First in Time: How Western Water Rights Work

East of roughly the 100th meridian, water mostly belongs to whoever owns the riverbank. West of it, water belongs to whoever got there first and used it. That single difference explains a lot of Western politics, a fair number of lawsuits, and why a farmer with a creek running through his field may have no right to touch it.

The Western system is called prior appropriation. Miners in California and Colorado built it in the 1800s because riverbank rules made no sense in a dry country where the gold and the good farmland sat miles from the stream. You dug a ditch, took water, put it to work, and the date you started became your place in line. Idaho adopted the same idea and wrote it into the constitution it carried into statehood in 1890.

The four ideas that run the whole system

Priority

Every right carries a priority date. When there is not enough water, the oldest right gets its full amount first, then the next oldest, and so on down until the water runs out. The newest users get nothing. Nobody shares the shortage. The Idaho Constitution says it plainly in Article XV, Section 3: priority of appropriation gives the better right as between those using the water.

Beneficial use

A right exists only because water was put to a recognized purpose: irrigation, domestic use, stock water, industry, power, municipal supply and so on. Beneficial use is both the basis of the right and its measure. IDWR's own glossary says the amount of the water right is the amount put to beneficial use. Idaho Code 42-104 adds the other half: when the user stops using water for that purpose, the right ceases.

Property

A water right is real property. It can be sold, mortgaged, inherited and taxed in some settings. In most cases it is tied to a specific place of use, but it can be moved with state approval. That is why water rights show up in farm sales, bankruptcies and, more and more, in the paperwork for new industrial projects.

Use it or lose it

Because the right rests on use, nonuse can end it. In Idaho, Code 42-222(2) says a right is lost and forfeited after a failure to use it for five years. The party claiming forfeiture has to prove it by clear and convincing evidence, and section 42-223 lists situations where nonuse is protected. The director can also grant one extension of up to five more years if the holder asks before the five years run out and shows good reason.

Riparian law, the Eastern model

Riparian rights come with land that touches a stream or lake. Cornell's legal encyclopedia describes them as rights to reasonable use for domestic, farm and recreational purposes. California, which uses both systems, explains the key difference well: riparian holders take a correlative share, need no permit, and in a drought generally share the shortage among themselves rather than cutting off by date.

Riparian rights also tend to be limited to water that naturally flows past the land, used on land in the same watershed. You cannot usually store a riparian share in a reservoir for August or pipe it to a field over the hill. In a wet climate that works fine. In a desert it leaves most of the land dry.

Exceptions inside the priority system

Idaho's constitution adds limited preferences. When a stream cannot supply everyone, domestic users are preferred over all others, and agricultural users over manufacturing users, with mining in organized districts given its own preference. But the same section makes those preferences subject to the laws on taking private property, which means the preferred user has to pay for water taken from a senior. In practice, priority still runs the river day to day.

The other big exception is small domestic use. Idaho exempts small household and stock wells from the permit process, a topic covered in the next lesson.

Changing a right

Want to move a right from a field to a factory, or from a ditch to a well? Idaho Code 42-222(1) requires department approval to change the point of diversion, place of use, period of use or nature of use. The director can approve only if the change does not injure other water rights, does not enlarge the original use, and fits the state's conservation policy and the local public interest. Neighbors can protest and get a hearing.

That no-enlargement rule matters more than it sounds. A right that historically watered 80 acres for five months cannot quietly become a year-round industrial supply that consumes more water. The amount that moves depends on what was really used. People who skip this step end up saying that a company "bought water for 5,000 homes" when the state may approve a much smaller transfer.