After one too many nights in the nightlife business, Scott Harrison decided he needed to escape. These days, the nightclub and party promoter, who threw lavish after-parties for bands attending the MTV Video Music Awards and staged velvet-rope events for clients like Elle and Cosmopolitan magazines, is selling $20 water.

His bottles have turned up recently at Fashion Week, and 20-something women in matching black T-shirts can be found selling them in Manhattan’s parks.

“What’s in this stuff, anyway?” a woman recently asked as she passed the sleek display in Union Square Park.

Mr. Harrison recently formed a nonprofit group that is using a “charity: water” campaign to raise money to dig wells in some of Africa’s neediest countries. The sale of one bottle can buy someone 15 years’ worth of clean drinking water, he says.

After deciding he needed to check out of the city, Mr. Harrison, 31, joined Mercy Ships, a charity that runs hospital ships up and down the coasts of developing nations carrying doctors who perform surgeries. Mr. Harrison applied for the only job for which he felt remotely qualified: staff photojournalist. He eagerly paid $500 a month for the privilege of trading in his swanky New York life for a bunk bed and cafeteria food.

“I was living as a sycophant, a completely selfish existence,” he recently said. He had been hobnobbing with New York’s rich and famous and jetting off to Paris and Milan for hard-partying Fashion Weeks. Budweiser and Bacardi paid him to drink their brands exclusively. “I really had what I wanted, and I was miserable,” he said.

The ship traveled first to Benin on the west coast of Africa, then to Liberia, a country reeling from 14 years of bloody civil war. Mr. Harrison saw people whose blindness could have been prevented. He saw cleft lips and palettes. He saw tumors that had gone untreated for decades and had grown to the size of melons, distorting people’s faces and, in extreme cases, threatening to suffocate them. Harrison’s job was to take before-and-after photos of the patients.

On the ship, he had been warned: “When you go back, people won’t care.” Still, he said he couldn’t not tell his story. When he returned to Manhattan, he started by sending emails to his old A-list, the 15,000 or so people he used to invite to fashion parties. This time around, he was sending stories of graphic poverty, pictures of tumors.

Some demanded to be take off the list, but a surprising number offered to help.

“I just realized the power of images, and the power I could have talking about stuff I’d seen. Not dry stats, but individuals and communities that I knew intimately,” he says. “Just watching that stir people and connect them to the developing world was something I decided I wanted to do with the rest of my life.”

Mercy Ships, he decided, would get along without him. Mr. Harrison wanted to start something that would engage his friends.

Water was an easy choice for his first campaign. From his time in Africa, he knew the stats by heart: More than 4,500 children die each day from lack of safe drinking water and sanitation; unsafe drinking water kills more people each year than all forms of violence combined, including war.

He turned his recent birthday party into a “charity: water” event, and raised $17,000. This past week, he and his volunteers raised an estimated $19,000, and got pledges from schools and businesses to sponsor entire well projects.

To Mr. Harrison’s mind, this is just the beginning. He’s already talking with hotel chains and fitness clubs about selling the water. Next spring and summer, he hopes to have two water displays touring America and another in Europe. He’s begun dreaming up his next campaign — perhaps hunger, or AIDS, or education.

“Buy a $26 pencil and we’ll give someone school supplies throughout the year,” he says, testing out a possible pitch.