Chapter 173-135 WAC: Pasco Basin Groundwater Subarea

Ecology is starting a rulemaking for a new rule, Chapter 173-135 WAC for managing the Pasco Basin groundwater subarea, and repealing the existing interim management rule, Chapter 508-14 WAC.

This new rule is part of a multi-step process to address groundwater management in the Pasco Basin subarea. The project includes designating a groundwater subarea boundary as described in RCW 90.44.130, and establishing an agreement with the U.S. Bureau of Reclamation for allocating and managing groundwater in the area using our revised authority in RCW 89.12.170.

In 1967, Chapter 508-14 WAC established an interim policy for managing the commingled state and federal groundwater in the Columbia basin until formal management programs could be established for specific subareas within the basin. In the Quincy and Odessa subareas, jurisdiction over groundwater has been resolved and management programs established through rulemaking. However, in the Pasco subarea, groundwaters have remained under the interim rule despite numerous efforts over the past 50 years. 

In 2021, the Legislature revised Ecology’s authority in RCW 89.12.170 to enter into agreements with the U.S. Bureau of Reclamation for allocating groundwater. Under the new and pre-existing authorities, Ecology is proposing to develop a new rule for managing groundwater in the Pasco subarea and repeal the interim rule. This will address the longstanding uncertainty for current and potential future groundwater users.

Rulemaking timeline


Announcement phase (CR-101)

Filing date:
July 12, 2022

Announcement documents

Rule development phase

July 12, 2022 - Spring 2025

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