CASTLETON-ON-HUDSON, N.Y. — Cleanup efforts were underway in parts of upstate New York on Thursday following two days of heavy rains that led to flash flooding, water rescues and the destruction of a centuries-old grist mill. First responders in Albany and several other towns said they rescued people from their homes and vehicles on Wednesday as waterways and streets flooded. Photos and videos posted online showed stranded cars with water up to their door windows, local farmland inundated by the heavy rains and fast-moving floodwaters spilling over roads. The water plant in Castleton-on-Hudson sustained damage during the flooding, leading to an advisory for local residents to boil their water and reduce water usage, officials said. Heavy rains earlier this week swamped other areas of New York as well as New Jersey and Pennsylvania, flooding streets and leading to water rescues.