Free SF apartment background check

147-149 Mason St

Union Square, SF 94102 0331017 57 units · 8 fl · 2009

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 Union Square
Above average
avg 6.9
56
FewerMore

This building has 56 novs (7y), above the Union Square average of 6.9.

Rent & eviction protection

Is 147-149 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 2009
2 or more units
57 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
Units57
Floors8
Year built2009
Total area36,804 sq ft
Property typeMulti-Family Residential
Tax statusWelfare
Blocklot0331017
Ownership

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

Owner name
Mason Street Housing Assoc
Mailing address
John Stewart Co 333 Taylor St San Francisco CA 94102
Last sale
061419

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.

149 Mason St, San Francisco, CA 94102
147 Mason St, San Francisco, CA 94102
Augrented Insights
Initial analysis

The 57-unit, 8-story multi-family residential building at 147-149 Mason Street, owned by Mason Street Housing Association, has experienced several significant maintenance and safety issues in recent years. Most notably, from July 2022 to February 2023, there were multiple violations related to boiler permit compliance, with five separate notices of violation (NOV) issued for various boiler units (serial numbers K20061492, K20061495, and 18261108660555). The building has also faced recurring fire safety concerns, with violations in 2023-2024 related to alarm systems, sleeping area requirements, and blocked exits. Recent complaints filed in 2024 include two incidents regarding broken windows (July 2024), black water from taps (April 2024), and construction noise (March 2024). The building's accessibility features have also been a concern, with multiple complaints in late 2023 regarding broken ADA doors and intercom systems.

The property's maintenance history shows ongoing infrastructure work, including a hot water boiler replacement in 2019, though more recent issues suggest some maintenance challenges. Between 2011-2013, various improvements were made, including subway retail space build-outs and fire safety system upgrades. The building has undergone multiple plumbing and electrical system installations since its 2009 construction, including a complete sprinkler system, underground plumbing work, and extensive electrical system installations. Recent 311 calls from January 2025 indicate issues with garbage collection services outside the building, though these appear to be municipal service matters rather than building-specific issues. The clustering of recent complaints from late 2023 to early 2024 suggests some ongoing challenges with building maintenance and system reliability, particularly regarding safety systems and accessibility features.

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

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Risk rating

How 147-149 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
3th percentile

Out of 38 buildings in this neighborhood, 37 are predicted to be safer.

RiskiestSafest
Predicted 12-month outcome
6%
No DBI
violation
94%
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 3.9%
Moderate concern 60.6%
Severe concern 35.5%
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

147-149 Mason St event timeline

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

2026
311 & DBI Complaint Mar 19
Doors windows broken defective
Residential Building
311 & DBI ComplaintMar 16
Public health

See all 19 events

Full history back to 2023 — violations, complaints, permits, buyouts, and fire incidents.

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Every record we have

Full data for 147-149 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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