If you hike or backpack in areas with large amounts of decaying vegetation, like the forests of North America, you’re going to come across natural water sources that are sickly red, orange, or yellow. The tea-like coloring is caused by tannins that have leached from trees, grasses, and leafy plants into the local water supply. This coloring is harmless, and the water can be filtered or purified by regular means for human consumption. While it’s aesthetically displeasing and may impart a slight bitterness to the water, tannins do not pose a health or medical issue.

Some water filters can partially remove tannins from reddish water, particularly those with an activated carbon component, such as the Katadyn Hiker Pro, thereby making the water more palatable. The MSR MiniWorks Ceramic Filter can also remove tannins, but must be brushed (cleaned) occasionally to restore its normal flow rate. However, tannins will reduce the lifetime of most hollow fiber filters, such as the Sawyer Squeeze, the HydroBlu VersaFlow, and the Katadyn BeFree, unless they are backflushed more frequently.

More Frequently Asked Questions

• Ultraviolet Water Purification 101
• Cold Weather Water Treatment and Purification
• How Much Water Do You Need for Day hiking?
• How to Prevent your Water Filter from Freezing in Cold Weather
• Hiking and Backpacking Hydration Systems: Pros and Cons

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