San Mateo | Measure T and Height Limits

San Mateo, California Measure T and Height Limits: Measures H, P and Y, General Plan 2040 Table LU-1, Who Approves Tall Buildings and the 2031 End Date

In San Mateo the voters, through ballot measures, have set the top limits on building height and homes per acre since 1991. The current measure is Measure T, approved on November 5, 2024. It replaced a citywide limit of 55 feet and 50 units per acre with a table in the General Plan that allows up to eight stories and 130 homes per acre in ten study areas, and it keeps that table under voter control until 2031. This page explains the measure, the table, and what they mean for a project. The San Mateo overview has the summary.

From Measure H to Measure T

The recitals of Ordinance No. 2024-10, the opening statements of the ordinance, give the sequence of measures. On November 3, 2020 "the voters of the City of San Mateo approved Measure Y, which extended through 2030 certain General Plan policies enacted by Measure P in 2004, which in turn amended and extended the 1991 voter initiative Measure H." The Land Use Element of the General Plan states what those policies were: "the Measure Y height limit is set to 55 feet and three to five stories, the density limit allows up to 50 units per acre and the nonresidential intensity allows up to a 3.0 floor area ratio (FAR)."

Sources: City of San Mateo, Ordinance No. 2024-10, recitals and Sections 9 and 12; Ordinance No. 2025-04, recitals and Section 6.

The Council adopted General Plan 2040 on March 18, 2024, while Measure Y was still in force. The plan included designations above the Measure Y limits and said "Any components in the General Plan that are inconsistent with Measure Y will require voter approval before they can take effect." The recitals of Ordinance No. 2024-10 say "under state law, any change to Measure Y is subject to voter approval," so the Council placed the Land Use Element on the ballot. The measure passed "by a vote of 59% (25,271 votes) to 41% (17,283 votes)."

What Measure T Says

• The Land Use Element is approved. Section 1 approves the Land Use Element and adds that it "may be modified without voter approval through the general plan amendment process," with one exception: "voter approval shall be required to modify the density ranges, intensity or FAR, or building heights that correspond to each designation in Table LU-1 (Land Use Designations)."
• No higher designation. "New land use designations may be created, but no new land use designations may be authorized with density ranges, intensity or FAR, or building heights greater than those set forth in Table LU-1."
• Changing a parcel's designation. The designation of a parcel may be changed by a general plan amendment "provided that no increase in allowed density, intensity, or FAR shall be permitted on that parcel without voter approval." Section 5 lists eight locations that may move to a named higher designation without a vote, among them 50 Mounds Road and 1770 S. Amphlett Blvd.
• The rest of the city. Appendix A "is a map that identifies those areas of the City of San Mateo that will maintain the height, density, and intensity restrictions of Measure Y." The recitals say the measure keeps those limits "except for ten study areas where growth would remain restricted but subject to higher height, density, and intensity limits than Measure Y."
• Measure Y is repealed. "Measure Y, attached hereto as Attachment 3 and incorporated by reference, is hereby repealed in its entirety."
• End date. "The provisions of this ordinance shall remain in effect until amended by the voters, or until January 1 2031, whichever comes first. Beginning on January 1, 2031, any provision of the General Plan approved by the voters may be amended in accordance with the City Charter and state law without voter approval."
• Takings. If applying the measure to a property would be a taking of private property, "the City Council may allow additional density or uses on said property," limited to "the minimum necessary to avoid a taking."

The recitals also say where the growth is meant to go: the measure "would maintain existing heights and densities on residential neighborhoods, with a focus on planning for new development in the downtown, near Caltrain stations, and along transit corridors."

Table LU-1: Density and Height by Designation

A General Plan land use designation is the category the plan's map gives a parcel. It is separate from the zoning district. Table LU-1 gives each designation a density range in dwelling units per acre, a height in stories, and for nonresidential uses a floor area ratio. Floor area ratio, or FAR, is building floor area divided by lot area.

Source: City of San Mateo, General Plan 2040, Land Use Element, Table LU-1 (file dated March 18, 2024, plan pages 42 to 44), read from the page images. Service Commercial/Light Industrial, Parks and Open Space, Public Facilities, Utilities and Transportation Corridor allow no homes and are left out.

• A range, with no minimum. A note under the table says it "establishes the maximum allowed density range for this land use designation, with associated Zoning district setting a maximum density within this range; but this range does not set a minimum required density."
• No guarantee. "The maximum density assigned to each land use designation does not constitute entitlement, nor are property owners or developers guaranteed that an individual project, when tested against the General Plan's policies, will be able or permitted to achieve these maximums."
• The zoning still applies. "Each project must also comply with the specific rules of the relevant zoning district in the City's Zoning Code."
• Exceeding the limits. Describing the earlier limits, the element notes that "State Density Bonus law allows projects to exceed these limits when certain percentages of affordable units are provided."
• House neighborhoods. Residential Very Low allows "detached single-family homes, detached townhouses and duplexes, and accessory dwelling units (ADUs)" at up to 9 homes per acre and 1 to 3 stories. An R1 house is also held to the Zoning Code limit of 24 feet to the plate line, the girder line that supports the roof framing, and 32 feet to the roof.

How the Zoning Code Follows the Table

The Zoning Code was written around the older limits, and most of it has not been rewritten. On April 7, 2025 the Council adopted Ordinance No. 2025-04, which added Section 27.02.220. It says Measure T "allows for the full implementation of the Land Use Element in General Plan 2040," and that in a conflict "the uses, densities, intensities and heights specified in Table LU-1 (Land Use Designations) in the Land Use Element and associated with the Land Use Map shall control." The ordinance passed with five votes in favor and none against.

In practice a lot has two classifications. Its zoning district gives yards, parking, open space and the review steps. Its General Plan designation gives the top density and the height in stories. The R3, R4 and R5 chapters each say "Building height shall not exceed the standards set forth on the Building Height Plan of the General Plan," so they already rely on the General Plan for height. For density, the R3 to R5 tables stop at one home per 870 square feet of parcel, which is 50 homes per acre, and the General Plan number applies where it is higher.

The General Plan gives heights in stories, and the Zoning Code works in feet. The City's staff report of September 8, 2026 shows the conversion used for the four new districts: "a formula that used 14 feet for the first floor and 12 feet per floor for each upper story level." By VanPlex arithmetic that is 74 feet for six stories and 98 feet for eight, and the draft districts round to 75 and 100 feet. The report says "these proposed height limits are considered interim standards." The districts are covered on the zoning districts page.

Who Approves a Tall Building, and the 55-Foot Text Still in the Code

After Measure T the Council changed the rule on who approves tall buildings, and the change reached some sections and missed others. The table shows the five places the code speaks to it.

Source: San Mateo Zoning Code, 27.04.130, 27.06.040, 27.06.050, 27.08.030 and 27.40.020; Ordinance No. 2025-05, Sections 3 and 4.

City documents show how this happened. Ordinance No. 2025-05, adopted July 28, 2025, printed the new review text under the heading of Section 27.04.130, a definition, in place of Section 27.08.030. The code copy now shows the review rules where the definition of "community care facility" used to be, and Section 27.08.030 keeps the 55-foot sentence. The staff report of September 8, 2026 says the provisions "were inadvertently placed within the Zoning Code's definitions section, resulting in the removal of the existing definition," and that the 55-foot language "is now inconsistent with other more recently amended sections of the Zoning Code, so it is proposed to be removed." The report names Ordinance No. 2025-03 as the source; the City's ordinance library shows the text in Ordinance No. 2025-05.

The correction is in the ordinance on the Council agenda of September 22, 2026. The minutes of that meeting were not posted when this guide was written, so this page does not state that it was adopted. Until the code is corrected, a project between 55 feet and the General Plan height should confirm its review body with the Planning Division. The code also defines a "High-rise building" as "any building which is more than 50 feet in height as measured from average grade," a term the downtown and R5 chapters use.

Downtown Height and Bulk

Chapter 27.40 applies inside the Downtown Specific Plan area. Buildings may be built "provided they do not exceed the maximum height delineated for the respective project sites as shown on the Building Height and Bulk Plan in the Downtown Specific Plan." Above 55 feet the chapter limits the size of each floor to a "maximum building dimension of 150 lineal feet and maximum diagonal dimension of 170 lineal feet," and its table stops at 75 feet. On parcels in the Street Wall Area, Chapter 27.42 limits height at the street edge to the distance from the middle of the street to the parcel line "or thirty-six (36) ft., whichever is greater," with upper floors set back under a 45-degree line.

The history notes of these chapters cite ordinances of 1986, 1987 and 1992. Both chapters point to the Downtown Specific Plan, which this guide did not read. Where they conflict with Table LU-1, Section 27.02.220 gives the answer for height: the table controls. The bulk and street wall rules are a separate subject that Table LU-1 does not cover.

Measure T and State Law

• SB 79. The 2025 state transit law sets the lowest height limits a city may impose near major transit stops. The City's SB 79 FAQs list 95, 75 and 65 feet by distance from the three Caltrain stations and say the state standards "apply and supersede any conflicting local zoning regulations." Government Code 65912.157 words the 75-foot rule this way: "A local government shall not impose any height limit less than 75 feet."
• No alternative plan. SB 79 lets a city adopt its own plan that shifts capacity among sites. The FAQs say: "Due to the limitations imposed by Measure T, approved by the San Mato voters in 2024, adopting an Alternative TOD Plan to reallocate housing capacity to other areas is not feasible for the City without voter approval."
• Density bonus. The state density bonus law applies in San Mateo through Chapter 27.15, and the Land Use Element itself notes that it lets projects exceed the voter limits.
• Charter city. San Mateo has a City Charter, and Measure T refers to "the general plan amendment process set forth in the City Charter and state law." SB 9 and the ADU statutes each define a local agency as a city "whether general law or chartered."

The housing numbers behind the measure are in the recitals of Ordinance No. 2025-04. The Housing Element "plans for a total of 10,286 units, over and above the RHNA allocation of 7,015 units for the eight-year planning period of 2023-2031." RHNA is the regional housing needs allocation, the number of homes the state assigns a city to plan for. "The approval of Measure T increases the capacity of the Sites Inventory in the Housing Element from 10,286 units to approximately 20,000 units," and beyond those sites it "expands the development capacity within the City by approximately an additional 10,000 units, for an approximate total of over 30,000 units of housing."

Where the Documents Differ

• Mixed-Use Medium II. Table LU-1 prints 51 to 99 homes per acre. Table 5 of Measure T, in the entry for 1495 S. El Camino Real, describes the same designation as "4 to 6 stories, 51 to 90 du/ac." The staff report of September 2026 uses 99.
• The environmental report total. Ordinance No. 2025-03 says the General Plan environmental impact report "analyzed new residential development of up to 19,764 new housing units." The draft ordinance of September 2026 says it analyzed "up to 21,410 new housing units," while the staff report for the same item says 19,764.
• The height map. The City's Planning Maps page still posts a Building Height Plan dated September 2024 that it describes as the limits "while Measure Y is in effect." The Land Use Map on the same page is dated March 2025.
• Policy LU 1.9. The posted Land Use Element file, dated March 18, 2024, still says inconsistencies "shall default to the provisions specified in Measure Y." Measure T has since repealed Measure Y.
• The 55-foot sections. See the table above.

Limits of This Page

Measure T was read from the City's ordinance library, which prints the ordinance text and marks its four attachments "See PDF." Those attachments, the Land Use Map, Appendix A and the map of the ten study areas were not read. Table LU-1 was read from the Land Use Element file dated March 18, 2024 on the City's General Plan site, which is the version the Council adopted before the vote. This guide cannot say which designation covers a lot, or whether a lot is inside a study area. The Downtown Specific Plan and its height plan were not read. Ask the Planning Division for the designation, height limit and density range of your lot, and whether the code sections on 55 feet have been corrected.

Where to Go Next

Related on VanPlex: the San Mateo overview, the California SB 79 page and the permits and fees page.

Frequently Asked Questions

Official sources (checked October 2026)