Both the FDA and the Red Cross recommend that you rotate your water every 6–12 months, depending on storage conditions. If you live in a dry climate, it will be more on the 12 months side. Water will also keep longer if you keep the tank in a cool, shaded area, like in a garage, shed, or basement. 

There are lots of options to treat your water. The best option that we have found is the one we sell here: view our water treatment kit. It extends the 6–12 month recommendation to 5 years, which makes things much more convenient. 

When it is time to rotate your water, hook a hose up to the bottom spigot and run it to a drain or a place that it can drain out, like a lawn or storm drain. Open the valve and let it empty. While the tank is empty is a good time to inspect it and decide if you want to clean it. A tank doesn't necessarily need to be cleaned every time you rotate the water.