candidate: A short list of the types of special districts includes : Air pollution control districts Air quality management districts Airport districts Bridge or highway districts California water districts Community facilities districts ( Mello - Roos districts ) Community services districts County sanitation districts County service areas County water districts County waterworks districts Fire protection districts Harbor and port districts Healthcare / Health Care / Health districts Improvement districts Irrigation districts Joint power agencies Joint highway districts Library districts Metropolitan water districts Mosquito abatement districts Municipal utility districts Municipal water districts Permanent road divisions Pest control districts Police protection districts Public cemetery districts Public utility districts Reclamation districts Recreation and park districts Redevelopment agencies Resource conservation districts Sanitary districts Separation of grade districts Service zones of special districts Sewer districts Sewer maintenance districts Special assessment districts Transit or rapid transit districts Unified or union high school library districts Vector control districts