The Tap Project, a UNICEF charity we’ve supported in the past, has a simple and elegant premise: If people paid one dollar for tap water in restaurants for a week, it would pay for a lot of clean drinking water in Third World countries. You can’t complain about the price — in New York, our tap water tastes better than a lot of brands that cost more. But UNICEF is looking for more participants to join the effort during World Water Week, March 16 to March 22. If you own or operate a restaurant, contact the Tap Project. You’ll be in good company: Participating establishments include Esca, Le Bernardin, and Gramercy Tavern.