a manner that meets the criteria of the MRP and city regulations shall be allowed to apply for incentive LID treatment reduction credits per the Water Board’s process outlined in the MRP.

(c) If a development project cannot install stormwater treatment measures in conformance with the requirements of the MRP and this chapter, the Director may approve alternative compliance and allow in-lieu measures and/or fees if made necessary by individual site conditions and in accordance with the MRP and city regulations. Projects shall still meet all regulated project requirements but may be allowed to do so partially onsite or fully off-site or through payment of in-lieu fees. This approval shall occur prior to issuance of Planning and Land Use Entitlement under Title 18 of this Code, or a building permit if no entitlement is required, unless the Director allows an exception.

(Ord. 5671 § 2 (part), 2025)

(a) Prior to the issuance of a planning and land use entitlement under Title 18 of this Code, or a building permit if no entitlement is required, for a regulated project, the applicant or designee of a regulated project shall submit a certification by a qualified third-party reviewer acceptable to the Director that the design of the project complies with the requirements of this chapter, city regulations, the MRP, and any plan review comments provided by the Director. After the project is constructed, the applicant or a designee shall submit a written certification by a qualified third-party reviewer acceptable to the Director that a regulated project was constructed or installed in accordance with the city-approved plans and drawings and per city regulations and the MRP.

(b) The third-party reviewer shall be an independent civil engineer, licensed architect, or landscape architect registered in the State of California, shall have current training in stormwater treatment measure design and construction, and meet other requirements set forth by the city regulations. The third-party reviewer shall not be any consultant or contractor hired to design and/or construct a stormwater treatment measure for the regulated project.

(c) Certifications and documentation required by this section shall be in the form prescribed by the Director.

(d) Applicant is responsible for ensuring that the stormwater treatment measure is constructed according to the design approved by the Director.

(Ord. 5671 § 2 (part), 2025)

Regulated projects shall comply with applicable design and construction guidelines and standard specifications included in the city’s Green Stormwater Infrastructure Plan and related documents, including design guidelines, standard specifications, and other requirements as established by the Director.

(Ord. 5671 § 2 (part), 2025)

(a) Applicability. All regulated projects that result in the creation and/or replacement of one acre (43,560 square feet) or more of impervious surface and result in a net increase in impervious surface over the pre-project condition shall implement hydromodification management measures.

(b) Exemption. Projects located in areas designated as exempt from hydromodification management measure requirements on the Hydromodification Applicability Map contained in the MRP are exempt from this requirement.

(c) Hydromodification management measures shall be designed and implemented in accordance with city regulations, MRP requirements, and other applicable regulations and policies.

(d) All hydromodification management measures are subject to inspection and approval by the Director.

(Ord. 5671 § 2 (part), 2025)

All regulated projects shall comply with the following:

(a) The property owner(s), its administrators, successors, and any other persons responsible for the management of the property, including any homeowner's association, shall take all necessary actions to ensure that the stormwater treatment and hydromodification management measures are properly maintained so that all measures continue to operate as originally designed and approved for the life of the project. These measures shall not be removed, replaced, or amended without the Director’s approval.

(b) Before a building permit is issued, a maintenance agreement shall be submitted to the Director describing all required stormwater treatment and hydromodification management measures, including all information and documentation required by the Director. This agreement shall be approved by the Director, signed by the City Attorney or designee and property owner(s), and recorded with Santa Clara County. If property changes ownership at any time, the new property owner(s) shall take on responsibility for maintenance of any stormwater treatment and hydromodification management measures located on that property and shall adhere to the operations and maintenance agreement.

(c) The operation and maintenance of the measures shall at all times be conducted in accordance with the terms and conditions of the approved maintenance agreement.

(d) Any stormwater treatment measure and/or hydromodification management measure constructed through an alternative compliance option (allowed by the Director per Section 16.11.180(c)) shall also have a maintenance agreement that complies with this section.

(Ord. 5671 § 2 (part), 2025)

16.11.150.

Development and redevelopment projects that require a planning and land use entitlement or building permit from the city but are not regulated projects shall implement LID Source Control and site design measures as required by city regulations and the MRP. The design and implementation of the measures shall be in accordance with the guidelines and technical specifications established by the Director, city regulations, and the MRP. LID features shall not be altered without permission from the Director.

(Ord. 5671 § 2 (part), 2025)

(a) Applicability. This section shall apply to any development project that requires a planning and land use entitlement review or building permit, except for minor projects such as those limited to signs, fences, and parking restriping that have no or minimal potential to create non-stormwater discharges.

(b) Development projects shall meet all applicable requirements of the Palo Alto regulations for stormwater pollution prevention and must be designed to accommodate best management practices described in Section 16.11.290 and city regulations, as applicable.

(Ord. 5671 § 2 (part), 2025)

(a) Applicability. This section shall apply to any project that includes the construction of a loading dock.

(b) The following requirements shall be met for all loading docks where applicable:

(1) The loading dock and surrounding area shall consist of impervious paving appropriate for the material(s) that will be loaded/unloaded to

avoid leaching into or degradation of paving.

(2) The loading dock shall be covered and protected from precipitation, stormwater runoff and stormwater run-on to minimize potential non-

stormwater discharges.

(3) The loading dock shall be designed to drain to the sanitary sewer system. Drains may be required to be equipped with a fail-safe shut-off

valve, normally closed, or equivalent device according to the type of materials or substances being transferred. Valve shall be immediately shut off if a spill of any size occurs and shall not be opened until the spill is completely remediated.

(Ord. 5671 § 2 (part), 2025)

(a) All new development projects shall meet the requirements of the Public Works Drainage Design Standards and the Santa Clara County Drainage Manual in effect at the time of submission of a complete planning application, or if no planning application is required for the development project, at the time of submission of a complete application for a building permit or excavation and grading permit, whichever occurs first.

(b) All redevelopment projects and remodels requiring a building permit or excavation and grading permit shall meet the requirements of the Public Works Drainage Design Standards provided by the Public Works Director for the portion of the site or facility being constructed, remodeled, or improved.

(c) Notwithstanding the foregoing provisions of this section, a project shall not be subject to the requirements of this section if the project does not include new drainage patterns or alter existing drainage patterns of the site.

(Ord. 5671 § 2 (part), 2025)

(a) All workers, contractors, subcontractors, and superintendents of construction sites of any size shall follow and implement all applicable provisions of stormwater management, pollution prevention, and erosion and sediment control plans and ensure that BMPs are in place to prevent potential pollutants from being tracked, mobilized, carried, transported, or discharged into the on-site storm drain inlet(s), city’s right-of-way, storm drain system, and receiving waters, as required by city regulations.

(b) Projects covered under the State of California Construction General Permit (CGP) shall also meet the requirements of this section. Project applicants shall provide to the city a copy of the notice of intent and notice of termination required under the CGP.

(c) Construction BMPs shall be in place until exterior impervious surfaces, the building shell, landscaping, and stormwater treatment measures are in place. In addition to BMPs generally applicable to construction sites year-round, all construction sites shall implement site-specific, seasonally and phase-appropriate BMPs as required by the Director.

(d) The Director is authorized to oversee, inspect, and require expedient compliance with the requirements of this section at all construction sites year-round. Inspections shall occur at a regular frequency established by the Director.

(e) Contractor/subcontractor requirements. The applicant shall be responsible for ensuring that its contractors and subcontractors comply with this section.

(Ord. 5671 § 2 (part), 2025)