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Rio Grande Watermaster Program

About the Rio Grande Watermaster Program, the area under its jurisdiction, and how to contact the office.

About the Rio Grande Watermaster Program

In the Rio Grande basin, above Amistad, water rights are managed as a “first in time, first in right” stream as they are in other parts of Texas. Water rights in the Middle and Lower Rio Grande are served by the Falcon-Amistad system. Water below Amistad is allocated on an account basis, much like having a bank account with a constantly changing balance. Priority is given to all municipal accounts so, at the beginning of each year, each municipal account’s storage balance is set to the authorized water-right amount. The municipal priority is guaranteed by the monthly reestablishment of a municipal reserve in the system of 225,000 acre-feet. That is equivalent to one year’s average diversions for all municipal demands below Amistad for Texas users.

Irrigation accounts, on the other hand, are not reset each year and must rely on balances carried forward. Each month, a determination is made as to how much unallocated water assigned to the United States is within the Falcon-Amistad system. If surplus water is identified, it is allocated to irrigation accounts on a monthly basis. When water is used, it is subtracted from the respective account by type of use from the account’s usable balance. This system of accounting for water usage was put in place after an international treaty with Mexico was established and in accordance with a district court ruling of 1969.

Rio Grande Watermaster’s Office

Rio Grande Watermaster
1804 West Jefferson Avenue
Harlingen, Texas 78550-5247
Voice: (956) 425-6010 or Toll Free: (800) 609-1219
Tall Fax: 956/412-5059


River BasinCounties
Rio Grande Brewster, Cameron, Dimmit, Hidalgo, Hudspeth, Jeff Davis, Jim Hogg, Kinney, Maverick, Presidio, Starr, Terrell, Val Verde, Webb, Willacy, Zapata

Offers to Sell or Contract Water in the Rio Grande

Currently there is no offer to sell or contract water. If you have any questions, please contact the Rio Grande Watermaster at (956) 425-6010 or toll free at (800) 609-1219.