The head of good-government group Citizens Union turned himself in to police Tuesday morning on drug possession charges, The Post has learned.

Executive Director Dick Dadey, 59, surrendered at the 84th Precinct, where he is expected to receive a desk appearance ticket on misdemeanor charges of criminal possession of a controlled substance, sources said.

The charges stem from a search warrant executed by police in mid-September which turned up crystal meth and ecstasy at Dadey’s Brooklyn Heights home, sources said.

A source said the amount was for personal use – and not a “tremendous amount.”

Citizens Union announced Sept. 20 that Dadey was going on a leave of absence for “personal reasons” but did not elaborate.

Dadey made $189,000 working for the non-profit in 2015, according to the group’s tax records.