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124 Mason St

Union Square, SF 94102 0330013 31 units · 8 fl · 1913

This building has a higher-than-average number of open problems nearby. 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 Union Square
Above average
avg 6.9
16
FewerMore

This building has 16 novs (7y), above the Union Square average of 6.9.

Rent & eviction protection

Is 124 Mason 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 1913
2 or more units
31 units
Property type
Multi-Family Residential
Zoning
C3G
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
Units31
Floors8
Year built1913
Total area12,440 sq ft
Property typeMulti-Family Residential
Tax statusNone
Blocklot0330013
Ownership

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

Owner name
124 Mason St Prpty Llc
Mailing address
Steven C. Thrower 1 Bush St Ste 900 San Francisco CA 94104
Last sale
102512

Landlord portfolio

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

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Augrented Insights
Initial analysis

The 8-story multi-family residential building at 124 Mason Street, constructed in 1913, is currently owned by 124 Mason St Prpty LLC and contains 31 units. The building has undergone significant recent activity, with multiple unit renovations between 2019-2025, including kitchen and bathroom upgrades, washer/dryer installations, and electrical system improvements. Notable renovations include work in units 804, 102, 401, 602, and 704, with the most recent fire alarm system upgrade scheduled for 2025 to comply with SFFC requirements. The property has experienced recurring elevator issues, with multiple complaints between 2005-2017, and has faced fire safety challenges in recent months, with multiple violations issued between March-October 2024 related to alarm systems, sleeping area requirements, and sprinkler systems. A concerning pattern of fire code violations has emerged in 2024, with citations issued in March, May, September, and October. The building has documented tenant buyouts in 2018 at 56 Mason Street, each totaling $193,750 for one tenant.

The property has undergone various infrastructure improvements, including a 1000-amp electrical service upgrade in 2016, and comprehensive fire alarm system upgrades in 2019 to meet safety standards. However, there have been persistent maintenance challenges, particularly with the elevator system and fire safety compliance. Recent 311 calls from January 2025 indicate ongoing concerns with garbage, encampments, and graffiti in the vicinity of the building. The building's history includes some significant incidents, such as lead paint contamination complaints in 2015 and multiple elevator entrapments requiring emergency response. While many previous violations have been addressed, the recent surge in fire code violations warrants attention, with multiple citations issued in 2024 for various fire safety concerns, including alarm systems, sprinkler systems, and sleeping area requirements.

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

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Risk rating

How 124 Mason 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
32th percentile

Out of 38 buildings in this neighborhood, 26 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.

Building size

Total floor area — a proxy for building scale and the number of systems (plumbing, electrical, HVAC) that can fail.

Number of units

The number of units affects how the model reads complaint and violation totals — more units means more potential sources.

Neighborhood (ZIP code)

The ZIP code captures local housing market and enforcement patterns that affect all buildings in the area.

12-Month severity forecast
No violation 9.2%
Moderate concern 83.7%
Severe concern 7.2%
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

124 Mason St event timeline

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

2026
Building Permit Jun 01
Install (e) non-electrical double sided street facing projecting sign for "adan cafe" called sign a
$2,400 · Issued
311 RequestMay 17
Public works

See all 37 events

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

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Every record we have

Full data for 124 Mason 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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