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451-453 20Th Ave

Central Richmond, SF 94121 1524008B 2 units · 2 fl · 1914

This building has significantly more problems than most nearby buildings. 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
Above average
avg 0.5
2
FewerMore

This building has 2 novs (7y), above the Central Richmond average of 0.5.

Rent & eviction protection

Is 451-453 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 1914
2 or more units
2 units
Property type
Multi-Family Residential
Zoning
RM1
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
Units2
Floors2
Year built1914
Total area2,378 sq ft
Property typeMulti-Family Residential
Tax statusHome Owners
Blocklot1524008B
Ownership

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

Owner name
Ze Sheng Liao & Li Yun Pu L
Mailing address
Liao Ze Sheng & Li Yun Pu T 2930 Lawton St San Francisco CA 94122
Last sale
102209

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.

451 20th Ave, San Francisco, CA 94121
453 20th Ave, San Francisco, CA 94121
Augrented Insights
Initial analysis

The property at 451-453 20th Avenue is a two-unit, two-story multi-family residential building located in the Central Richmond neighborhood, constructed in 1914. The building has undergone several significant changes over the years, with the most pressing current issue being the active violation case from 2021 regarding unauthorized dwelling units in the ground floor, each equipped with a full kitchen, bathroom, and bedroom. This violation, initiated in May 2021, remains active as of the latest records. The property has a history of unauthorized modifications and permit violations, including a 2020 incident involving unpermitted siding replacement work (approximately 900 square feet) at the rear of the building. Several permitted improvements have been made over the years, including a major horizontal addition completed in 1998 and various interior remodels in 1987. Recent infrastructure maintenance includes the replacement of a sidewalk trap in 2011 and electrical system upgrades in 2007.

The building's recent history shows multiple tenant-related issues, including a tenant buyout recorded at 455 20th Avenue in January 2025. The property has experienced recurrent issues with parking violations and street-related concerns, as evidenced by numerous 311 calls between 2022 and 2024, primarily regarding blocked driveways and illegal parking. A damaged tree was reported and documented in September 2023. The current status of the pending unit legalization permit (under review) suggests ongoing efforts to address historical permit violations, though this process has been extended over multiple years. While the building has maintained basic structural integrity and completed several improvements, the recurring issues with unauthorized units and parking violations indicate ongoing challenges with property management and compliance with local regulations.

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

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Risk rating

How 451-453 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
17th percentile

Out of 2250 buildings in this neighborhood, 1868 are predicted to be safer.

RiskiestSafest
Predicted 12-month outcome
70%
No DBI
violation
30%
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.

DBI tenant complaints (past 7 years)

Formal complaints tenants filed with DBI about this building over 7 years.

DBI complaint rate, owner's portfolio

Per-building complaint rate across the owner's portfolio.

Director's hearing rate, owner's portfolio

Per-building rate of director's hearings across the owner's portfolio.

12-Month severity forecast
No violation 19.0%
Moderate concern 70.1%
Severe concern 10.9%
Estimated probability of receiving a DBI Notice of Violation in the next 12 months at each severity level. Model: full_hgb_balanced.
Apartment reviews

451-453 20Th Ave apartment reviews

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The story over time

451-453 20Th Ave event timeline

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

2025
Tenant Buyout Jan 06
Tenant buyout · $83,412
3 tenant(s)

See all 10 events

Full history back to 2020 — violations, complaints, permits, buyouts, and fire incidents.

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Every record we have

Full data for 451-453 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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