In the modest township of Little Falls, NJ, on the Passaic River, evacuations started Sunday and the river's flooding crest is now expected sometime Tuesday.
"We have about 20 people in our shelter," said Office of Emergency Management Director Fred Patella Monday morning.
A U.S. Geological Survey gauge on the river in Little Falls shows the Passaic was already 3.75 feet above flood stage Monday morning, with more to come.
The town's website started warning people Sunday night to get to higher ground.
In Pequannock, Route 23, a major artery to northwest New Jersey, was shut down from rising waters.
And in Jefferson Township, reports of a dam breaking on Lake Shawnee were not quite correct according to Mayor Russ Felter.
He told NBCNewYork there was a "breech alongside the dam" that was causing water to rush downstream to popular Lake Hopatcong. But engineers were already on the scene to address that, and the Mayor said the amount of water getting through should not be enough to cause actual flooding on Hopatcong, even water levels are up.
"I helped one homeowner move his stuff," Mayor Felter said about a flooding problem elsewhere in Jefferson Township on Sunday.
"About four or five homes were flooded" in Lower Berkshire Valley near Rt. 15, according to the mayor.
Saturday and Sunday were bad days for Bound Brook and Manville on the Raritan River in Central Jersey. There were mandatory evacuations in Bound Brook, which was devastated by Hurricane Floyd in 1999, and a Nor'easter in 2007.
Upriver in Manville, there were voluntary evacuations in Lost Valley, a large residential area that was hammered by Floyd in 1999.
As of Monday morning, the USGS was reporting 15 locations across New Jersey where rivers were above flood stage.