Blog > South San Francisco Neighborhoods by Their Lots: Lot Sizes, Flood Zones and Fire Zones
South San Francisco Neighborhoods by Their Lots: Lot Sizes, Flood Zones and Fire Zones
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South San Francisco’s public parcel and zoning records give the zoning and an outline for every parcel in the city. We took the 10,194 lots zoned RL-8, the city’s low-density residential district, 1,500 square feet or more, measured each from its outline, placed it in our neighborhood guide outlines, checked its center against FEMA’s flood map and checked each lot against CAL FIRE’s fire hazard severity zone maps. This post is about the land: lot sizes, flood zones and fire zones. Homes on other zoning, including the downtown residential districts, aren’t counted. The figures come from City of South San Francisco parcel and zoning records, October 2026. There are no addresses or owner details here.
The short answer
- Citywide, the median RL-8 lot is 4,980 sq ft.
- Largest lots: Serra Highlands & Buri Buri (5,190 sq ft), Sign Hill & Parkway (5,180 sq ft) and Westborough & West Park (5,170 sq ft).
- Smallest: Sunshine Gardens (4,570 sq ft), Orange Park & Mayfair Village (4,630 sq ft) and Avalon, Brentwood & Southwood (4,800 sq ft).
- Flood zones: 59 of the 10,194 lots (1%) have their parcel center in a FEMA high-risk flood zone (57 in AH and 2 in AE); 58 of them in Orange Park & Mayfair Village.
- Fire zones: 728 lots (7%) are at least partly in a CAL FIRE fire hazard severity zone: all Moderate; none are High or Very High. All of them are in Paradise Valley & Terrabay (539) and Sunshine Gardens (189).
Next steps in South San Francisco
- What’s my South San Francisco home worth? Request an estimate, and ask us for the recent sales on your street.
- See South San Francisco homes for sale, then use Save Search to get new listings by email.
- Book a strategy call with a Property Nerd.
Neighborhood by neighborhood
Largest median lot first. “RL-8 lots” counts lots zoned RL-8, 1,500 square feet or more, whose center falls inside each guide’s outline; no lot falls in two guides. Each name opens its guide. Downtown South San Francisco is left out: most of its parcels are in the downtown zoning districts rather than RL-8 (it has 32 RL-8 lots), so an RL-8 count says little about it.
| Neighborhood | RL-8 lots | Median lot | In FEMA high-risk zones | In a fire hazard zone |
|---|---|---|---|---|
| Serra Highlands & Buri Buri | 2,121 | 5,190 sq ft | — | — |
| Sign Hill & Parkway | 766 | 5,180 sq ft | — | — |
| Westborough & West Park | 1,262 | 5,170 sq ft | — | — |
| Paradise Valley & Terrabay | 1,348 | 4,910 sq ft | — | 539 |
| Winston Manor | 1,230 | 4,890 sq ft | — | — |
| Avalon, Brentwood & Southwood | 1,752 | 4,800 sq ft | — | — |
| Orange Park & Mayfair Village | 530 | 4,630 sq ft | 58 | — |
| Sunshine Gardens | 1,153 | 4,570 sq ft | — | 189 |
| All of South San Francisco | 10,194 | 4,980 sq ft | 59 | 728 |
The “All of South San Francisco” row also counts the 32 RL-8 lots in Downtown South San Francisco.
What stands out
- Median lots run from 4,570 sq ft to 5,190 sq ft: smallest in Sunshine Gardens, largest in Serra Highlands & Buri Buri.
- Most fire-zone lots are in Paradise Valley & Terrabay: 539 of its 1,348 lots (40%) touch one.
- Most flood-zone lots are in Orange Park & Mayfair Village: 58 of its 530 lots (11%), in zones AH and AE.
Flood zones, neighborhood by neighborhood
RL-8 lots in FEMA high-risk zones inside each guide’s outline, the share of the guide’s lots they make up, and the zones; most first. The other seven guides have none.
| Neighborhood | High-risk lots | Share of the guide’s lots | Zones |
|---|---|---|---|
| Orange Park & Mayfair Village | 58 | 11% | AH 57, AE 1 |
| All of South San Francisco | 59 | 1% | AH 57, AE 2 |
What the flood zones mean
- Zone AE: a 1%-a-year chance of flooding, with a base flood elevation set.
- Zone AH: shallow ponding, usually 1 to 3 feet deep, with the same 1%-a-year risk and a base flood elevation.
- Zone X: moderate to minimal risk, outside the 1%-a-year floodplain.
- Insurance: if the house itself is in an A or V zone, lenders on federally backed mortgages require flood insurance; a flood zone determination for the address settles it. In zone X it’s optional.
Fire hazard zones, neighborhood by neighborhood
CAL FIRE maps how severe the wildfire hazard is across California, in three classes: Moderate, High and Very High. RL-8 lots inside each guide’s outline, by the highest zone that touches any part of the lot; most severe first. No lot touches a High or Very High zone. The other six guides have none in any zone.
| Neighborhood | RL-8 lots | Moderate | Not in a zone |
|---|---|---|---|
| Paradise Valley & Terrabay | 1,348 | 539 | 809 |
| Sunshine Gardens | 1,153 | 189 | 964 |
| All of South San Francisco | 10,194 | 728 | 9,466 |
What the fire zones mean
- Hazard, not risk. CAL FIRE’s Office of the State Fire Marshal says the maps describe hazard: the physical conditions, like vegetation, terrain, fire history, embers and typical fire weather, over 30 to 50 years. They don’t count home hardening, defensible space or fuel reduction, which change the risk to a particular home (OSFM).
- Two kinds of map. Inside city limits (Local Responsibility Areas) we used CAL FIRE’s 2025 map; where the state is responsible for wildfire protection (State Responsibility Areas), its State Responsibility Area map. Land outside the three classes is shown as non-wildland or unzoned (OSFM).
- What a zone can bring. Depending on the zone and the kind of area, stricter building standards for new construction and additions, defensible-space rules, and a line on the seller’s natural hazard disclosure. The city’s building department can say which apply.
Reading it right
- Zoning isn’t use. We counted lots zoned RL-8, 1,500 square feet or more. A lot’s zoning doesn’t say what’s built on it, and homes on other zoning aren’t counted.
- Lot sizes are measured from the city’s parcel outlines, so they can differ from a survey by a few percent.
- We checked the center of each lot against FEMA’s National Flood Hazard Layer. A lot can straddle two zones, and maps change, so check the current FEMA map for the exact address.
- The flood zone covers the land, not the house. A house can sit above the base flood elevation even in a high-risk zone. An elevation certificate settles it and can lower the insurance price.
- The fire zone describes the land around a house, not how the house is built or how the lot is kept. CAL FIRE’s zone viewer shows any parcel, and a seller’s natural hazard disclosure report states the zones for that property.
- A median isn’t a verdict. It describes the lots, not which neighborhood is right for you.
Go deeper
South San Francisco Housing Market by the Numbers covers prices and bidding, South San Francisco Neighborhoods Ranked by Price per Square Foot compares the neighborhoods on price, and The Most Expensive Streets in South San Francisco goes street by street. Flood & Fire Zones by Neighborhood compares every guide we write, and the South San Francisco city guide links every neighborhood guide.
The South San Francisco data series: housing market by the numbers · neighborhoods ranked by price per sq ft · where homes sell over asking · ten years of prices by neighborhood · condos and townhomes · house prices by bedrooms · houses under $1.2M · houses at $1.6M and up · the best month to sell · the most expensive streets
Buying, selling or rebuilding in a flood or fire zone?
A Property Nerd can pull the zoning, the lot, the flood and fire zones, any elevation certificate and the recent sales on your street before you write an offer, set a price or plan a rebuild. Call (408) 373-1660 or (650) 383-8606, or book a strategy call. Commissions are negotiable, and we offer bundled services, so ask us what’s included.