Fremont | Hill area and historic review

Fremont, California Hill Area and Historic Review: The Toe of the Hill Line, Open Space Lots, the Hillside District, Grading, Fire Zones and Historic Screening

Two sets of Fremont rules can block or change a housing project before the zoning tables apply. The first covers the hill areas of the city. Two initiatives apply there, which the code names as the "Hillside Initiative of 1981 (Measure A) and the Hill Area Initiative of 2002 (Measure T)," and the zoning title carries them out through the open space district and the hillside combining district. The second set covers old buildings: a historic screening before any building 50 years old or older is demolished, and review by a City board in the historical overlay districts. This page covers both. The Fremont overview has the summary.

The Three Hill Areas

The definitions chapter says the hill area shown on the General Plan "consists of three distinct hill areas":

• "The hill area located above the toe of the hill line, subject to the provisions of the Hill Area Initiative of 2002."
• "The hill area located below the toe of the hill line but within the area affected by the Hillside Initiative of 1981. This area is generally located easterly of Mission Boulevard and I-680."
• "The other hill areas not included" in the first two, which "are generally located between the northern and southern crossings of Mission Boulevard and I-680 as well as the Coyote Hills area."

An initiative is a law that begins as a petition signed by voters. The zoning title refers to the 2002 initiative in many sections and gives it priority. In a planned district, for example, "in cases where there are conflicts with regulations implementing the Hill Area Initiative of 2002, the regulations implementing the Initiative shall apply." This guide read the zoning sections that carry out the two initiatives. The initiative texts were not read.

The Toe of the Hill Line

The line that separates the strictest rules from the rest is the toe of the hill. The code defines it as "a line along the base of the hills along which the natural grade first becomes 20 percent or more, as defined by slope analysis." The definition places it on the western side of the hill area, from the boundary with Union City to the boundary of Alameda and Santa Clara counties, "and on both sides of Niles Canyon and Interstate 680 east of Mission Boulevard to the Fremont city limits." A grade of 20 percent rises 20 feet over 100 feet of distance.

• A continuous line. "The toe of the hill shall be a continuous line," and the slope is "measured perpendicular to elevation contours as established from a survey of the natural topography."
• Graded land. Natural grade means land not altered by people, or land whose grading "was approved prior to the adoption of the Hill Area Initiative of 2002."
• Small pockets. Where the 20 percent line forms pockets or projections narrower than 125 feet, the line is drawn straight across them.
• Moving the line on a property. An owner may apply to the Planning Manager "to more precisely locate the toe of the hill line on any property concurrent with a development application," with a survey by a licensed land surveyor or civil engineer.
• How far. "A general plan amendment and zoning map amendment (approved by the city council) are required to implement any change that results in the movement of the toe of the hill line by more than 50 feet." Smaller adjustments are shown on the site plan and considered by the body approving the project.

Open Space Land: Lot Sizes

Land above the line that is designated open space is in the O-S open space district. Chapter 18.55 says its intent is "to permit limited but reasonable use of open lands while protecting the public health, safety and welfare from the dangers of seismic hazards and unstable soils." The lot sizes are in acres. One acre is 43,560 square feet.

Source: Fremont Municipal Code, Section 18.55.030, subsection (a).

• Clustering. In the hill and hill face designations, "lot area may be approved at less than this minimum lot size when parcels are clustered through the conditional use permit process to reduce visibility and environmental harm." Clustering groups the homes on one part of the land and leaves the rest open.
• Mixing land types. Constrained and unconstrained land may be combined in one ownership to meet the lot area, "provided, that there is at least one contiguous and accessible acre of unconstrained land per residential dwelling unit."
• Yards. A lot of 10 acres or more needs yards of 50 feet and a width of 300 feet. A lot of more than one acre and less than 10 needs a 45-foot front yard, 35-foot side yards, a 50-foot rear yard and a width of 225 feet.
• Height. "Building height shall not exceed 35 feet within the city park designation and 30 feet in all other open space designations."

Building Above the Toe of the Hill Line

Section 18.55.040(b) lists the standards for "Dwellings, Structures, New Lots and Other Development Located above the Toe of the Hill Line."

• Floor area. "The maximum aggregate floor area for all floors (regardless of composition) in buildings on a parcel of 20 acres or more may not exceed one percent of the parcel's area, or 20,000 square feet, whichever is less, but for any such parcel a minimum of 10,000 square feet shall be permitted." One percent of 20 acres is 8,712 square feet, so the 10,000 square foot minimum applies to a 20-acre parcel (VanPlex arithmetic: 20 times 43,560 times 0.01).
• Development envelope. All buildings on a parcel must sit within one contiguous development envelope "not to exceed two acres," except buildings that must be elsewhere for farming, security or public utilities.
• Ridgelines and hilltops. "Structures may not be located on ridgelines or hilltops, or where they will project into the visual plane of a ridgeline or hilltop, as viewed from public roads, trails, or other public places, unless there is no other building site on the parcel or on a contiguous parcel in common ownership."
• New parcels. "Unless there is no other possible configuration, new parcels may not be created that have no building site other than a ridgeline or hilltop."
• Streams. "No development shall be located within a riparian corridor," defined as "the areas within 200 feet from the center of a permanent or intermittent streambed," with exceptions for flood control, roads, fences and trails.
• Constrained land. "No building site, in whole or in part, may be located on constrained land."
• Easement. An easement to the City "shall be required for each parcel with respect to which development is permitted." It bars further development the title would not allow. "The easement shall be negative only; it shall convey no possessory interest to the city or its designee, nor confer any right of public access."
• Lot line adjustments. The City may not allow one where the adjusted parcels would not meet the General Plan, "including minimum parcel sizes," or one between more than four parcels.
• Certificates of compliance. "A certificate of compliance by itself creates no right to develop."

Standards for all open space development apply too. "The impervious coverage shall not exceed 15 percent of the area of each lot," where impervious coverage means buildings, paving and other surfaces that water cannot soak through. A design review permit is required before any dwelling is built.

Which Homes Are Allowed on Open Space Land

• Houses. Table 18.55.110 lists "Residential, single-family" as a conditional use on land designated Hill (beyond Ridgeline) and Hill Face, and as a zoning administrator use on General open space and Hillside (Measure A) land.
• ADUs. An accessory dwelling unit and a junior accessory dwelling unit are accessory uses on General, Hill, Hill Face and Hillside (Measure A) land.
• Small existing lots. Section 18.55.060: "Where a lot existed as of January 1, 2002," has no constraints, and "the area of such lot on said date was not less than 4,000 square feet, the planning commission may approve a conditional use permit authorizing the use of the lot for one single-family dwelling." The Commission must find the use "consistent with the Hill Area Initiative of 2002."
• Additions. For a lot above the line already developed with a house, Section 18.55.090 sends additions that keep the primary building at or under 7,500 square feet, and accessory structures up to 600 square feet, to design review by the zoning administrator. Larger ones need Planning Commission approval.
• Lots partly in O-S. Where a lot is partly in O-S and partly in a residential district, the homes that could have been built on the O-S part may be moved to the other part if that part "shall be developed as a planned district" and the O-S part is kept open by easement.
• What an application needs. A contour map, a slope classification map by a civil engineer or land surveyor showing land under 20 percent, 20 to 30 percent and over 30 percent, and "A visual impact analysis prepared by a qualified consultant" for buildings on hill face land or within 300 feet of a hilltop or ridgeline.

The (H-I) Hillside Combining District

Below the open space land, sloping residential lots carry the (H-I) designation, which is added to a base district such as R-1-10. Chapter 18.130 says "where conflict between regulations occurs, the regulations specified in this chapter shall prevail." It cannot be combined with planned districts or open space districts.

Source: Fremont Municipal Code, Section 18.130.040 and Section 18.130.050.

• Constrained land. Section 18.130.030 treats as constraints areas of "Severe soil instability," land the city engineer or building official finds to be "a landslide, in the path of a landslide, at risk of a landslide, or in an area of slope instability," and "Lands having slopes in excess of 30 percent." A site-specific geotechnical report can show that a constraint "is capable of reasonable mitigation."
• Fitting the land. "Structures shall be designed to fit the land, instead of modifying the land to fit the structure."
• Views. "Needless obstructions to view corridors shall be deemed a potential basis for denial."
• More height below the line. The Planning Manager may approve more than 30 feet for property below the toe of the hill line if the increase "would not exceed 15 percent of the total roof area as seen in plan view" and three other findings are made.
• Water and sewer. "Development of legal parcels shall be limited to one dwelling unit per 20 acres until such parcels meet the water and sewer service levels established by the Alameda County water district and the Union sanitary district."
• Colors and materials. "Exterior color schemes shall avoid bright and contrasting colors," and exposed metals must be treated to prevent reflective surfaces.
• How slope is measured. Section 18.130.080 measures natural slope inside a minimum rectangle placed around the building site: 43 by 64 feet in R-1-6, 54 by 64 feet in R-1-8, 60 by 70 feet in R-1-10, 75 by 143 feet in R-1-20 and 105 by 200 feet in R-1-40.

Parcels the Line Crosses

• 20,000 square feet or less, no subdivision. Section 18.130.060: such a parcel "shall be reviewed by planning division staff based upon a checklist to determine if the purposes of the Hill Area Initiative of 2002 are being affected." If they are not, "the project may proceed in accordance with the zoning and other city standards established for the portion of the lot located below the toe of the hill line."
• Larger parcels, no subdivision. "development located above the toe of the hill line shall comply with the provisions of the Hill Area Initiative of 2002, while development located below the toe of the hill line shall comply with the zoning and other city standards applicable to the area below."
• Subdivisions of less than 20 acres. Section 18.130.070: area above the line "shall not count towards the minimum parcel size required by the zoning district below the toe of the hill line," and it "shall be placed in an open space easement" that allows only open wire-style perimeter fencing.
• No moving density uphill. In a planned district, "In no instance, however, may density from below the toe of the hill be transferred to locations above the toe of the hill."

Geotechnical Reports and Grading Permits

A geotechnical report is a study of soil and slope stability by a licensed engineer or geologist. Section 18.90.030 says that in the hill area the city engineer or building official "may require a new or additional on-site geotechnical report for grading plans, subdivision maps, or building permits on lands which are in a landslide area, in the path of a landslide, at risk of a landslide, or in an area of slope instability." The official may also require "peer review by an independent geologist selected by the city engineer or building official with the cost borne by the applicant."

Grading is moving earth to shape a site. Section 18.205.030 requires a permit from the city engineer for, among other things:

• "Grading involving 100 cubic yards or more within a 12-month period."
• "Grading on land with a natural slope of more than four percent that increases or decreases any portion of a site by a height of more than two feet at any point upon completion of grading."
• On flatter land, a change of more than three feet.
• "Clearing of an area greater than10,000 square feet with an average slope equal to or exceeding 10 percent (excluding agricultural grading)."
• "Grading or clearing within 100 feet by horizontal measurement from the top of the bank of a watercourse."

Grading of more than 5,000 cubic yards must be supervised by a registered civil engineer. In the (H-I) district, where a grading permit is needed, an engineer must also certify that the finished grades "do not deviate from the approved plan by more than one foot of vertical elevation." The Master Fee Schedule lists a $600 deposit for plan check of a grading permit outside a subdivision.

Fire Hazard Severity Zones

Chapter 15.65 was replaced by Ordinance 10-2025 on July 15, 2025. The staff report says the state fire agency, CAL FIRE, "released new Fire Hazard Severity Zone (FHSZ) maps for Local Responsibility Areas (LRA) on February 24, 2025," with three classes of zone: moderate, high and very high. The ordinance adopts that map "with amendments retaining additional areas previously classified by the City as Very High fire hazard severity zones."

• City-added zones. Section 15.65.040: the City "designates additional areas beyond those identified by the State Fire Marshal, as very high fire hazard severity zones," areas "previously approved by the city council as very high fire hazard severity zones on December 4, 2007 (Ordinance 33-2007)."
• The map. It is titled "City of Fremont, Local Responsibility Area, Fire Hazard Severity Zones" and dated June 26, 2025. A copy is kept by the City Clerk and posted by the Fire Department.
• Building rules. In the open space district, a structure in a fire hazard severity zone or the wildland-urban interface fire area "shall comply with specific additional requirements set forth in Title 15." Ordinance 12-2025 of September 16, 2025 added a wildland-urban interface code as Chapter 15.66.
• SB 9. The City's SB 9 section bars projects on sites listed in Government Code 65913.4, subdivision (a)(6)(B) to (K). One of them is land "Within a very high fire hazard severity zone," with an exception for "sites that have adopted fire hazard mitigation measures pursuant to existing building standards."

Historic Screening Before Demolition

The second set of rules is in Chapter 18.175, Historic Resources. Its screening rule covers any building that is 50 years old or older on the date of the application. Section 18.175.150: "In order to identify historic resources before their historic integrity is destroyed through demolition or relocation, no permit will be issued for these purposes for a building, structure or object that is 50 years old or older until it has been screened for historic significance."

• First step. The City checks whether a historic resources inventory form already exists. If not, the Planning Manager "may conduct a site visit to perform a visual analysis and/or engage in preliminary research." If the building has no historic significance, the permit is processed.
• If it may be significant. The Planning Manager has an inventory form prepared "by a qualified historic resource professional selected and approved by the city," and "The applicant, through the city, shall pay for the cost of preparing the form."
• Potential register resource. A building found to meet the standards for the California or Fremont register is a potential register resource. Its demolition or relocation "may be reviewed and approved by the board," the Historical Architectural Review Board, while a listed Fremont register resource "shall require recommendation by the board and final action by the city council."
• What demolition means. For a building with no historical significance, "the removal of 50 percent or more of the exterior walls or the roof form."
• The fee. The Master Fee Schedule lists "Historic Evaluation Screening" at a flat $192. Design review by the board has a deposit of $8,000 for a single-family or two-family project and $15,000 for other review.
• Appeals. Only the finding that a building is a potential register resource may be appealed, first to the board and then to the City Council.

Historical Overlay Districts and Objective Standards

Section 18.175.140 describes the (HOD) overlay as "a zoning designation applied by the city council to certain areas within the city of particular historical significance." The code does not list the districts by name in the chapters read. It does name "the Mission San Jose historic overlay district" in the commercial standards, and it describes the town center pedestrian districts as "the historic cores of Centerville, Irvington, Mission San Jose and Niles." Building height in the town center districts is held to 40 feet in Mission San Jose or Niles. The overlay map was not read.

• What needs review. Section 18.135.050: "New buildings, structures and signage," site features, "Any alteration, addition or modification to the exterior of an existing structure or sign," and "Any variance or exception to standard zoning requirements."
• Houses and duplexes. Section 18.135.060: "A single-family or two-family dwelling is not subject to the provisions of this chapter unless" it is a register resource, a potential register resource, "located in a portion of an (HOD) in which the city council-approved guidelines require such review," or in a commercial district.
• Staff-level items. In-kind replacement of windows, doors, siding and roofing, and accessory buildings of 300 square feet or smaller, can be decided by the board secretary.
• The test. A project "shall be compatible with the HOD in terms of siting, massing, scale, size, material, texture and color."
• Objective standards since 2025. The City Council staff report of January 14, 2025 explains that during review of the City's housing plan the state housing department "identified the subjective nature of the City's historic review process, particularly for single family and two-family homes as well as ADUs, as onerous and not being in compliance with State housing laws." The City prepared objective standards for eligible register resources, checklists that "would not apply to listed register resources, nor to projects involving demolition or relocation of listed or register eligible structures." Ordinance 03-2025, passed February 4, 2025, amended Chapter 18.175.
• State housing laws. The SB 9 section bars a two-unit development in "a contributing structure within a historic district" or on a listed landmark or historic property, and the small-scale multifamily section does not apply in a historic district.

Where the Code Differs From Itself

• 30 feet or 35 feet. Section 18.55.020 limits buildings in the hill open space designations to 30 feet. Section 18.250.040 says "the visual safeguards section of the Hill Area Initiative of 2002 limits the overall height of buildings to no more than 35 feet when buildings are located above the toe of the hill line." The lower figure, 30 feet, is the zoning limit.
• Which standards control. Section 18.130.050 says that in a conflict within the hill area "the performance standards in the open space regulations shall prevail" over the hillside district standards. Section 18.130.020 says the hillside chapter prevails over the base district.
• Fire zone dates. Section 18.55.040 refers to fire zones "as set forth in Section 15.65.030." Chapter 15.65 was replaced in July 2025, and the City-designated zones are now in Section 15.65.040.
• Slope rectangles. Section 18.130.080 gives a rectangle for an R-1-80 district. Table 18.90.040 has no R-1-80 column.

Limits of This Page

The code text is the publisher's copy, current through Ordinance 02-2026 of May 5, 2026. The City website answered 403 to a script. The following were not read: the texts of the 1981 and 2002 initiatives, the General Plan and its hill area maps, the zoning map and the location of the toe of the hill line, the hillside street standards, the City's hill area checklist, the fire hazard severity zone map, the historical overlay district map and guidelines, the Fremont register of historic resources, and the objective standards for eligible register resources. This page cannot say whether a lot is above the line, in the (H-I) district, in a fire zone or in a historical overlay district. Earthquake fault zones and flood zones are not covered. Ask the Planning Division, the Engineering Division and the Fire Department about a specific lot.

Where to Go Next

Related on VanPlex: the Fremont overview, the zoning districts page and the California property tax and insurance page.

Frequently Asked Questions

Official sources (checked October 2026)