:


John,

When you think about clean water, forests probably aren't the first thing that come to mind.

But across the country, wild forests play a quiet, essential role in protecting the water we drink and the rivers, lakes and streams we rely on.

Trees help generate rainfall, filter pollution before it reaches waterways and reduce harmful runoff that can contaminate drinking water and fuel algal blooms.[1]

But how exactly do forests help keep our water clean and flowing? And what happens when those forests are lost or degraded? Here's what you need to know:

Forests don't just stand passively around rivers and reservoirs. In fact, they help drive the water cycle that keeps these waterways full.[2]

Trees and other plants actually release the water they absorb as water vapor back into the atmosphere, returning a large share of the precipitation that falls on land back to the sky.[3]

Forests also help water soak into the ground instead of rushing off the surface. Roots and forest soils act like a sponge -- absorbing water, resupplying groundwater and supporting a healthy and stable water table.[4]

But when forests are degraded, these natural processes are disrupted, potentially impacting the water cycle.

Forests also act as a frontline defense against pollution.

On unforested land, rainfall can create fast-moving runoff that picks up dirt, fertilizers, pesticides and other contaminants, carrying them into nearby waterways. But in forested areas, vegetation and roots trap pollution and absorb contaminants well before they reach streams and reservoirs.

Some studies show that vegetation can filter up to 90% of sediment carried by runoff.

This natural filtration system protects both people and wildlife. Sediment pollution can raise water treatment costs, worsen flooding, and harm fish and other aquatic critters by clogging gills, suffocating eggs and reducing photosynthesis.[5]

Across the United States, forests play a major role in protecting our drinking water supply.

A U.S. Forest Service analysis found that 89% of public surface drinking water supplies receive at least some surface water from forested lands.[6]

That means forests help filter the drinking water of roughly 150 million Americans.[7]

Some western cities, like Portland, Oregon, receive up to 90% of their drinking water from nearby national forests.[8]

In other words, preserving forests helps keep our water clean and reliable.

America's forests are facing increased threats from logging, mining and roadbuilding.

Once these landscapes are degraded, their ability to store water and filter pollution can be diminished for years, and rebuilding those natural safeguards can take decades.

That's why we're working to protect our wild forests from unnecessary destruction and keep watersheds intact, so communities can count on clean water for generations to come.

Recently, Environment Colorado supporters, alongside our allies and coalition partners, helped deliver upwards of 600,000 petition signatures urging the U.S. Forest Service not to rescind protections for our wild forests.

And we'll keep working to ensure that the trees, forests and landscapes that help provide us with clean, clear water remain intact for years to come.

Thank you for standing with our wild forests,

Ellen Montgomery

P.S. Protecting forests today helps protect clean water tomorrow. Please consider supporting our work to keep our forests standing.
[link removed]

1. Vincent Cotrone, "The Role of Trees and Forests in Healthy Watersheds," PennState Extension, August 25, 2025.
[link removed]
2. Ellen Montgomery and Rylee Shear, "America's Oldest Forests and Clean Drinking Water," Environment America Research & Policy Center, February 22, 2025.
[link removed]
3. "Evapotranspiration and the Water Cycle," U.S. Geological Survey, June 12, 2018.
[link removed]
4. "Evapotranspiration and the Water Cycle," U.S. Geological Survey, June 12, 2018.
[link removed]
5. Luke Metzger and Drew Francis, "How Texas forests protect our water supply and improve water quality," Environment Texas Research and Policy Center, July 21, 2025.
[link removed]
6. Ning Liu, et. al., "Forested lands dominate drinking water supply in the conterminous United States," U.S. Forest Service, July 22, 2021.
[link removed]
7. Ning Liu, et. al., "Forested lands dominate drinking water supply in the conterminous United States," U.S. Forest Service, July 22, 2021.
[link removed]
8. Cynthia West, "New Research Reveals How Critical Forests are to Drinking Water Supply," U.S. Department of Agriculture, October 4, 2022.
[link removed]




-----------------------------------------------------------

Your donation will be used to support all of our campaigns to protect the environment, from saving the bees and protecting public lands, to standing up for clean water and fighting climate change. None of our work would be possible without supporters like you. Environment Colorado may transfer up to $50 per dues-paying member per year into the Environment Colorado Small Donor Committee.

-----------------------------------------------------------

Join us on Facebook: [link removed]
Follow us on Twitter: [link removed]

Environment Colorado, Inc.
1543 Wazee St., Suite 400, Denver, CO 80202, (303) 573-3871
Member questions or requests call 1-800-401-6511.
If you want us to stop sending you email then follow this link: [link removed]