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3421-3431 20Th St

Inner Mission, SF 94110 3610049 6 units · 3 fl · 1906

This building has far more open problems than almost any other in the neighborhood. Renters here report frequent, slow-to-fix problems. Get repair promises in writing and check the unit before signing.

NOVs (7y) vs. neighborhood
Compared to a typical building in Inner Mission
Above average
avg 2.6
83
FewerMore

This building has 83 novs (7y), above the Inner Mission average of 2.6.

Rent & eviction protection

Is 3421-3431 20Th 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 1906
2 or more units
6 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
Units6
Floors3
Year built1906
Total area6,390 sq ft
Property typeMulti-Family Residential
Tax statusNone
Blocklot3610049
Ownership

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

Owner name
Biana Chernoguz 1997 Revoc
Mailing address
C/o Vladislav Chernoguz 2639 Turk Blvd San Francisco CA 94118
Last sale
101615

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.

3431 20th St, San Francisco, CA 94110
3423 20th St, San Francisco, CA 94110
3427 20th St, San Francisco, CA 94110
3421 20th St, San Francisco, CA 94110
3425 20th St, San Francisco, CA 94110
3429 20th St, San Francisco, CA 94110
Augrented Insights
Initial analysis

The 6-unit apartment building at 3421-3431 20th Street in the Inner Mission, owned by Biana Chernoguz 1997 Revoc trust, has undergone numerous significant renovations and faced several challenges since its construction in 1906. Most notably, the building is currently non-compliant with soft-story retrofit requirements (Tier 3), and there have been recurring issues with basic services such as heat and hot water, with multiple complaints in 2023 and 2024 regarding these systems. Recent improvements include a planned $24,000 complete replacement of furnaces and water heaters across all units (2024), and important safety upgrades such as a fire alarm system retrofit completed in late 2023 that replaced bells with horn strobes and added low-frequency horns in all units.

The building has experienced several significant maintenance and safety issues in recent years, including a substantial complaint in 2023 regarding multiple problems such as lack of lighting in common areas, damaged walls and floors, and missing smoke/CO detectors. Historical violations from 2016-2017 were addressed, which included mold remediation, window repairs, and various interior maintenance issues. The property has undergone extensive remodeling work, including kitchen and bathroom renovations in 2022 and siding replacement in 2023. Fire safety has been a recurring focus, with several violations related to alarm systems, sprinklers, and extinguishers noted between 2007 and 2020, though these appear to have been resolved. A recent pattern of complaints in 2024 suggests ongoing maintenance and habitability issues, including reports of rodents and ventilation problems, while multiple parking enforcement calls indicate persistent issues with parking management around the property.

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

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Risk rating

How 3421-3431 20Th 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
2th percentile

Out of 2380 buildings in this neighborhood, 2332 are predicted to be safer.

RiskiestSafest
Predicted 12-month outcome
13%
No DBI
violation
87%
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.

Notices of Violation (past 7 years)

DBI issued Notices of Violation at this address over the last 7 years — a direct record of code enforcement activity.

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 9.2%
Moderate concern 67.5%
Severe concern 23.3%
Estimated probability of receiving a DBI Notice of Violation in the next 12 months at each severity level. Model: full_hgb_balanced.
Apartment reviews

3421-3431 20Th St apartment reviews

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The story over time

3421-3431 20Th St event timeline

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

2026
Electrical Permit Jun 04
General wiring with no service upgrade lower unit adu
Issued
Plumbing PermitMar 24
Work category: 4pb; renew existing plumbing permit# pp20220606270 install new fire sprinkler system per nfpa 13 for the ground floor only. included 2" underground fire service. total 26 heads

See all 31 events

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

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Every record we have

Full data for 3421-3431 20Th 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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