Understanding Water Rights Using the Snake River as an Example

If you've ever stood beside a river and wondered, "Who owns all this water?" you're not alone.

The answer may surprise you.

In most western states, including Idaho, nobody actually owns the water flowing in a river. Instead, the water is considered a public resource held in trust by the state for the benefit of its citizens. What people, farms, businesses, and cities can own are rights to use that water.

Understanding how those rights work is essential to understanding many of the water challenges facing the American West today.

A Different System Than the East

In the eastern United States, where rainfall is abundant, water rights are often tied to land ownership. If your property borders a river or stream, you generally have certain rights to use that water.

The West developed differently.

As settlers moved into the arid western states during the 1800s, water quickly became more valuable than land itself. Miners, ranchers, and farmers needed reliable access to water, often miles away from where they lived.

To solve this problem, western states adopted a system known as "prior appropriation."

The basic principle became:

First in time, first in right.

Those who first put water to beneficial use gained legal rights to continue using it in the future.

The Snake River Example

The Snake River begins in Wyoming and flows across southern Idaho before joining the Columbia River in Washington. Along its journey, it supplies water to farms, cities, industries, hydropower facilities, recreation areas, and wildlife habitats.

Millions of acre-feet of water are diverted from the Snake River every year.

Farmers use it to grow potatoes, barley, wheat, sugar beets, corn, hay, and many other crops. Cities rely on it for municipal water supplies. Hydroelectric dams use its flow to generate electricity. Anglers, boaters, and outdoor enthusiasts depend on healthy river conditions for recreation.

Each of these users may hold water rights that specify how much water can be diverted, where it can be used, and what purpose it serves.

Today there are approximately 160,000 rights recognized to the water of the Snake River. The oldest senior water rights on the Snake River generally belong to irrigation users whose predecessors first diverted water in the late 1800s. Some rights date back to Idaho's earliest agricultural settlements, while tribal water rights may carry even earlier priority dates under federal law. Today, many of these historic rights are administered by irrigation districts and canal companies that continue to supply water to farms across southern Idaho.

Senior Rights and Junior Rights

Not all water rights are equal.

Under the prior appropriation system, older rights generally have priority over newer rights.

For example, a farmer whose family secured water rights in 1890 may have a senior water right. A subdivision built in 2015 may hold a much newer, junior water right.

During years when water is plentiful, everyone may receive the water they need.

During drought years, however, junior users may see their water deliveries reduced or even cut off entirely while senior rights holders continue to receive water.

This system can create difficult decisions, especially when growing populations increase demand for limited water supplies.

What About Fish and Wildlife?

One of the challenges of western water law is that many water rights were established long before people fully understood the importance of maintaining river ecosystems.

Historically, the focus was on diverting water for agriculture, mining, and development.

Fish require adequate stream flows and cool water temperatures. Wetlands depend on seasonal flooding. Birds and wildlife rely on healthy riparian habitats along riverbanks.

In many areas, conservation groups, government agencies, and local stakeholders are working together to balance human water use with the needs of river ecosystems.

**Is Your River a Person? **

Today, there is growing recognition that rivers themselves need water. In fact, in 2017 the Whanganui river in New Zealand became the first in the world to obtain "personhood", giving it some of the the legal rights of a person. Now the river has rights, among them the right to flow, maintain biodiversity, be free from pollution, and to sue. The Klamath River in Oregon (2019), the Magpie river in Canada (2022) and the Amazon river in Colombia (2018) and some of its tributaries (2023-2024) are also now benefitting from legal protections of personhood.

Why This Matters More Than Ever

As populations grow and snowpack becomes less predictable, competition for water is increasing throughout the West.

The Snake River Basin illustrates this challenge clearly. Agriculture remains a cornerstone of the region's economy, but communities, recreation, industry, and environmental interests all depend on the same finite resource.

When water supplies shrink, difficult choices become unavoidable.

Who gets water first?

How much should remain in the river?

How do we balance economic needs with environmental stewardship?

These questions will shape the future of western rivers for decades to come.

Rivers Need More Than Ownership

While water rights determine who can use water, they do not guarantee healthy rivers.

Clean water, healthy habitats, responsible stewardship, and sustainable management are equally important. A river can be legally allocated while still suffering from pollution, habitat loss, or reduced flows.

That is why protecting rivers requires more than understanding who has the right to use the water. It requires a commitment to preserving the rivers themselves.

At Clean Rivers Fund, we believe that healthy rivers benefit everyone—from farmers and communities to anglers, wildlife, and future generations. By supporting river cleanup and restoration efforts, we can help ensure that our waterways remain vibrant and productive long into the future.

After all, while no one may truly own the water flowing through a river, we all share responsibility for protecting it.

 

References and Further Reading

1. Idaho Department of Water Resources. Water Rights in Idaho. Explains Idaho's prior appropriation system, water rights administration, and beneficial use requirements.
2. Idaho Department of Water Resources. Snake River Basin Adjudication. Historical overview of the legal process used to determine and confirm water rights throughout the Snake River Basin.
3. United States Geological Survey (USGS). Water Science School: Water Rights and Water Use in the Western United States. Educational resources explaining western water law and water management.
4. Bureau of Reclamation. Snake River Basin Water Management. Information on reservoirs, irrigation systems, and water delivery infrastructure throughout the Snake River watershed.
5. Idaho Water Resource Board. State Water Plan. Long-range planning document addressing Idaho's water resources, conservation, and future demand.
6. Getches, David H. Water Law in a Nutshell. West Academic Publishing. A widely used reference on western water law and the doctrine of prior appropriation.
7. Tarlock, A. Dan. Law of Water Rights and Resources. Thomson Reuters. Comprehensive legal reference on water rights in the United States.
8. Te Awa Tupua (Whanganui River Claims Settlement) Act 2017. New Zealand legislation recognizing the Whanganui River as a legal person.
9. United Nations Environment Programme (UNEP). Rights of Rivers and Nature-Based Governance. Discussion of emerging legal frameworks recognizing rights of nature.
10. National Oceanic and Atmospheric Administration (NOAA). Healthy Watersheds and River Ecosystems. Resources on streamflow, aquatic habitats, and watershed management.

Related Reading

• The West's Water Challenge: When Snowpack Falls Short
• The Colorado River: Too Many Demands, Too Little Water
• Why Clean Rivers Matter
• The Hidden Cost of River Pollution
• How River Cleanups Improve Water Quality