If you have access to clean water, you probably don't think twice about it, at least not on a daily basis. We hardly ever think about what it would be like not to have clean water — we turn on the tap at home, grab a bottle after a long run, and barely even notice when the waiter comes to refill our water glass. But for millions of people, having access to clean water isn't a sure thing.According to UNICEF, roughly 663 million people worldwide don't have access to clean drinking water, while 2.4 billion people across the globe don't have access to sanitation facilities. Almost 1,000 children die every day because of illnesses caused by a lack of clean water, which is one of the leading causes of death for children younger than five years old, UNICEF notes But helping people around the world get clean water doesn't have to be complicated. In honor of World Water Day on March 22, the UNICEF Tap Project is raising money to help provide clean water to children and families. The organization says just $15 can help provide a year of clean water.You can donate the traditional way here , scroll down the page, or you can take UNICEF's unique challenge: by visiting their website on a smartphone, and then not using your phone for just five minutes, you'll unlock a donation from Giorgio Armani Fragrances and S'well that's equivalent to the cost of water for one day for a child in need. Both companies are also offering donations to UNICEF from the sales of their products this month.Want to see the impact you're making by donating your time and money? Ahead, UNICEF shares striking images of refugee families whose lives have been changed by access to clean water.Editor's note: All photos and captions were provided by UNICEF.