City Limits looked at complaints received between Oct. 1 and Nov. 21 broken down by community district and found the pattern is similar to previous “heat seasons,” with the greatest number of 311 calls found in neighborhoods in upper Manhattan and several districts in The Bronx.

It’s “heat season” in New York City—the time period, from October through the end of May, when building owners are legally mandated to provide heat and hot water to tenants, or face potential penalties.

Since Oct. 1, New Yorkers have logged more than 40,000 heat and hot water complaints to 311 to the city’s Department of Housing, Preservation and Development (HPD), up about 17 percent compared to this time last year.

More than 16,000 of those complaints are still open, the data shows. More than 32,000 were were labeled as an issue affecting the entire building, as opposed to only an individual apartment, while 12,931 were listed as a “duplicate of a condition already reported by another tenant.” The greatest number of complaints in a single day so far came on Oct. 3, when temperatures dipped to a low of 47 degrees, weather records show.

City Limits looked at complaints received between Oct. 1 and Nov. 21 broken down by community district and found the pattern is similar to previous “heat seasons,” with the greatest number of 311 calls found in neighborhoods in upper Manhattan and several districts in The Bronx.

Manhattan Community Board 12, which spans Washington Heights and Inwood, had the greatest number of complaints, at 2,416, followed by Bronx Community Board 4 (Mt. Eden, Highbridge, and Concourse Village), Bronx CB7 (Bedford Park, Fordham, Kingsbridge, Norwood) and Bronx CB9 (Soundview, Parkchester, Castle Hill).

City law requires residential landlords to maintain indoor temperatures of at least 68 degrees when it's colder than 55 degrees during the day, and at least 62 degrees, regardless of outdoor temperature, at night. Building owners can face penalties of up to $500 a day for violating the rules, but it can be hard for tenants with persistent heat issues to get those problems resolved.

HPD only issues violations in a small percentage of cases, advocates complain. From Oct. 1 to Nov. 21, HPD issued violations in 1,681 of the 311 complaints received; another 9,075 complaints were closed after "conditions were corrected," the data shows.

A current City Council bill proposes doubling reinspection fees for landlords who receive multiple violations in the same year. Bronx Councilmember Pierina Sanchez, who introduced the legislation, said it was inspired by last year's fatal fire at the Twin Parks North West high rise, which was started by a faulty space heater.

“Thinking about what happened at Twin Parks, and how many tenants don’t have heat or hot water and call and call and call again and the issue doesn’t get resolved, $200 for a repeat inspection felt like a slap on the wrist,” she told City Limits earlier this year.