Alum Rock, CA land: flood, zoning and parcels
2,484 parcels
0% of Alum Rock’s 2,484 parcels are in a FEMA flood zone.
Map data Oct 11, 2026
- Acres on the roll432
- In a FEMA flood zone0%special flood hazard area
California 2026-27 taxes: bills go out by November 1; first installment due by December 10, 2026, second by April 12, 2027. Pay or check a bill at the Santa Clara County Department of Tax and Collections.
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Around Alum Rock
Flood zones and wetlands
People and new homes in Alum Rock
About 10,440 people live in Alum Rock.
- Population10,4402020–2024 average, ±1,158
- Median household income$126,7052020–2024 average, ±$23,062
Typical lot sizeThe typical lot, from the roll
The median parcel in Alum Rock is 0.16 acre (2,484 parcels with a size).
Acres from the county roll, or from the parcel's own outline where the roll's figure is off by more than three times. Condominium units that share one point (each carrying the whole complex's acres) are left out of the lot sizes.
How Alum Rock is zonedThe most common districts
| Zoning district | Parcels | Share of zoned |
|---|---|---|
| R1 | 2,143 | 86% |
| R1-10 | 198 | 8% |
| R1-6 | 87 | 3.5% |
| R2 | 22 | 0.9% |
| R1-d | 17 | 0.7% |
| CN | 8 | 0.3% |
| R3 | 5 | 0.2% |
| CG | 2 | 0.1% |
Zoning is on file for 100% of parcels in Alum Rock, across 10 districts (the newest zoning map is dated Jul 2023; each parcel page gives its own map's date). A district shown by its code alone has no published name on our map. The town or county zoning office has the final word on any parcel.
Nearby townsTowns around it
Questions about Alum Rock landAnswers from the public records
How many parcels are in Alum Rock, CA?
2,484 parcels on the Santa Clara County tax roll (as of Oct 2026) inside the Census Bureau's boundary for Alum Rock, which can differ from its own limits at the edges, covering 432 acres.
How much vacant land is in Alum Rock, CA?
Santa Clara County's tax roll codes little or no vacant land, so we do not count it here.
What is the typical lot size in Alum Rock?
The median parcel is 0.16 acre, from 2,484 parcels with a recorded size.
How much of Alum Rock is in a flood zone?
0% of parcels are in a FEMA special flood hazard area (National Flood Hazard Layer, as of Oct 2026). Check each parcel's own flood line before you buy.
Are there wetlands in Alum Rock?
0.4% of parcels are a quarter or more wetland on the USFWS National Wetlands Inventory, a mapping guide, not a legal delineation.
What is Alum Rock zoned?
Zoning is on file for 100% of parcels (zoning maps as of Jul 2023). The most common districts: R1, R1-10, R1-6.
Are there land prices for Alum Rock?
No land-price range is shown for Alum Rock yet. We have no sale-price file for Santa Clara County yet.
How many people live in Alum Rock?
About 10,440 on average over 2020–2024 (Census American Community Survey 5-year).
Where does this data come from?
Parcels: County of Santa Clara. Flood: FEMA National Flood Hazard Layer. Wetlands: USFWS National Wetlands Inventory. Towns: U.S. Census places. Every figure is counted from those files on our map.
More in Santa Clara CountyIts other towns
Sources & methodSources, dates and how these figures are built
Headline figures: source and date
Acres on the roll: County tax roll, counted on our map built Oct 11, 2026.
In a FEMA flood zone: FEMA National Flood Hazard Layer, as of Oct 10, 2026; counted on our map built Oct 11, 2026.
Property tax due dates
California Revenue and Taxation Code 2617, 2618, 2619 and 1603; the State Board of Equalization’s 2026 appeal filing periods. Checked Oct 13, 2026.
Flood zones and wetlands: source and date
FEMA flood zone (A or V): FEMA National Flood Hazard Layer, as of Oct 10, 2026; counted on our map built Oct 11, 2026.
Parcels at least 25% wetland: USFWS National Wetlands Inventory, as of Oct 9, 2026; counted on our map built Oct 11, 2026.
People and new homes in Alum Rock
U.S. Census Bureau, American Community Survey 2020-2024 5-year (B19013) (Jan 2026).
Sources
Parcels: County of Santa Clara (roll as of Oct 2026); flood: FEMA National Flood Hazard Layer (as of Oct 2026); wetlands: USFWS National Wetlands Inventory (as of Oct 2026); town limits: U.S. Census Bureau TIGER/Line places; counted on our map built Oct 2026.