6401 S Kostner Ave
Nothing on record for this building in the last seven years. Our model still sees a moderate chance of maintenance problems in the next 12 months, from the owner's wider portfolio and the surrounding area rather than from anything recorded here. No public enforcement record to go on. Walk the building, ask the current tenants how repairs get handled, and get any promises in writing.
This building has 0 building violations (7y), at or below the West Lawn average of 1.0.
The bar and the rating point different ways because they measure different things: the bar counts building violations already on file, the rating forecasts the next 12 months.
What's in the 6401 S Kostner Ave report
| Units | 3 |
|---|---|
| Year built | 1949 |
| Stories | — |
| Building area | 2,814 sq ft |
| Property class | 211 |
| PIN (Cook County parcel) | 19222080010000 |
Registered owner per Cook County Assessor records.
Landlord portfolio
Other Chicago properties this owner holds, with a risk rating for each.
Unlock complete reportThe three-unit residential building at 6401 S Kostner Ave in West Lawn, owned by Andres C Sosa, has been standing since 1949 and has recently shown concerning patterns in its maintenance and safety record. Over the past seven years, there have been 13 documented service requests through the city's 311 system, with the majority of the most recent issues occurring in the summer of 2025 when multiple problems were reported, including water in the basement, sewer concerns, and a rodent infestation. Two building violations were also recorded in early 2026, though detailed information about these violations is not available in the summary. While the property has had one building permit issued in the past seven years, the relatively high number of service requests - particularly those related to moisture issues, sanitary systems, and pest control - suggests ongoing maintenance challenges. The most recent incident, an abandoned vehicle complaint, was recorded in May 2026 and marked as closed, though this appears unrelated to the building's residential conditions.
AI-generated · may contain errors · check the source data tables below
How 6401 S Kostner Ave's risk score is calculated
We trained a model on 7 years of Chicago code enforcement data — building violations, 311 complaint history, environmental enforcement, and owner track records. It estimates the probability that the City of Chicago will find a code violation at this address in the next 12 months. Lower % = safer.
What the score means for you
Lower risk — safer than most nearby
City inspectors rarely find violations here. Strong maintenance history and a clean complaint record.
Typical — about average for the neighborhood
Some past violations or complaints on record. Worth asking the landlord about any open issues before signing.
Higher risk — riskier than most nearby
Elevated violation and complaint history. City inspectors have found issues here before and are statistically likely to again.
Out of 699 buildings in this neighborhood, 622 are predicted to be safer. The band is relative to this neighborhood, so a share of every neighborhood falls in each colour.
violation
likely
What's driving this score
The data points that most influenced this building's risk rating — ranked by the weight the model placed on each one.
6401 S Kostner Ave apartment reviews
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6401 S Kostner Ave event timeline
Building violations, environmental complaints and enforcement, permits, scofflaw listings, and 311 calls — most recent records in order.
See all 5 events
Full history back to 2025 — violations, complaints, permits, and 311 calls.
Unlock complete timelineFull data for 6401 S Kostner Ave apartments
Chicago public datasets for this parcel — building violations, permits, 311 calls, environmental complaints and enforcement, scofflaw listings, and vacant building registrations.
What this is
Violations issued by the City of Chicago Department of Buildings against this parcel.
| Violation # | Date | Category | Status | Address |
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What this is
Violations issued for failure to register or maintain a vacant or abandoned building.
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What this is
Building permits issued by the City of Chicago for new construction, alterations, and repairs at this parcel.
| Permit # | Issued | Status | Description |
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What this is
Chicago 311 service requests recorded at this parcel — maintenance complaints and quality-of-life requests.
| SR # | Created | Type | Department | Status |
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What this is
Environmental complaints filed about this property with the City of Chicago.
| Complaint # | Date | Type | Inspector | Resolution | Resolved |
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What this is
Formal environmental enforcement cases brought against this property.
| Case # | Date | Type | Violation | Disposition | Status | Fine |
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Cancel anytime · Data sourced from the City of Chicago Department of Buildings, Chicago 311, Cook County Assessor & the Chicago Data Portal