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The 355

San Mateo County - Reference Excerpts

SAN MATEO COUNTY Planning, Building and Fire - Reference Excerpts

These fee schedules are new, approved 20241119, effective 20250101 and replace the older versions: Planning Fee Schedule and Building Fee Schedule and related Fire Feed Schedule.

Cross Reference: Relevant details for S17 Midcoast zone are described in the document here: County of San Mateo - Zoning Regulations 10-17-2023. The zoning regulations also contain sections that decribe the Coastal Development Permit.

Roughly speaking as of H2 2024, we are in a holding pattern in the Architecture and Design phase for a few reasons, category I in the list below.

The next key milestone that requires reaching closure with design drawing proposal and producing a set of forms are the processes with the phase gate related to the Coastal Development Permit.

Phase Summary

I. ARCHITECTURE AND DESIGN

The steps under this category center on iterations to reach an early plan set including drawings.

II. ENGINEERING DUE DILIGENCE

  • Geotechnical and Soils: foundation and drainage homework
  • Structural Analysis and Review
  • Identify and Mitigate Code Compliance or Non-conforming Issues - pre-existing on-site and/or in plan set

The iterations and steps under this category build on the settled working draft plan set drawings to work through due diligence engineering analysis to roll forward.

For example, make sure Parcel Coverage numbers add up and actions needed with Carport as one known Non-compliance are identified and taken. It is important that the coverage added by the structure does not create and obstacle to planning and review processes.

III. San Mateo County - PLANNING and REVIEW STEPS

IV. San Mateo County - BUILDING PERMIT PHASE

Reference these links for the Building Permit portals for San Mateo County.

Symbium Portal: https://symbium.com Accela Portal: https://aca-prod.accela.com/SMCGOV/Login.aspx

V. BUILD

Contractors, builders, engineers and artists - all need time to build the masterpiece.

VI. INSPECTION PHASE

Building inspections and finaling - the trust but verify steps…

Reference below for a detailed drill down into the Coastal Development Permit steps as a key phase gate.

Coastal Development: PERMIT

There are three variations to do homework around with specific expectations around Coastal Zone (CZ) projects in S-17 Midcoast specific to Coastal Development Permit steps. The Coastal Development Permit (Staff-Level) variant is the expected application step that is the working target. Reference the forms and regulations tables below and available at the links below.

NOTES:

  • The staff level review is effectively a set of forms with an approximate time: 2-4 Months and approximate fees: $1962 for CDP/Staff plus 3770 for CDRC as per guidelines on the staff level page, corrected for the 2025 fee updates.
  • Reference the key checklist C.3 and C.6 Development Review Checklist. The fine print here is that if or when the Carport is removed, in addition to the hardscape underneath in North and the driveway by the Garage removed and replaced with pervious pavers or rocks.
  • State and local ordinances require the County to notify surrounding owners or residents and the general public of most proposed projects and any required hearings. NOTE: word is that remodel in the back setback area does not start this clock - can go right to CDRC for CDP.

The C.3 and C.6 Development Review Checklist captures a formal calculation of existing, new and replaced impervious surface at the project site. The completed form is required for all projects requiring a Planning or Building permit that would result greater than 150 sq ft of new or replaced impervious surface. A completed form is required to be submitted at the time of permit application

Reference the following sections for an overview of the Steps, Forms and Regulations as relates to a Coastal Development Permit

SOURCE: Reference the outline in Coastal Development Permit (Staff-Level) for details, but here is the summary.

  1. Application Submission.
  2. Initial Application Review.
  3. Preliminary Research and Site Visit.
  4. Referral and Plan Check.
  5. Resubmittal (if applicable).
  6. Environmental Review (if required).
  7. Preparation of a Staff Report (if discretionary).
  8. Public Notification.
  9. Public Hearing (if discretionary).
  10. Permit Issuance.

Coastal Development: FORMS

Here are the forms from the staff level readout.

FORMSRequired: Yes/No
Coastal Development Permit Application - Companion PageYes
Environmental Information Disclosure FormYes
Planning Permit Application Form: see Planning Permit - View Permit Types, NB: Coastal Development Permit (Staff-Level)Yes
Biological Impact FormNo
C.3 and C.6 Development Review ChecklistMaybe. Decision keys off Carport square footage vs. Parcel Coverage

My read is that the Biological Impact Form stipulated by Local Coastal Program would not be required due to the remodel being on an pre-existing house in a developed neighborhood in El Granada and this requirement not being triggered based on no sensitive habitats in radius.

A Biological Impact Report is required for all proposed developments located within 100 feet of a Sensitive Habitat.

Coastal Development: REGULATIONS

Here are the regulations from the staff level readout.

Cross Reference: Review regulations listed below in the context of practices under: Coastal Development Permit (Staff-Level)

REGULATIONS
Local Coastal Program: https://www.smcgov.org/planning/local-coastal-program
Coastal Development District: reference document here: https://www.smcgov.org/planning/coastal-development-district
Coastal Development Permit Exemptions/Exclusion Worksheet: reference worksheet here: https://www.smcgov.org/planning/coastal-development-permit-exemptionsexclusion-worksheet

Cross reference the governing Coastal Development Permit to the relevant requirements for the County of San Mateo Planning Commission processes and steps. Read below for where that steps fits in the puzzle.

The Planning Commission is authorized by County ordinance to review the County General Plan and various development regulations and make recommendations on their adoption or amendment by the County Board of Supervisors. The Commission is also charged with reviewing and acting upon various development permits issued by the County. The County Planning Commission’s jurisdiction is generally limited to the unincorporated areas of the County (outside city limits). Each city in the County has its own planning commission.

COASTSIDE Design Review Committee

Based on adding a second story, my understanding is that Coastal Zone (CZ) specific CDRC review is unavoidable.

The key questions around design iterations to date when originally approaching a South Master above garage approach was a mix of ROW setaback and then Second Story Setback. Inconsistency and subjective aspects aroun Midcoast design standards and enforcement is the best way to summarize this - comparing information communicated to us from San Mateo County staff or volunteer appointed or community committee members against actual builds in progress (Miramar examples in latest set)

REFERENCE: Standards for Design for One- and Two-Family Residential Development in the Midcoast : https://www.smcgov.org/planning/midcoast-design-standards

  • Elements of Design (6565.20) (D) - 1. Building Mass, Shape and Scale - e. Wall Articulation, page 16:

(1) Require at least one step or off-set extending to grade on the long dimension of the house.

  • Elements of Design (6565.20) (D) - 1. Building Mass, Shape and Scale -  Daylight Plane / Facade Articulation, page 15:

The revised design became compatible with it’s neighbors by stepping back the second story and providing variation in the roof and building forms. … (2) Facade Articulation Option - Facade articulation shall be provided on all building sides, and is subject to approval by the Design Review Committee.

  • Elements of Design (6565.20) (D) - 2. Complement Other Structures in the Neighborhood - b. Views, p 10:

Possible methods to minimize view blockage include: locating living space where it would have less view impact, increasing the setback of second stories, lowering roof plate heights, and choosing roof forms that minimize mass. 

NOTE: The Midcoast stakeholders on San Mateo County staff and community commitees should consider recent work on the Peninsula, also in San Mateo County. Reference: > San Carlos Objective Design Standards ODS

The Midcoast Design Standards has language in places subjective and open to interpretation. My rough take - as one example - is to run design aspects such as Articulation through a filter such as on page 22 of San Carlos Objective Design Standards ODS, 20230315. Note the use of language like “one of the following…” which allows for some design creative but does provide a rule to check against.

COASTSIDE Fire Protection District

REFERENCE:

Basically, once the 50% number for Gross Floor Area is passed, the ordinance kicks in to require the dedicated water line and sprinkler retrofit for the entire main house.

  • Section-903.2.8.1.1 Automatic sprinkler systems installed in Group R-3, occupancies [added] shall conform to the following standards in addition to NFPA Standard 13D, currently adopted edition:
  1. Automatic sprinkler system coverage shall be provided throughout the residence to include all bathrooms, attached garages, and any interior rooms used for storage.
  2. An exterior bell shall be mounted in a location to be audible from the street upon activation of the required flow switch.
  3. An interior horn shall be mounted in a central location audible from the master bedroom upon activation of the required flow switch.
  4. A sprinkler head shall be mounted on a metal sprig above any attic access openings and where required by the AHJ.
  5. An inspector’s test valve shall be mounted to flow from the most remote area of the system in an accessible location.
  6. All group R, Division 3 occupancies shall require an automatic sprinkler system regardless of square footage.
  7. Accessory Dwelling Units shall conform to the most recent California State Fire Marshal’s Information Bulletin

Cross Reference:

Section 903.6.1 Where required. [added]

All existing buildings and structures, except for Group R-3 One and Two-Family Dwellings, shall be provided with an automatic fire sprinkler system when any of the following conditions occur: (A) The renovation of any structure and/or when combined with any additions to the structure, affects a gross floor area which exceeds fifty percent (50%) of the existing floor area of the structure.

Section 507.1.1 Fire Department Water Supply. [added]

  1. Fire Department Water Supply shall be required when one or more additions, alterations, or repairs, or combination thereof, in a two-year period, exceed more than 50% of the valuation of the facility or building. Exceptions:
  2. Any exemption otherwise allowable under the Fire Code as determined by the Fire Code Official
  3. Exterior improvements and work not requiring permits as provided in the Building Code
  4. Detached Group U occupancies or detached carports less than 1000 square feet. 4. Work requiring only a mechanical, electrical, plumbing, and/or demolition permit.

Section 503.1.2.1. Fire Department Access. [added]

  1. Fire Department Access shall be required when one or more additions, alterations, or repairs, or combination thereof, in a two-year period, exceed more than 50% of the valuation of the facility or building. Exceptions:
  2. Any exemption otherwise allowable under the Fire Code as determined by the Fire Code Official
  3. Exterior improvements and work not requiring permits as provided in the Building Code
  4. Detached Group U occupancies or detached carports less than 1000 square feet.
  5. Work requiring only a mechanical, electrical, plumbing, and/or demolition permit.

San Mateo County - Coastal Zone: Drainage Review

The drainage review processes are an area where review and requirements have evolved over time. These are important aspects due to (primarily) swales and lack of storm sewers. The corner lot nature of The 355 involves not just Planning and Building for San Mateo County but also brings in Public Works due to Right of Way considerations.

Specific to El Granada and The 355, a French drain added as a measure after house built to West would be a candidate to revise and evolve. That said, it is possible that due to this not being new construction on a previously undeveloped site - that an indepth Drainage Review may not be triggered.

REFERENCES:

From Guidelines for Drainage Review, excerpt below. Expected cost due to corner lot, Right of Way considierations $495 for fees plus requisite engineering work (geotechnical or soils).

  1. Post-development peak flow (runoff) and velocity must be less than or equal to pre- development peak flow and velocity in areas where there are no existing down stream storm drain systems. No additional runoff, caused by development, can cross property lines. In areas where there are existing storm drain systems, those systems must be of adequate size to accept the increased runoff, or, mitigation procedures must be taken. Mitigation procedures may include on-site storm drain detention or off-site storm drain improvements.

…

3. The use of dry wells to dispose of surface runoff may be allowed.

Note that these items typically must be produced by a registered civil engineer as supporting evidence.

  • drainage report
  • hydrologic study
  • hydraulic calculations
  • drainage improvement

Reference the excerpt below from Drainage Manual for general and high level guidelines.

Projects seeking a Planning and/or Building Permit that create and/or replace more than 150 square feet of impervious surface.

Relevant to work at The 355 is how a Carport that dates back to 70s or 80s, way before our time, could factor in to current Parcel Coverage math.

…

Drainage Review is generally performed by the County Planning & Building Department. However, projects that encroach in the public right-of-way (ROW) will be reviewed and permitted by the County’s Public Works Department in a separate permitting process that is not included in the scope of this Manual. These projects must not adversely affect existing drainage capacity of drainage facilities in the ROW. Projects that create a substantial amount of new impervious surface in the ROW may be subject to additional flow, velocity, and/or volume control requirements.

Basic Drainage Review

Reference the excerpt below for guidelines around the Basic Design Review scenario.

Section 3.1, p20:

  1. Review Section 3.2 and confirm that you can demonstrate compliance with the requirements through one or more of the three methods.
  2. Fill out Pages 1 and 2 and any other relevant worksheets of the stormwater checklist ( C.3 and C.6 Development Review Checklist). See Appendix 1 for step-by-step instructions on completing this checklist.
  3. Prepare a Site Plan for your project per the requirements listed in Section 3.3.
  4. Submit your completed Site Plan and stormwater checklist to the County of San Mateo Planning and Building Department.

Section 3.2, p21:

  1. There is no net increase in impervious area or change to existing drainage patterns within a drainage area (e.g. an existing garage is replaced by an accessory dwelling unit with a smaller footprint, or existing impervious patios or driveways are replaced with properly constructed permeable pavers or landscaping to compensate for new adjacent impervious roof areas).

  2. New stormwater flows are routed to an existing stormwater management feature (e.g. dry well, detention tank, or bioretention planter) that can accommodate the new flows. If known, provide dimensions of the existing feature and the existing drainage report that contains information about the existing feature. Use the sizing methodology in Section 4.2 to confirm that the existing feature can accommodate the new flows.

  3. All new and replaced impervious areas are drained to on-site landscaping that can accommodate new stormwater flows. To demonstrate this, identify the landscaped area(s) and all impervious areas (including existing, replaced, and new) that drain to the landscaped area. Calculate or estimate the average slope of the landscaped area. Check that the ratio of landscaped area to impervious area meets the minimum requirements in Table 3-1. If the slope of the landscaped areas is greater that 10%, the landscaped area is not suitable to manage stormwater flows, so you will need to use one of the other two methods to demonstrate compliance.

Section 3.3, p22:

Project parcel boundary › Limits of work › Show all existing, new, and replaced impervious surfaces on-site and their areas in square feet › Show all existing and proposed drainage features on-site, including roof gutter downspout locations › Provide slopes and direction of flow in the project vicinity. Ensure that surfaces adjacent to buildings are sloped away from buildings at 2% minimum for impervious surfaces and 5% minimum for pervious surfaces. › If new and/or replaced impervious areas are drained to landscaping: » Show how stormwater flows are conveyed to landscaping. » Specify splash blocks at downspouts to promote dispersion to landscaping or appropriate erosion control measures at the ends of any pipes used for conveyance. » Outline the landscaped area proposed to manage flows and provide the slope and area of landscaping in square feet. » If grass or groundcover is not planted in the area, specify 3” of mulch cover or functional equivalent.

Section 3.3, p23:

For proposed minor drainage features: » Specify diameters and material of new pipes. All proposed drainage pipes should be minimum 4” in diameter. » Vegetated swales should be minimum 4” deep as feasible with maximum 2:1 side slopes. Swales with flow paths greater than 2% should have appropriate erosion control measures (grass, rock, mulch, etc.) » Provide a cross section for all proposed swales and pervious pavements. » Stormwater is NOT allowed to be routed to foundation subdrains unless there is sufficient grade separation to prevent stormwater from inadvertently flowing to drain.

Prescriptive Drainage Review

Reference the excerpt below for guidelines around Prescriptive Design Review scenario. Based on right-of-way considerations because we are on a corner lot, we will likely need to deal with the trifecta of San Mateo County Planning, Building and Public Works.

Section 4.1, p 25:

  1. Fill out Pages 1 and 2 and any other relevant worksheets of the stormwater checklist (C.3 and C.6 Development Review Checklist). See Appendix 1 for step-by-step instructions on completing this checklist.
  2. Review Section 4.2 and select one or more Prescriptive Design Measures you will use to meet the Peak Flow and Volume Control Requirements. Follow the instructions on the Prescriptive Design Measure Fact Sheet to size and design the measure(s).
  3. Prepare a Drainage Plan for your project using the Table 4-2. Prescriptive Drainage 4 Review Drainage Plan Checklist for guidance.
  4. Submit your completed Plan, stormwater checklist, and signed Prescriptive Design Measure Fact Sheet(s) to the County of San Mateo Planning and Building Department.

Prescriptive Sizing Guidelines

Section 4.2 , p27:

  • Landscaped Area
  • Rain Garden
  • Dry Well
  • Planter Box
  • Pervious Pavement

APPENDIX: Kitchen Remodel

There could be fine print around approaching a kitchen remodel as per pages below.

Cross Reference: Document from San Mateo County Planning RE: Kitchen or Bath Remodel Permit

An important factor here is fine print around hard wired smoke and CO detectors. This would get carried into the mix with any electrical work to house interior done under permits.

Reference these details in Planning and Building content called out below.

APPENDIX: Non-conforming Structures

  • SECTION 6135. NON-CONFORMING STRUCTURES / Major Repair, Remodel or Upgrade of Non-Conforming Structures / 6135-5.a.

For a planning and building scenario that would involve the Garage - from County marked as non-conforming due to setback - there would be a need to verify that a Non Conforming Use Permit is even needed against the actual wording in 6135-5.a.

The applicable regulations to reference are 6408.1, 6411(e) and 6135-5.a . To restate differently - it appears the 6135-5.a establishes an acceptable tolerance that we are inside so permissible.

On p56 under regulation 6135-5.a, the violation in question at 5.75ft is not the required 10ft - the garage set back is out of compliance by just 4.25ft. That violation at 4.25ft does not exceed an allowable violation of 50% or 10/2 = 5ft.

The math and exact numbers for this specific garage East side non-conformance against 6135-5.a and wording are key. From Kanoa Kelley, 20240717 email:

“Major repair can be done on sites with structures with non-conforming setbacks. If the encroachment of the setback is 50% or less of the requirement you can still do a major repair without bringing everything into compliance. But again the new construction needs to conform to current setbacks and the only way around this is a non-conforming use permit.”

APPENDIX: ACCESSORY BUIDINGS

Detached Accessory Buildings

Sections: 6409, 6410 and 6411 (pp 22.9, 22.10)

  • Accessory Building Setbacks:

The Zoning Regulations document at this link is relevant, sections 6409, 6410 and 6411, pages 22.9, 22.10. https://www.smcgov.org/planning/zoning-regulations

  • Key point is the 3 feet from property line, notable for North side set back.
  • These “detached accessory buildings” rules have special language around corner lots. Aligning to NW corner of house and that 5 feet set back should avoid issues.
  • The house is correctly set back from West at 5 feet, so if that line is used, the 3 feet is more relevant to North side as per 6410. The regulation under 6409 states that if not attached, would need to be no closer than 5 feet to main building.
  • The distance as per Site Survey from North house edge to property line is 23,65 feet. That determines a maximum North-South dimension for shed or ADU to 15,65.

https://www.smcgov.org/planning/how-do-i-build-accessory-building

  • Accessory Building Height Regulations:

The Division 7 Building Regulations, Ordinance 4873 document at the link below is relevant - reference the text excerpt below. https://www.smcgov.org/planning/county-division-vii-building-regulations

NOTE Section 9007. Work Exempt From Permit, p12.

… no building permit is required for the construction of a one-story detached accessory structure used as tool and storage sheds, playhouses and similar uses, provided the floor area does not exceed 120 square feet, and the height above grade does not exceed 12 feet. No more than one structure may be allowed under this exemption unless separated from another permit exempt structure by more than 50 feet…

ADU

The ADU regulations for CZ are in document - CHAPTER 22.5.1. Accessory Dwelling Units Coastal Zone - notable ones around page 22.5.1.9 in section Section 6439.6 Standards For Detached Accessory Dwelling Units

Reference: https://www.smcgov.org/planning/accessory-dwelling-unit-ordinance

As far as setbacks, see page 22.5.1.3 in Section 6439.5 Development Standards For All Accessory Dwelling Units.

Reference: https://www.smcgov.org/planning/accessory-dwelling-unit-ordinance