Water rights by location, with priority dates

1,572,962 rights · 9 states · data from October 8, 2026

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Drop a pin to list every recorded water right within a mile, oldest first. Each one opens its full record and a link to the state's official file. Zoomed out, shaded circles show how many rights are clustered in an area; zoom in to see each one in its priority colour.

Priority date · senior to junior

  • Before 1880
  • 1880–1899
  • 1900–1919
  • 1920–1949
  • 1950–1972
  • 1973–1999
  • 2000 and later
  • No priority date

States on the map

Each state publishes its own water-right records, in its own format. These are the ones this map reads directly from the agency, refreshed weekly.

Not mapped yet

  • Washington — Ecology publishes rights and their diversion points in separate tables that have to be joined, and that join isn't built yet.
  • New Mexico — The State Engineer's public layer has no priority date or source name, and it carries owners' mailing addresses, which this site won't republish.
  • California — Most pre-1914 and riparian claims carry no priority date in the State Water Board's records, and California has no statewide groundwater-rights permit system to map.
  • Arizona — Surface-water filings and well registrations sit in two separate ADWR systems that mean different things, and most groundwater use is not a right in the appropriative sense.
  • Texas — TCEQ's mapped points carry no priority date, purpose or amount, and groundwater is governed by rule of capture and local districts rather than state rights.
  • North Dakota — The only bulk download is a legacy form that could break without notice, and permit pages can't be linked by permit number.
  • Wyoming — The State Engineer's surface-water diversion points aren't published in a machine-readable public form; only a groundwater copy about 18 months old is public.

Reading a water right

The short version of the terms on every record. Each state does it a little differently; the state guides cover the details, with links to each agency.

What does a dot on the map mean?

Each dot is a point of diversion: where the state's record says water is taken from a stream, spring, reservoir or well. It is not necessarily where the water is used, and a dot inside a property line doesn't mean the right belongs to that property. One right can have several points, and one point can serve several rights.

What is a priority date?

The date that sets a right's place in line. Depending on the state and the kind of right, it is when the water was first put to use, when a claim says use began, or when an application was filed. Older dates are senior; newer ones are junior. The colours on the map run from dark blue (oldest) to orange (newest).

First in time, first in right

This is the prior appropriation doctrine that governs surface water across most of the West. When a stream can't supply everyone, the most senior right gets its full amount before the next one gets any. In a dry year a senior user can “make a call”, and the state then orders junior users on that source to stop diverting. Seniority only matters among rights that draw on the same water, which is why each record links to the other rights on its source.

cfs, gpm and acre-feet

cfs (cubic feet per second) is a rate of flow: 1 cfs is about 449 gallons per minute (gpm), and running for a full day it moves almost 2 acre-feet. An acre-foot (AF) is a volume, enough to cover one acre a foot deep, about 325,851 gallons. A right usually caps both: how fast you may divert and how much in a year.

Surface water and groundwater

Streams, springs and reservoirs are surface water; wells draw groundwater. Most states on this map run both through the same priority system, but not all: Nebraska's groundwater is registered with the state and managed by local natural resources districts, without priority dates. Where groundwater feeds a stream, states may treat a well as part of that stream's line.

Exempt and domestic wells

Many states let a household drill a small well without a full water-right permit, inside limits that differ by state, and some of those wells still have to be registered or noticed. Utah has no such exemption at all. The limits for each state are on its guide page. A small well that was never filed won't appear on this map.