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172-174 21St Ave

Lake Street, SF 94121 1380024 2 units · 2 fl · 1921

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 Lake Street
At or below average
avg 0.6
0
FewerMore

This building has 0 novs (7y), at or below the Lake Street average of 0.6.

Rent & eviction protection

Is 172-174 21St 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 1921
2 or more units
2 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
Units2
Floors2
Year built1921
Total area3,450 sq ft
Property typeMulti-Family Residential
Tax statusHome Owners
Blocklot1380024
Ownership

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

Owner name
Chapin Ralph O & Myra B
Mailing address
174 21st Ave San Francisco CA 94121
Last sale
032814

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.

172 21st Ave, San Francisco, CA 94121
174 21st Ave, San Francisco, CA 94121
Augrented Insights
Initial analysis

This two-unit, two-story multi-family residential building located at 172-174 21st Avenue in the Lake-Presidio neighborhood was built in 1921 and is currently owned by Ralph O. and Myra B. Chapin. The property has a significant history of building permit activity, with the most pressing issue being an active building violation from December 2006 regarding an unauthorized rear deck construction that prompted numerous compliance efforts. This violation, filed under complaint number 200684924, remains active despite attempts to address it through permits and a subsequent variance request. The deck issue was eventually partially resolved with a completed permit in May 2018 that documented a $15,000 deck removal and replacement project.

The building has undergone several significant improvements over the years, including a kitchen remodel in 2007 valued at $15,000 which included electrical updates, cabinet replacements, and gas line installations, along with plumbing modifications for a laundry area. The property experienced recurring sewer issues between 2011 and 2015, with multiple sewage backup incidents requiring attention from PUC Sewer Operations, suggesting potential ongoing infrastructure challenges. More recently, there have been three garbage and debris-related 311 calls between October 2024 and January 2025, though these were street cleaning matters rather than building-specific issues. Two sidewalk defect complaints were filed in 2011 and October 2024, with the latter currently showing as an open case.

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

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Risk rating

How 172-174 21St 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
61th percentile

Out of 660 buildings in this neighborhood, 257 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.

Construction spend, owner's portfolio

Estimated permit value across all of this owner's buildings.

DBI complaint rate, owner's portfolio

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

Estimated permit spend (past 7 years)

Dollar value of permits pulled at this address — large recent spend can signal deferred-maintenance catch-up.

12-Month severity forecast
No violation 81.0%
Moderate concern 14.0%
Severe concern 4.9%
Estimated probability of receiving a DBI Notice of Violation in the next 12 months at each severity level. Model: full_hgb_balanced.
Apartment reviews

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The story over time

172-174 21St Ave event timeline

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

No dated public records on file yet.
Every record we have

Full data for 172-174 21St 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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