Thomas Sullivan, director of the Montgomery County Department of Public Safety, said about 6,500 emergency calls - including 1,500 in one hour - were received Tuesday for everything from fires to water rescues. He said the normal emergency call volume is about 3,200.
"We thought we had dodged the bullet, but last night, we made up for it," Sullivan said.
Sullivan said areas east of the Perkiomen Creek, including Whitemarsh, Ambler, Whitpain and Cheltenham, were hardest hit by the rain. According to the National Weather Service, Ambler received 7.9 inches of rain Tuesday, King of Prussia 6.15 inches and Wynnewood 6.28 inches.
In comparison, Pottstown received 3.39 inches of rain, the weather service said.
The deluge of calls forced emergency units from western Montgomery County, especially those with water rescue equipment, to be sent to areas outside Philadelphia.
Ninety-three fire companies were involved in rescues or remained on standby in eastern Montgomery County, including the Humane Fire Company from Royersford, Goodwill Fire Company from Pottstown and the New Hanover and Limerick fire companies. Personnel even had to be called in from Berks, Bucks and Lehigh counties, Sullivan said.
"It's unheard of to dispatch from Lehigh County," Sullivan said.
Engine 10, a pumper truck from the Phillies Fire Company in Pottstown, left for Upper Dublin just before 8 p.m. Tuesday and was detoured three times en route to the township's municipal building, said driver Neil Fuerman.
Fuerman and several Phillies volunteers were dispatched to a water rescue while in Upper Dublin but were unable to assist due to their location to the vehicle in the water, Fuerman said. The unit remained on standby and arrived back in Pottstown just before 2 a.m. Wednesday.
Collegeville Fire Company Chief Jeff Wentworth said 12 members went to the Conshohocken area with their marine unit and heavy rescue truck for about seven hours Tuesday night, providing standby assistance and responding to some water rescues.
Wentworth said Keystone Fire Company from Boyertown also assisted with several water rescues in the Skippack area.
According to a press release from the county, flooding and accidents on the Schuylkill Expressway stranded about 70 people until emergency personnel could assist them.
"It's the second time in a month we had close the Expressway," Sullivan said.
Sullivan said crews were out Wednesday surveying the flood damage. Members of the Pennsylvania and Federal Emergency Management Associations also are scheduled to take a look at the damage, he said.
Similar surveys were conducted in Chester County, where areas like Downingtown, West Chester, Avondale and Kennett Square were hardest hit, according to Patty Mains, public information officer for Chester County Emergency Services.
The weather service said 6.66 inches of rain fell in Downingtown and 8.91 inches in West Chester.
Mains said more than 100 water rescues were completed Tuesday, and twice the number of usual calls - 1,800 - were received.
Mains said despite the influx of emergency calls, no additional personnel had to be dispatched from other parts of the county for assistance.