​​Never assume that water in the backcountry like water from lakes, streams, rivers, or springs, is safe to drink.

Use only boiled, treated, or bottled water for:

• drinking
• preparing food
• washing dishes
• brushing your teeth

The best way to make sure your backcountry water is clean and safe is to filter it first, then boil it for at least 1 minute. Boil your water for 5 minutes if it is cloudy or has debris in it.

If you can’t boil your water, filter it first and then use chemicals like iodine or chlorine to make it safer. As a final step, use an ultraviolet (UV) light if you have one.

Learn more about how to make your drinking water safe when you can't boil it.

Water filters

Portable water filters clean water by forcing it through a very fine strainer (mesh). This can trap germs that can make you sick, like bacteria, parasites, and viruses.

The holes in the filter are very small, measured in microns. It’s important to get a filter that has the smallest holes in the mesh as possible. Make sure your filter is 1 micron absolute or smaller.

Don’t rely on a water filter alone. After using a filter, boil your water or use chemicals to make sure it’s safe to drink.

Boiling water

After you filter your water, boil it for at least 1 minute. If the water is cloudy or has debris in it, boil it for at least 5 minutes.

Let the water cool to a safe temperature before you use it.

Chemicals

If you can't boil your water, filter it first and use chemicals to make it safer. Use chlorine and iodine to kill bacteria and viruses. These chemicals won’t kill all of the parasites. Boil your water to make sure it’s safe to drink. Learn how to make your drinking water safe when you can't boil it.

Ultraviolet (UV) disinfection pen

UV light can help make water safe by killing germs. It will only work if your water is very clear. It will not work if your water is cloudy or has floating debris.

Before you use a UV disinfection pen, let your water sit for a while so that any small particles (sediment) have time to settle. Follow the directions for your UV disinfection pen exactly.

Don’t rely on a UV disinfection pen alone. You also need to use a water filter and to boil your water or use chemicals to make your water safe.

You can buy UV disinfection pens at some camping stores.