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3440 20Th St

Inner Mission, SF 94110 3595048 39 units · 3 fl · 1965

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
10
FewerMore

This building has 10 novs (7y), above the Inner Mission average of 2.6.

Rent & eviction protection

Is 3440 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 1965
2 or more units
39 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.

Statewide backstop · AB 1482

California Tenant Protection Act of 2019

Even when a building isn't covered by local rent stabilization, the statewide Tenant Protection Act (AB 1482) may still apply. It caps annual rent increases and requires the landlord to state a legal reason to end most tenancies.

15+ years since occupancy
Built 1965
Annual rent increase cap
5% + CPI, max 10%
Just-cause eviction
After 12 months
Local rent control likely takes priority. This building appears to fall under the local ordinance above, which is stronger than AB 1482. Where a local just-cause ordinance applies, its rules govern instead of the state cap.

AB 1482 does not apply to single-family homes and condos unless owned by a corporation, REIT, or an LLC with a corporate member; to owner-occupied duplexes; or to deed-restricted affordable housing. The Act is in effect until January 1, 2030. Not legal advice — see the California landlord–tenant guide.

Building characteristics
Units39
Floors3
Year built1965
Total area26,754 sq ft
Property typeMulti-Family Residential
Tax statusNone
Blocklot3595048
Ownership

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

Owner name
Mailing address
Steven C. Thrower 1 Bush St Ste 900 San Francisco CA 94104
Last sale
110918

Landlord portfolio

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

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Augrented Insights
Initial analysis

The 39-unit, 3-story apartment building at 3440 20th Street in San Francisco's Inner Mission neighborhood has undergone several significant renovations and ongoing maintenance over the past few years. Most notably, a major project completed in 2020 added 9 accessory dwelling units (ADUs), converting existing garage spaces and increasing the total unit count to 48. This project included substantial fire safety upgrades with the installation of new fire devices throughout the building, and the implementation of a new fire sprinkler system on the ground floor. Recent maintenance activities include multiple washing machine and dryer installations in various units (2022-2023), boiler replacements (2021-2023), and electrical upgrades including a new 1200-amp service installation (2019).

The building has faced some concerning issues in recent years, including a ceiling leak and mold problem reported in early 2024, and complaints about non-handicap accessibility filed in late 2024. There were also multiple construction-related complaints during 2020-2021 regarding work being done without proper permits, including concerns about structural integrity and window coverings during construction. Fire safety has been a recurring concern, with violations and complaints about sleeping area requirements and blocked exits documented in 2023, 2021, and earlier years, though most have been corrected. The property has experienced several plumbing and heating system updates, including the installation of four new hot water boilers in 2023 and work to address previously unpermitted boiler installations. Recent maintenance issues have also been noted, including reports of rodent infestation and garbage management problems in late 2024.

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

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Risk rating

How 3440 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
0th percentile

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

RiskiestSafest
Predicted 12-month outcome
9%
No DBI
violation
91%
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.

NOV rate, owner's portfolio

Per-building NOV rate across everything this owner manages — high rates signal pattern neglect.

12-Month severity forecast
No violation 3.3%
Moderate concern 84.6%
Severe concern 12.1%
Estimated probability of receiving a DBI Notice of Violation in the next 12 months at each severity level. Model: full_hgb_balanced.
Apartment reviews

3440 20Th St apartment reviews

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On the map

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The story over time

3440 20Th St event timeline

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

2025
Building Permit Nov 10
Common area: structural wall repair. structural construction includes new studs, plywood and mudsill. nov# 202544910
$5,000 · Issued
Building Violation (NOV)Oct 15
An emergency response revealed a car into garage door & rear of garage damage # rear-bearing/shearwall - 3rd garage from 20th st along capp st north bound. pd 250579497 code/section: sfbc 102a monthly monitoring fee applies. code/section: sfbc 110a, table 1a-k

See all 29 events

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

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Every record we have

Full data for 3440 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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