Free SF apartment background check

125 Mason St

Union Square, SF 94102 0331018

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
13
FewerMore

This building has 13 novs (7y), above the Union Square average of 6.9.

Rent & eviction protection

Is 125 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 unknown
2 or more units
? units
Property type
Multi-Family Residential
Zoning
C3G
Not rent-controlled. Buildings constructed after 1978 are generally exempt from SF rent increase limits under the Costa-Hawkins Act.

Based on SF Assessor records. Not legal advice — confirm with the SF Rent Board.

Building characteristics
Units
Floors
Year built
Total area
Property typeMulti-Family Residential
Tax statusWelfare
Blocklot0331018
Ownership

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

Owner name
Mason Street Affordable Hou
Mailing address
John Stewart Co, Inc 333 Taylor St San Francisco CA 94102
Last sale
060310

Landlord portfolio

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

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Augrented Insights
Initial analysis

125 Mason Street is a multi-family residential building in Union Square, classified as an apartment with 15 or more units, though the exact number of units is currently listed as 0. The building has experienced several significant maintenance and safety issues in recent months, including multiple fire safety violations and equipment concerns. Most notably, there have been recurring problems with the elevator (reported to malfunction every four months), ADA accessibility issues at the entrance, and various maintenance problems including electrical outages and plumbing issues in individual units. Between 2023 and 2024, multiple complaints were filed regarding building systems and safety equipment, including non-functional emergency systems, missing smoke detectors, and an expired elevator permit. The building underwent substantial water damage repairs in 2021 costing approximately $1.4 million, and there have been several fire safety compliance issues requiring attention, including recent violations related to sleeping area requirements, fire alarm systems, and maintenance documentation.

The property's maintenance history shows regular updates to essential systems, including boiler replacements and fire safety improvements. A series of building permits and plumbing work demonstrates ongoing attention to infrastructure maintenance, though some recent complaints suggest that certain systems may require further attention. The building's fire safety record shows a pattern of alarm system activations and some documented violations requiring correction, though many of these issues appear to have been addressed based on "abated" status in violation records. Recent 311 calls around the property have primarily related to street-level issues rather than building-specific problems, though some concerns about the surrounding area are noted. The most recent building complaint from August 2024 highlights continuing concerns about structural issues, though this complaint is currently marked as "Active."

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

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Risk rating

How 125 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
47th percentile

Out of 38 buildings in this neighborhood, 20 are predicted to be safer.

RiskiestSafest
Predicted 12-month outcome
10%
No DBI
violation
90%
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 complaint rate, owner's portfolio

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

DBI complaints, owner's portfolio

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

12-Month severity forecast
No violation 6.7%
Moderate concern 82.4%
Severe concern 10.9%
Estimated probability of receiving a DBI Notice of Violation in the next 12 months at each severity level. Model: full_hgb_balanced.
Apartment reviews

125 Mason St apartment reviews

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On the map

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The story over time

125 Mason St event timeline

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

2026
DBI Complaint May 13
Date last observed: 12-may-26; time last observed: 5/11/2026; floor: 2; exact location: main bldg; building type: residence/dwelling water intrusion; ; additional information: test;
Housing Inspection Services
DBI ComplaintMay 13
Date last observed: 08-may-26; floor: all; unit: all ; exact location: main bldg; building type: residence/dwelling fire safety/fire escape; ; additional information: the fire alarm goes off sporadically when triggered. for example, it may go off on the 4th floor, but not sound on the 10th floor. ;

See all 28 events

Full history back to 2019 — violations, complaints, permits, buyouts, and fire incidents.

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Every record we have

Full data for 125 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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