New sanitation department rules could mean big fines for nonprofit groups that clean up numerous New York City blocks, city councilmembers write in a new letter.

Every day, workers for business improvement districts and other nonprofits fan out across the city and collect refuse, leaving bagged trash near public trash cans for collection. Many of the workers are employed by the Association of Community Employment, also known as ACE, which provides jobs to homeless people. But 25 councilmembers write in the letter that new sanitation department rules now require those groups to find “alternative sites” to leave their trash or haul it directly to sanitation facilities.

“These are people who are walking the streets with their brooms,” said Councilmember Shaun Abreu, who chairs the sanitation committee and signed the letter.

Abreu said he and his colleagues support the city’s containerization plan, but added that groups providing supplemental cleaning services need more time to comply.

“These groups are not that well-funded so they would have had to purchase their own bins. … To just throw this on them with just days’ notice and with no phased implementation, that was hard for them to swallow,” he said.

The letter was sent to Sanitation Commissioner Jessica Tisch on Tuesday. On Wednesday, sanitation spokesperson Josh Goodman said enforcement would not take effect until next summer.

That will come as a relief to the nonprofits. They’d just learned of the new rules in July, which they had heard went into effect in November, according to Abreu.

“For them, they just had no idea what was really happening,” he said. “They were left in the dark. They didn’t know how this unannounced program, what impact it would have on them.”

“My understanding is they were threatened with fines if they wouldn’t comply by early November,” he said.

Businesses that leave trash on the curb can be fined $50, an amount that increases with subsequent offenses.

Business improvement districts are similar to merchant associations. Each business within a district contributes extra money to fund services such as additional trash pickup, which makes the area more appealing to shoppers.