People in Trenton and surrounding towns are being urged to conserve water.

Trenton Waterworks put out an advisory Wednesday night asking customers to use water only for essential reasons or emergencies.

The utility said the action is needed because of fragile ice buildup in the Delaware River, which is the capital city's main raw water source.

Frazzle Ice is a collection of small ice crystals that form in water while it's still moving.

When temperatures drop below freezing and it's notorious for blocking water intakes, effectively shutting down operations at the Trenton water filtration plant, a spokesperson for the city says there are still plenty of safe drinking water while the plant is offline.

That's thanks in part to the Pennington Avenue Reservoir, which is designed to store 100 million gallons of treated water or about a three day supply for the system.

There's also an emergency interconnection with the nearby New Jersey American Water that's been activated while the city works to bring the water plant back online.