Dysentery and cholera are only two of the diseases that are caused by people drinking dirty water.
But a team of students from Southern Colorado is working on a way to eliminate those diseases.
The method of water purification that they're working on earned them a grant from one of the most prestigious schools in the country.
Here in the United States we take water for granted. We can even get it from a vending machine.
But that's not the case everywhere.
"3.4 million people die every year from drinking dirty water," said Evan Dutch, a senior at Sand Creek high School.
Dutch is part of a team of students that is working on a way to change that with a simple filter.
Brody Strunk, a junior at Sand Creek said it's "what's called a biosand filter."
That's right: sand. The idea is for dirty water to be poured into a container filled with sand. After that, "It goes from sand to gravel," according to Grace Jiang, a senior.
Eventually the contaminants get stuck - at the microscopic level at least - to the sand. By the time that it reaches the bottom of the container and comes through a tube, it's 98 per cent pure. It sounds ingenious and it was enough to earn the team a grant from the Massachusetts Institute of Technology - and the admiration of their teacher.
"I'm super proud of this group because they've shown that they're capable of doing things that nobody ever would think of," said Todd Matia.
The Sand Creek High School students are part of Project Lead The Way engineering program, and one of 15 teams worldwide to receive the Lemelson-MIT Foundation grant. The grant will help the students to finish the project. It still has some bugs to work out.
Strunk said, "it's great at filtering the water. It's very inefficient in the output of the water."
But working on it has inspired this generation of budding scientists to consider pursuing careers in fields that will be important in the economy of tomorrow.
For Strunk his ideal job of the future is "a mechanical engineer."
For Dutch: "I want to end up working at CERN."
And for Jiang: "I'd be most interested in working in the petroleum industry."
It's the beauty of science, taking principles of something as complicated as fluid dynamics and turning it into something simple. Something that could one day save millions of lives.
But the work for the group is not done. They still need to raise $30,000 to finance the trip to MIT to make their proposal and to be able to deploy their filters in the field in places like the Philippines and Haiti.