256 Sweeny St

San Francisco · Portola · Block/lot 5859/012 · San Francisco

Property brief (PDF)Timeline ↓Calculator ↓Official records ↓

What's changing nearby

Since October 2024 within ½ mile: 15 homes completed, 9 permitted, 9 proposed or in review.

21 projects with a record in this window, grouped by us from permits and State housing reports. Units are as proposed on each project's latest record and counted at its current stage.

663 permits within ½ mile since October 2024

Adds housing (ADU)9 · 19 units
Demolition2
Additions & renovations185
Building systems357
Repairs34
Other76

The map shows new construction, ADUs, demolitions, additions, and renovations. Routine systems work (roofs, HVAC, water heaters) is counted but not mapped. Unit counts are as stated on permits.

Explore projects on the map →Explore sales & prices →

Source: San Francisco Department of Building Inspection, Building Permits · Geography: permits located by parcel, ½ mile radius · Retrieved Oct 29, 2026

Estimated price, listing status & sales records

Benchmark valuation & transaction history

Estimated PriceArea benchmark

$1,462,000

Benchmark range: $1,243,000 – $1,681,000

Listing StatusOff Market

Not currently listed for sale

Compare nearby sales & prices on map →

Last Sold & Tax Roll

No deed price in open GIS feed

Verify on Property Information Map

How this estimated price is calculated (Area ZHVI + ACS + Permit Benchmark)

Model monthly ownership cost ↓

1. Area home value baseline: Portola Census ACS 5-year median home value ($1,211,948); $1,211,948
2. Parcel & lot adjustment (1.00×): Standard residential parcel (1.00× area baseline); +$0
3. Documented permitted improvements: +$249,600 from documented permits (1 ADU); +$249,600

Public-records benchmark estimate combining Zillow Home Value Index (Data provided by Zillow), Census ACS 5-year estimates, parcel land-use/lot characteristics, and issued building permits. Not an official appraisal.

What could be built here

A screen, not a determination

ADU or junior ADU

Likely eligible

Zoned RH-1 (single-family residential): state law allows ADUs where homes are allowed.

What we couldn't check (4)

Setbacks, height and size limits in the local ADU ordinance
Utility and sewer capacity, fire access
Historic district or landmark status: we have no historic layer for this area yet.
Locally adopted fire hazard maps, which can be broader than the State's.

SB 9: two homes on the lot

Likely eligible

Zoned RH-1, a single-family residential zone.

What we couldn't check (6)

Whether a tenant lived there in the last 3 years, or the building was withdrawn from rent under the Ellis Act
Rent-controlled or deed-restricted affordable housing on the lot
Wetlands, habitat, farmland, hazardous waste sites and conservation easements
Local SB 9 standards (size, setbacks, parking)
Historic district or landmark status: we have no historic layer for this area yet.
Locally adopted fire hazard maps, which can be broader than the State's.

SB 9: split into two lots

Unlikely

Zoned RH-1, a single-family residential zone.
The lot is 1,875 sq ft on the parcel map; a split needs at least 2,400 sq ft (two lots of 1,200 sq ft or more).

What we couldn't check (6)

Owner-occupancy: the applicant must sign an affidavit to live in one of the homes for 3 years
Whether the lot was created by an earlier SB 9 split, or the owner split an adjacent lot
Whether a tenant lived there in the last 3 years, or the building was withdrawn from rent under the Ellis Act
Wetlands, habitat, farmland, hazardous waste sites and conservation easements
Historic district or landmark status: we have no historic layer for this area yet.
Locally adopted fire hazard maps, which can be broader than the State's.

Mapped hazards on this lot

Fire hazard severity zone: Not in a State-mapped zone
FEMA flood zone: Zone X: minimal flood hazardFIRM panel 0602980231A, effective March 23, 2021. Official flood map
Earthquake fault zone: Not in an Alquist-Priolo Earthquake Fault Zone

Built nearby: within ¼ mile since October 2023

Accessory dwelling unit (new or conversion)6

See them on the map →

Permit counts, by the date issued (or applied, if not yet issued). Lot splits are planning cases, which we don't have.

We read public zoning and hazard maps against state law (ADUs: Gov. Code 66314; SB 9: Gov. Code 65852.21 and 66411.7). Local rules, title, tenancy history and site conditions can change the answer. Check with San Francisco's planning department before relying on it.

Sources: San Francisco Planning, Zoning Map – Zoning Districts (retrieved Oct 29, 2026) · CAL FIRE Office of the State Fire Marshal, Fire Hazard Severity Zones in the State Responsibility Area (effective 2024-04-01) (retrieved Oct 26, 2026) · CAL FIRE Office of the State Fire Marshal, Fire Hazard Severity Zones in the Local Responsibility Area (map dated 2025-03-24) (retrieved Oct 26, 2026) · FEMA, National Flood Hazard Layer — flood hazard zones (retrieved Oct 26, 2026) · FEMA, National Flood Hazard Layer — FIRM panels (retrieved Oct 26, 2026) · California Geological Survey, Alquist-Priolo Earthquake Fault Zones (retrieved Oct 26, 2026) · Zoning classes: our classification of RH-1 as single-family residential, checked against the zone description on Oct 24, 2026

Property & area intelligence timeline

79 events · 26 slow/stalled projects

Chronological history of building permit applications and issuances, snapshot-dated status changes, State housing entitlements, surrounding development within ½ mile, and area home-value trends.

Slow-moving or stalled projects (26)

Active projects spending 12+ months pre-issuance, 24+ months under construction, or 6+ months without new records

StalledAccessory dwelling unit at 300a University StIssued
0.47 mi SW
Permit issued and active for 8.5 yr (first record Apr 23, 2018), with no completion or new permit record in 5 yr. · 1 unit · $50,000 declared valuation
StalledAccessory dwelling unit at 302a University StIssued
0.47 mi SW
Permit issued and active for 8.5 yr (first record Apr 23, 2018), with no completion or new permit record in 5 yr. · 1 unit · $50,000 declared valuation
StalledAccessory dwelling unit at 306a University StIssued
0.47 mi SW
Permit issued and active for 8.5 yr (first record Apr 23, 2018), with no completion or new permit record in 5 yr. · 1 unit · $50,000 declared valuation
StalledAccessory dwelling unit at 308a University StIssued
0.48 mi SW
Permit issued and active for 8.5 yr (first record Apr 23, 2018), with no completion or new permit record in 5 yr. · 1 unit · $50,000 declared valuation
StalledAccessory dwelling unit at 626a Banks StIssued
0.26 mi NW
Permit issued and active for 6.4 yr (first record Jun 5, 2020), with no completion or new permit record in 4.9 yr. · 1 unit · $75,000 declared valuation
StalledAccessory dwelling unit at 239 Waterville StApplied
0.46 mi E
In "Applied" for 4.8 yr (since Jan 5, 2022), with no new permit record in 4.8 yr. · 1 unit · $80,000 declared valuation

202615 events

Oct 28, 2026 – Oct 29, 2026Snapshot windowNearby snapshot change
0.49 mi SE
Nearby remodel / interior alteration (405 Girard St): Status changed from suspend to cancelled
Record 202201246521 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 28, 2026 – Oct 29, 2026Snapshot windowNearby snapshot change
0.34 mi NW
Nearby windows / doors / siding (627 Anderson St): Status changed from suspend to cancelled
Record 202301130183 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 28, 2026 – Oct 29, 2026Snapshot windowNearby snapshot change
0.42 mi N
Nearby remodel / interior alteration (80 Bronte St): Status changed from plancheck to issued
Record 202603057023 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 28, 2026 – Oct 29, 2026Snapshot windowNearby snapshot change
0.42 mi N
Nearby remodel / interior alteration (80 Bronte St): Issued date changed from (blank) to 2026-10-28
Record 202603057023 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 28, 2026 – Oct 29, 2026Snapshot windowNearby snapshot change
0.48 mi NW
Nearby plan revision / deferred submittal (830 Cortland Av): First appeared in published agency feed
Record 202610280005 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 28, 2026 – Oct 29, 2026Snapshot windowNearby snapshot change
0.33 mi SE
Nearby roof replacement (231 Brussels St): First appeared in published agency feed
Record 202610280041 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 23, 2026 – Oct 24, 2026Snapshot windowNearby snapshot change
0.36 mi E
Nearby remodel / interior alteration (975 Bay Shore Bl): First appeared in published agency feed
Record 202602065491 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 23, 2026 – Oct 24, 2026Snapshot windowNearby snapshot change
0.28 mi N
Nearby remodel / interior alteration (238 Putnam St): Status changed from issued to complete
Record 202604139327 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 23, 2026 – Oct 24, 2026Snapshot windowNearby snapshot change
0.43 mi N
Nearby addition (adds square footage) (371 Banks St): Declared valuation changed from 250000 to 450000
Record 202605191496 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 23, 2026 – Oct 24, 2026Snapshot windowNearby snapshot change
0.43 mi N
Nearby addition (adds square footage) (371 Banks St): Description text was updated
Record 202605191496 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 23, 2026 – Oct 24, 2026Snapshot windowNearby snapshot change
0.28 mi N
Nearby plan revision / deferred submittal (448 Nevada St): Status changed from filed to issued
Record 202610099263 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 23, 2026 – Oct 24, 2026Snapshot windowNearby snapshot change
0.28 mi N
Nearby plan revision / deferred submittal (448 Nevada St): Issued date changed from (blank) to 2026-10-23
Record 202610099263 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 23, 2026 – Oct 24, 2026Snapshot windowNearby snapshot change
0.28 mi N
Nearby plan revision / deferred submittal (448 Nevada St): Description text was updated
Record 202610099263 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Oct 23, 2026 – Oct 24, 2026Snapshot windowNearby snapshot change
0.39 mi NW
Nearby remodel / interior alteration (655 Andover St): First appeared in published agency feed
Record 202610229782 · Detected between snapshots
Source: San Francisco Department of Building Inspection, Building Permits · Snapshot diff within ½ mile
Sep 18, 2026Nearby project · Applied
0.42 mi SW
Accessory dwelling unit at 1100 Silliman St — Applied
1100 Silliman St · 1 unit · $5,000 valuation
Source: San Francisco Department of Building Inspection, Building Permits & HCD APR (grouped project within ½ mile)

Showing 15 of 79 timeline events

Recorded sales & deed transfers: California county recorders do not publish open bulk deed-transfer feeds without owner-PII restrictions, so individual sale deeds are not redistributed here. For official assessment roll and recorded transfer history in San Francisco, inspect Property Information Map ↗.

Development graph & closer investigation

6 investigation leads

Cross-referenced intelligence from our historical development graph—connecting parcels, permits, entity-resolved builders, empirical review-time distributions, and neighborhood renovation trends.

Explore full San Francisco development graph →

Developments deserving closer investigation (6)

On this parcel & within ½ mile

Accessory dwelling unit at 256 Sweeny StIssuedNo new record in 12 mo
On this parcel
Active in "Issued" for 17 mo (first record Jun 6, 2025) with no new permit activity recorded in 12 mo.
New duplex at 816 Silliman StAppliedNo new record in 4.7 yr$1,250,000
0.28 mi SW
Active in "Applied" for 4.7 yr (first record Mar 1, 2022) with no new permit activity recorded in 4.7 yr. High-impact scale (2 housing units, $1,250,000 declared valuation across 1 permit).
Accessory dwelling unit at 338a Sweeny StIssuedNo new record in 4.7 yr
440 ft W
Active in "Issued" for 6 yr (first record Oct 15, 2020) with no new permit activity recorded in 4.7 yr.
2 new homes at 139a Sweeny StIssuedNo new record in 3.1 yr
0.13 mi E
Active in "Issued" for 9 yr (first record Nov 13, 2017) with no new permit activity recorded in 3.1 yr.
Accessory dwelling unit at 39 Girard StAppliedNo new record in 19 mo
0.25 mi E
Active in "Applied" for 19 mo (first record Apr 7, 2025) with no new permit activity recorded in 19 mo.
Accessory dwelling unit at 626a Banks StIssuedNo new record in 4.9 yr
0.26 mi NW
Active in "Issued" for 6.4 yr (first record Jun 5, 2020) with no new permit activity recorded in 4.9 yr.

Neighborhood renovation & housing momentum: Portola

Substantial improvements (additions, interior remodels, ADUs, commercial TI, and new builds) across 3,887 parcels

Rank #4 of 37 neighborhoods in acceleration

Last 12m vs prior 12m: 80 vs 55 permits
24m rate per 1,000 parcels: 34.7
5-year substantial permits: 340
Housing additions (24m): 20 units

Ownership & rental scenario calculator

Prop 13 tax estimate & area benchmarks

Area rent & home-value benchmarks (kept separate from your assumptions)

Click any benchmark to pre-fill the calculator

HUD Metro Fair Market Rent · San Francisco, CA HUD Metro FMR Area

HUD FY 2026 · 40th-percentile gross rent

Census ACS 5-year median gross rent (all bedroom counts combined):

Portola$2,094±$410

Area home-value benchmarks (not an appraisal)

ZIP & neighborhood medians

ACS Median Home Value · PortolaCensus ACS 2020–2024 owner-occupied self-reported median

$1,212,000±$35,800

1. Purchase, financing & Prop 13 tax reassessment

Purchase price ($)Down payment (%)$292,000Interest rate (%)Loan termClosing costs (%)$29,200

Prop 13 post-purchase property tax estimate

$1,473/mo ($17,678/yr · 1.21%)

Under California Proposition 13, the seller's historical assessed value does not carry over to a buyer. On sale, the parcel is reassessed at the purchase price: 1.00% base rate ($14,600/yr) + local voter-approved bond debt ($2,628/yr) + fixed direct levies/Mello-Roos ($450/yr).

Voter bond rate (%)$2,628/yrDirect levies / Mello-Roos ($/yr)Check Property Information Map ↗

2. Your rent & operating assumptions

Monthly gross rent ($)Your assumptionVacancy allowance (%)−$180/moManagement (%)$274/moMaintenance (%)$180/moCapEx reserve (%)$180/moInsurance ($/mo)$1,980/yrHOA dues ($/mo)Owner utilities ($/mo)

Insurance & hazard context:

This lot is outside mapped CAL FIRE Fire Hazard Severity Zones and FEMA Special Flood Hazard Areas. California insurance costs still vary widely by roof age, electrical panel, and carrier underwriting; obtain a property-specific quote rather than relying on rules of thumb.

3. Scenario results (based on your assumptions)

Net monthly cash flow: −$6,234
Cash-on-cash return: -23.3%
Cap rate (Year 1 NOI): 0.94%
DSCR (NOI / debt): 0.16x
Break-even gross rent: $11,655/mo
Break-even vacancy: 0% (negative at full occ.)

Monthly cash-flow breakdown (Effective gross $3,420 − Operating $2,272 − Debt $7,383)

Gross scheduled rent$3,600

Vacancy allowance (5%)−$180

Effective gross income$3,420

Prop 13 property tax (1.21%)−$1,473

Property insurance−$165

Management (8%), maintenance (5%) & CapEx (5%)−$634

Net Operating Income (NOI)+$1,148

Mortgage principal & interest (1,168,000 loan)−$7,383

Net monthly cash flow−$6,234

4. Sensitivity & rent-stabilization ceiling (San Francisco)

Scenario	Assumptions	Year 1 Rent	Year 1 Cash Flow	Cash-on-Cash	Break-Even Rent	Year 5 Cash Flow
Conservative	−8% starting rent, +3% vacancy, +3% combined maintenance/CapEx, 1.5%/yr rent growth	$3,312/mo	−$6,648/mo	-24.8%	$12,592/mo	−$6,638/mo
Base (your inputs)	Your entered assumptions, 3.0%/yr rent growth	$3,600/mo	−$6,234/mo	-23.3%	$11,655/mo	−$6,020/mo
Optimistic (cap-limited)	+6% starting rent, 3% vacancy, 4.2%/yr rent growth (capped by local ordinance ceiling of 4.2%/yr)	$3,816/mo	−$5,997/mo	-22.4%	$11,384/mo	−$5,591/mo

Rental regulatory context (informational only — not legal advice):

California AB 1482 (Tenant Protection Act, Civ. Code § 1947.12) caps annual rent increases at 5% + local CPI (max 10%) on covered properties. In San Francisco: San Francisco Rent Ordinance (Admin. Code Ch. 37) — annual allowable increase is 60% of Bay Area CPI (capped at 7%) for covered pre-June 1979 buildings. Official program rules ↗

Common statutory exemption signals under AB 1482

Housing issued a certificate of occupancy within the last 15 years (rolling exemption under AB 1482).
Separately alienable single-family homes or condominiums not owned by a corporation, REIT, or LLC with a corporate member (when required statutory notice is in the lease).
Owner-occupied duplexes where the owner occupied one unit from the start of the tenancy.

Development projects on this parcel

Accessory dwelling unit at 256 Sweeny St
Issued1 unitsJun 6, 2025 – Nov 5, 2025

We group related permits and State housing reports into projects. That grouping is our inference, not an official record.

Permit history on this parcel

2 records

Plan revision / deferred submittal202607295739
revision to permit 202506118403. change 2nd floor walk-in closet to full bath. non-structural interior work only.
revision to permit 202506118403. change 2nd floor walk-in closet to full bath. non-structural interior work only.
Applied
Jul 29, 2026
Issued
Aug 24, 2026
Recorded status
issued as of Aug 24, 2026
Declared valuation
$22,000
Accessory dwelling unit (new or conversion)202506118403
(n) 2-story horizontal addition at rear yard: add a 2 bedrooms, 2 bathrooms state program adu with family room, kitchen and deck. on the 2nd level remodel 2 bedrooms and 1 bathroom,add garage, staircase and deck. no exterior work visible from street.
(n) 2-story horizontal addition at rear yard: add a 2 bedrooms, 2 bathrooms state program adu with family room, kitchen and deck. on the 2nd level remodel 2 bedrooms and 1 bathroom,add garage, staircase and deck. no exterior work visible from street.
Applied
Jul 12, 2025
Issued
Nov 5, 2025
Recorded status
issued as of Nov 5, 2025
Declared valuation
$261,142

Source: San Francisco Department of Building Inspection, Building Permits · Geography: parcel (APN) · Retrieved Oct 29, 2026 · Filed, issued, and status dates come from the Department of Building Inspection, which dates each status change.

Housing activity reported to the State

Report year	Project / record	Type	Entitled	Permitted	Completed	Deed-restricted
2025	256 SWEENY STREET(2024-010263PRJ)	ADU · Renter	1 (Jun 6, 2025)	—	—	—
2025	—(202506118403)	ADU · Renter	—	1 (Nov 5, 2025)	—	—

Source: California HCD, Housing Element Annual Progress Report — Table A2 · Geography: project (parcel) · Retrieved Oct 26, 2026 · From San Francisco's Housing Element Annual Progress Reports. A project can appear in several report years as it moves from entitlement to permit to completion.

Zoning & planning

Zoning: RH-1: RESIDENTIAL- HOUSE, ONE FAMILY code

Source: San Francisco Planning, Zoning Map – Zoning Districts · Geography: zoning district polygon at parcel point · Retrieved Oct 29, 2026

Parcel facts

Lot size: —
Parcel type: Lot
Addresses on parcel: 2

Source: San Francisco Planning / DataSF, Parcels – Active and Retired · Geography: parcel · Retrieved Oct 29, 2026

Official records

Property Information Map
Zoning, permits, planning cases, and assessor data for this lot (SF Planning)
Assessor-Recorder
Look up block/lot 5859/012. Assessed value is not market value.
Property tax payment
Search by block/lot 5859/012 (SF Treasurer & Tax Collector)
DBI permit tracking
Search building permits, complaints, and inspections by address or block/lot
FEMA Flood Map Service Center
The official flood hazard map for this location. Our reading of it is under What could be built here.

This site does not show owner names.

Scenario

Assumptions

Year 1 Rent

Year 1 Cash Flow

Cash-on-Cash

Break-Even Rent

Year 5 Cash Flow

Conservative

−8% starting rent, +3% vacancy, +3% combined maintenance/CapEx, 1.5%/yr rent growth

$3,312/mo

−$6,648/mo

-24.8%

$12,592/mo

−$6,638/mo

Base (your inputs)

Your entered assumptions, 3.0%/yr rent growth

$3,600/mo

−$6,234/mo

-23.3%

$11,655/mo

−$6,020/mo

Optimistic (cap-limited)

+6% starting rent, 3% vacancy, 4.2%/yr rent growth (capped by local ordinance ceiling of 4.2%/yr)

$3,816/mo

−$5,997/mo

-22.4%

$11,384/mo

−$5,591/mo

Report year

Project / record

Type

Entitled

Permitted

Completed

Deed-restricted

2025

256 SWEENY STREET(2024-010263PRJ)

ADU · Renter

1 (Jun 6, 2025)

—

2025

—(202506118403)

ADU · Renter

—

1 (Nov 5, 2025)

—