Donating $1 for tap water that is normally free helps UNICEF provide lifesaving water and sanitation to kids around the world.

"We raised about $2.5 million over the last five years of this campaign," says Stern. "Last year, we raised over $1 million for the first time. This year we’re hoping to top that."

Stern credits the continued success of the campaign to an army of volunteers who support the tap project and run fundraisers in their communities.

"In some communities, they are going just out to the restaurants making sure people support those restaurants," she says. "I’ve got a young girl who called me a couple of weeks ago who got involved. She went to see her school principal. She is a middle schooler. They have the entire school involved in what they call a water walk. The kids are going to carry a gallon of water all day. For every hour they carry it, they've got someone sponsoring that hour and they are collecting and raising money that way."

For the first time, the US Fund for UNICEF is also running a sweepstakes called "Celebrity Tap."

"We have UNICEF ambassador Selena Gomez along with Adrian Grenier, Dwight Howard from the NBA, singer Rihanna, country singer Taylor Swift and comedian Robin Williams. Each of them has filled a bottle with their own tap water from home and you can enter this sweepstakes to win one of those bottles," Stern says.

All the money raised by the tap project funds UNICEF's much-needed drinking water and sanitation projects around the world.