Free SF apartment background check

503-509 20Th Ave

Central Richmond, SF 94121 1563001 4 units · 2 fl · 1920

This building has a higher-than-average number of open problems nearby. Few open issues; problems get fixed quickly. A reasonable bet for a smooth tenancy.

NOVs (7y) vs. neighborhood
Compared to a typical building in Central Richmond
At or below average
avg 0.5
0
FewerMore

This building has 0 novs (7y), at or below the Central Richmond average of 0.5.

Rent & eviction protection

Is 503-509 20Th Ave rent-controlled?

San Francisco's Rent Ordinance caps rent increases and provides eviction protection for most residential units built before 1979 with 2+ units. Here's how this building scores.

Built before 1979
Built 1920
2 or more units
4 units
Property type
Multi-Family Residential
Zoning
RH2
Likely rent-controlled. Building age and unit count suggest this property falls under San Francisco's Rent Ordinance.

Based on SF Assessor records. Not legal advice — confirm with the SF Rent Board.

Building characteristics
Units4
Floors2
Year built1920
Total area4,030 sq ft
Property typeMulti-Family Residential
Tax statusNone
Blocklot1563001
Ownership

Registered owner per SF Assessor-Recorder (secured roll).

Owner name
Kit Han Wong 2003 Revocable
Mailing address
867 Clearfield Dr Millbrae CA 94030
Last sale
040999

Landlord portfolio

Other SF properties this owner holds, with risk grades for each.

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Multiple entrances & addresses

Included addresses

All street addresses sharing this blocklot that are covered by this report.

505 20th Ave, San Francisco, CA 94121
509 20th Ave, San Francisco, CA 94121
503 20th Ave, San Francisco, CA 94121
507 20th Ave, San Francisco, CA 94121
Augrented Insights
Initial analysis

The property at 503-509 20th Avenue in San Francisco's Central Richmond neighborhood is a 4-unit, 2-story, multi-family residential building constructed in 1920. The building has undergone several significant maintenance and upgrade projects over recent years, with the most recent being the installation of James Hardie siding in late 2023, costing $45,000, which was completed in November 2023 after initial approval in October. Historical maintenance records show various improvements including reroofing in 1997 and stair repairs in 2007. The building has experienced several issues requiring attention, most notably during a 2002 routine inspection that revealed multiple violations including problems with stairs, plumbing, electrical systems, fire safety concerns, and sanitation issues, all of which were abated by January 2003.

More recent inspections in 2010 and 2014 have shown ongoing concerns, with the 2014 inspection identifying issues with handrails, carbon monoxide and smoke alarm compliance, and structural maintenance documentation. The property has faced some maintenance challenges in recent months, with multiple 311 calls in 2024 reporting sewage backups, garbage and debris issues, and graffiti on the sidewalk. Two minor fire-related incidents were recorded, both with no civilian injuries. While the building has had its share of maintenance issues over the years, recent investments in exterior improvements suggest active management, though there remain some outstanding compliance matters from the 2014 inspection that appear to be still unresolved.

AI-generated · may contain errors · check the source data tables below

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Risk rating

How 503-509 20Th Ave's risk score is calculated

We trained a model on 7 years of SF DBI inspection data — notice of violation filings, complaint history, and owner track records. It estimates the probability that DBI inspectors will issue a Notice of Violation at this address in the next 12 months. Lower % = safer.

What the score means for you

Grade A–B — Low risk

DBI rarely finds violations here. Strong maintenance history and a clean complaint record.

Grade C — Moderate risk

Some past violations or complaints on record. Worth asking the landlord about any open issues before signing.

Grade D–F — High risk

Elevated violation and complaint history. DBI has found issues here before and is statistically likely to again.

Neighborhood percentile
62th percentile

Out of 2250 buildings in this neighborhood, 855 are predicted to be safer.

RiskiestSafest
Predicted 12-month outcome
85%
No DBI
violation
15%
DBI violation
likely
Model explanation

What's driving this score

The three data points that most influenced this building's risk rating — ranked by the weight the model placed on each one.

Number of units

The number of units affects how the model reads complaint and violation totals — more units means more potential sources.

Building size

Total floor area — a proxy for building scale and the number of systems (plumbing, electrical, HVAC) that can fail.

Building age

Older buildings tend to have more maintenance challenges; SF's pre-1906 earthquake housing stock carries distinct risk.

12-Month severity forecast
No violation 80.6%
Moderate concern 9.6%
Severe concern 9.8%
Estimated probability of receiving a DBI Notice of Violation in the next 12 months at each severity level. Model: full_hgb_balanced.
Apartment reviews

503-509 20Th Ave apartment reviews

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The story over time

503-509 20Th Ave event timeline

Violations, complaints, fire incidents, permits, and buyouts — most recent records in order.

2026
311 Request Apr 07
Garbage and debris
other loose garbage debris yard waste
311 RequestApr 04
Blocking driveway cite tow

See all 7 events

Full history back to 2023 — violations, complaints, permits, buyouts, and fire incidents.

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Every record we have

Full data for 503-509 20Th Ave apartments

13 SF public datasets for this parcel — permits, violations, complaints, fire records, 311 calls, planning records, and buyouts.

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Cancel anytime · Data sourced from SF Open Data, DBI, SFFD, SF Rent Board & Planning

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