Flood waters seriously damaged parts of Liverpool's Childwall Synagogue this week after torrential downpours left large parts of the city under water and many main roads closed.
The shul's Harris Polak and Aida Shifrin halls were filled with two inches of water as Tuesday's rains led to the collapse of a ceiling over one of the rooms.
Overflow from drains, which struggled to cope, brought more water into the Childwall building, which sits 20ft below street level.
The synagogue has been attempting to raise between £75,000 and £100,000 for essential work that is needed on its roof, heating and wiring.
Norman Goldstone, chairman of Childwall Hebrew Congregation, said a caretakers' team had spent five hours clearing water out of affected areas, and that the main shul, offices and bet hamedrash were undamaged.
He said: "It's not the end of the world. The inside ceilings have caved in but it's not going to close the shul. We've got a team coming next week to clear away the rubble that fell from the ceilings."
Stapely Jewish Care Home was unaffected, despite flooding in nearby streets. Staff at King David High School reported long delays to get home, but pupils were unaffected.
Merseyside police and the city council reported major routes such as Allerton Road and Queens Drive in Childwall, near to Liverpool's Jewish community, were cut off by flood waters.