As New York City waits for the release of the public advocate’s new worst landlord watchlist, one building in East New York is already raising questions about whether anything has changed. The building at 509 Hinsdale St. is owned by Barry Singer, the landlord who ranked No. 1 on last year’s watchlist. While the list ranks landlords — not individual buildings — this property was cited by the public advocate as one example of the conditions that helped put Singer at the top. When last year’s list was released, city records showed more than 270 open housing violations at this one building, which has just 21 apartments. Those problems included mold, water leaks, mice and roaches, broken floors and ceilings, and apartments without working smoke or carbon monoxide detectors. Fast forward to today, and city housing records now show about 400 open violations at the same address. Recent listings on the city’s Housing Preservation and Development website show ongoing issues such as pest infestations, water damage, broken doors and locks, damaged ceilings and walls, and problems with basic safety equipment inside apartments. The city’s Public Advocate, Jumaane Williams, says he releases the worst landlord watchlist each year to call attention to landlords who repeatedly fail to fix problems — and to give tenants a tool to push for change. Williams has said that when conditions continue to pile up, buildings should be taken from neglectful landlords and transferred either to tenants first or to someone more responsible. Later today, Williams is expected to release the new watchlist, rally with tenants and advocates, and outline next steps for holding landlords accountable. The full list is expected to show whether familiar names remain — or if new landlords will take the top spots this year.