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3900-3922 21St St

Eureka Valley/Dolores Heights, SF 94114 2752020 3 units · 1910

This building has more problems than most buildings in this neighborhood. Few open issues; problems get fixed quickly. A reasonable bet for a smooth tenancy.

NOVs (7y) vs. neighborhood
Compared to a typical building in Eureka Valley/Dolores Heights
At or below average
avg 1.3
1
FewerMore

This building has 1 novs (7y), at or below the Eureka Valley/Dolores Heights average of 1.3.

Rent & eviction protection

Is 3900-3922 21St St 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 1910
2 or more units
3 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
Units3
Floors
Year built1910
Total area4,199 sq ft
Property typeMulti-Family Residential
Tax statusNone
Blocklot2752020
Ownership

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

Owner name
Byrne Dominic
Mailing address
3900 21st St San Francisco CA 94114
Last sale
021820

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.

3900 21st St, San Francisco, CA 94114
3922 21st St, San Francisco, CA 94114
Augrented Insights
Initial analysis

The three-unit multi-family residential building at 3900-3922 21st Street in the Eureka Valley/Dolores Heights neighborhood, owned by Dominic Byrne, has undergone significant renovations and experienced several concerning incidents in recent years. Built in 1910, the property has seen substantial improvements since 2018, including window replacements, electrical upgrades, and various remodeling projects. The most notable recent work occurred in 2022-2023, with the removal of a load-bearing wall, extensive kitchen and bathroom renovations, and electrical system upgrades including a 200-amp service installation. However, these improvements were accompanied by serious violations, including an active building violation from June 2022 regarding unauthorized extensive demo and foundation work, and multiple complaints about construction without proper permits. A tenant buyout of $27,000 for three tenants at 3924 21st Street occurred in July 2022, coinciding with the period of unpermitted renovation work.

The building's permit history reveals a pattern of substantial investment in improvements, including recent work on the front entrance, side yard landscaping, and window replacements in 2023 and 2022 respectively. Historical permits show earlier upgrades including bathroom remodeling in 2007, window replacements in 1999, and reroofing work in 1990-1992. The property has faced various compliance issues over the years, including unauthorized construction work (2009), bathroom and kitchen modifications without permits (2009), and paint removal violations (2009). Recent 311 calls between 2024 and 2023 primarily relate to parking issues, graffiti, and debris management on or near the property. A single fire incident was recorded with no civilian injuries, categorized as an unintentional alarm transmission. While the building has received substantial improvements through various permits, the active building violations and history of unpermitted work raise concerns about compliance with building codes and regulations.

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

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Risk rating

How 3900-3922 21St St'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
28th percentile

Out of 1278 buildings in this neighborhood, 920 are predicted to be safer.

RiskiestSafest
Predicted 12-month outcome
61%
No DBI
violation
39%
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 complaints, owner's portfolio

Complaints across all of this owner's buildings over 7 years.

Neighborhood location

Precise location is a proxy for neighborhood-level risk — some SF blocks have systematically higher DBI activity.

12-Month severity forecast
No violation 51.2%
Moderate concern 29.7%
Severe concern 19.1%
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

3900-3922 21St St event timeline

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

2026
Building Permit Jun 18
Re-roofing: remove and replace roofing material / existing roofing material (in-kind)
$27,165 · Issued
311 RequestJun 13
Garbage and debris

See all 24 events

Full history back to 2021 — violations, complaints, permits, buyouts, and fire incidents.

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Every record we have

Full data for 3900-3922 21St St 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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