We've all used them. Some people only occasionally to prepare for emergencies, and for others, they are a primary source of drinking water.
What's really going on with those big machines where we test our aim trying to get the stream of water into our plastic bottle?
Why do Supermarkets have Water Vending Machines?
To answer this question, I visited a company that sells them.
Here's what they said.
Water vending machines are a "no work" profit center for supermarkets. Hook it up, turn it on and watch the money roll in.
It's that simple, as there are no agencies or regulations that we could find who are responsible for the safety and inspection of these machines.
What's in that Big Box?
First off, despite the pretty sign on the outside saying "Glacier" or "Mountain Springs" the water in the machine comes from the same place as the water you wash with if you visit the supermarket bathroom.
Luckily there are filters in there too. They use a system called Reverse Osmosis, or RO filtration to remove virtually everything from the water.
The problem is, RO filters remove too much. They remove 95% of the minerals in the water, minerals that our body needs to be healthy.
And because water absent of minerals doesn't taste so great, some vending machines add flavorings, sweeteners and even artificial colors to improve the appeal of the water.
What Are We Getting Out of That Big Box?
While RO filtration can be a safe system they do need regular maintenance.
Prefilters in RO systems can become overgrown with bacteria. The RO membranes can become damaged and both of these could lead to serious problems.
Remember I said earlier; these machines are sold as "no work" profit makers to supermarket owners.
A group calling themselves the Environmental Working Group conducted independent tests of 247 supermarket water vending machines in California and concluded that expecting healthy water from one of these vending machines was about the same as expecting to win money from a slot machine.