Nearly 780 million people worldwide do not have access to a source of clean water (water that flows through a household connection, borehole, well, or protected spring).

In the US, 99.2% of the country has access to clean tap water , but many contamination.

contamination. Bottled water and clean tap water are virtually identical in terms of purity and taste. In a 2011 study, only one-third of blind taste-testers could correctly identify tap versus bottled water.

Unlike tap water, however, producing bottled water is an expensive, resource-heavy process that requires crude oil and extra water.

There's nothing quite like the feeling of a pure, ice-cold drink of water.

While some Americans get water from the tap, the rest pay for the bottled variety — at a cost of $100 billion a year.

The average cost of a gallon’s worth of single-serve bottled water in the US is nearly $9.50, according to FoodandWaterWatch. That's nearly three times more expensive than the average price for a gallon of milk, and almost four times the average price for a gallon of regular gasoline. Bottled water costs nearly 2,000 times more than tap water, which costs less than a cent per gallon.

Many people assume that the higher price tag is justified by the health benefits of bottled water, but in most cases, that's not true.

This year's World Water Day falls on March 22 — the day is meant to draw attention to disparities in clean-water access around the globe. Worldwide; 780 million people don't have access to a source of clean water.

But for the vast majority of Americans, tap water and bottled water are comparable in terms of healthiness and quality. In some cases, publicly sourced tap water may actually be safer, since it is usually tested more frequently, Plus, bottled water is more likely to be contaminated by microplastic particles than tap water.

"It is wrong to assume that bottled water is somehow cleaner, healthier, or safer than tap water in the US," Peter Gleick, an environmental scientist and the co-founder of the Pacific Institute, told Business Insider.

There are exceptions, however: Water that comes from people's private wells do not see the same rigorous testing as those whose water comes from public sources. And, as was the case Flint, Michigan, some public sources are not properly screened.

Nonetheless, there are plenty of reasons for most people to stop shelling out for bottled water. Here's what to know.