It’s World Water Day today — though we believe every day should celebrate and honor Earth’s most precious resource. Since 1992, March 22 has been an international observance of the importance of clean water for a healthy world. Today, we spotlight three smart projects that actually do something about the cause and offer ways in which you too can help.

TAP PROJECT

In 2008, Tap Project topped our list of the year’s best ideas. We still think it’s one of the simplest, smartest efforts to both raise awareness about water sustainability and make an actual, action-based difference.

Developed in partnership with UNICEF, the project’s premise is brilliantly simple: During World Water Week March 21-27, restaurants would ask patrons to donate $1 for each glass of tap water that they normally enjoy for free. It may seem like little, but $1 actually provides clean drinking water for a child for 40 days — which means less than $10 get a child a year’s worth of water. All donations go to UNICEF’s water sanitation programs that strive to bring clean, accessible drinking water to children around the world.

The one million restaurants across the US comprise the second largest industry in the country, following government. Thousands of them are participating in the program this week — up from 300 in 2007, when the project launched. So imagine the scale of impact of these micro-contributions, a powerful long tail of goodness.

This year, Tap Project is launching Tap Project Radio — a platform for musicians, artists, directors and thought leaders to play music, raise awareness and help fight the water crisis. From performances by Kenna, They Might Be Giants and other indie favorites, to interviews of advertising legends Lee Clow and David Droga (who founded Tap Project in 2007), the lineup is an absolute treat.

You can help in one of three ways: Dine at one of the participating restaurants and buy yourself some tap water; donate directly to the project; or text Text “TAP” to UNICEF (864233) to donate $5 and give a child 200 days of clean drinking water.

Have a restaurant or know someone who does? It’s not too late to register and join the effort.

CHARITY: WATER

Also in 2008, we featured just-launched nonprofit charity: water — a fundraising effort to bring clean drinking water to people in the developing world. Since then, the project has become such a blockbuster success — from getting press in just about every major media outlet to being the beneficiary of last year’s Twestival — so we won’t elaborate on what it’s all about.

Today, charity:water is launching Unshaken — a concentrated effort to help Haiti recover by providing long-term water solutions in a country where a third of the population didn’t have access to clean drinking water even before the disaster. The plan focuses on 11 specific areas that need funding. For each of them, the charity: water team has worked hard to calculate the exact costs and collected real-life stories from the community about how that particular issue affects their daily lives.

The goal is to raise $1.3 million, helping 40,000 people in dire need. Bring them a wee closer to it by donating today.

PUR

At TED last month, we were excited to see PUR’s drive to donate 10 liters of clean drinking water for every tweet that answered the question, “If water could speak, what would it say?” and every photo answer at the TED photo booth. The program was a smash-hit, with more than 800 plastic bottles saved over the course of the four days and over 40,000 liters of water donated by PUR.

For World Water Week this week, PUR is doing another round under the Children’s Safe Drinking Water program — for each new Facebook fan, they’re donating 100 liters of clean drinking water to the areas that need it the most, up to 1 million (yes, million) liters total. So do your part and fan PUR to give a child this basic human right.

And, shhh, a little birdie told us PUR will be having a bunch of giveaways this week, so follow them on Twitter for a shot at the goodies.