"There are many, many hazards in the streets. Many downed power lines. Still many flooded areas," Mayor Cory Booker told CNN. "People's safety is still principally important."
For example, standing water is potentially dangerous. It may be electrically charged from downed power lines or contaminated by oil, gasoline, bacteria, chemicals, or sewage, the Federal Emergency Management Agency website said.
FEMA advised walking on firm ground where water isn't moving and using a stick to check how solid the footing is because just 6 inches of shallow moving water can result in a person falling.
Flooded areas can still be risky after water recedes because roads might erode or weaken after a flood and the weight of a car could make them collapse, FEMA warned.
If the house is flooded and the main power switch is in a dry location, turn off the electricity, but if you have to wade into floodwaters, the Centers for Disease Control and Prevention advises calling an electrician.
Also, after extensive flooding, the foundation of your home may have weakened, so FEMA warns using extreme caution before entering.
Before being in contact with floodwaters, wear rubber boots, rubber gloves and goggles to avoid being injured by sharp objects, such as glass or metal, in floodwaters. Any injuries in contact with the dirty water could lead to infections.