McAllister Wellfield

Olympia's Main Water Source

Olympia will move its main water source from McAllister Springs to a new Wellfield in the Spring of 2014.The City of Olympia is committed to providing safe and reliable drinking water to its customers — now and into the future. In order to meet this commitment, the City developed a new water source which replaced McAllister Springs as the City’s primary supply of drinking water. The City began using the Wellfield as it's main water source in November 2014. The new water source, named the McAllister Wellfield (view site map), is significantly more protected, more productive, and will meet water supply needs for generations.

Why replace McAllister Springs?
The City relied on McAllister Springs for more than 60 years. Located at the headwaters of McAllister Creek, McAllister Springs, while continually providing high-quality water, is vulnerable to potential contamination, and would have required extensive treatment if not retired.

Moving to a Wellfield
In the 1990s, after extensive research, the City identified and purchased 20-acres for a wellfield.  Studies of the site show that the wellfield site taps a large sustainable aquifer with high quality water.  The site, called McAllister Wellfield, is up-gradient, and approximately a mile southeast of McAllister Springs.  With the purchase of the site and 100-acres of adjacent development rights, the City began the long-term process of developing McAllister Wellfield into our primary source of drinking water.

For years, the City worked closely with other agencies and municipalities to plan for development of the McAllister Wellfield. Construction began on August 13, 2012.

A Historic Partnership
In May 2008, the City and the Nisqually Indian Tribe entered into a historic agreement - the first such agreement between a tribe and a municipality in the country - to jointly develop a new regional water source at McAllister Wellfield. Once the project is complete and operational, the wellfield will provide a secure supply of water for both communities for generations to come.

Transfer of Water Rights
On January 3, 2012, after working together for many years to gather data, refine computer models and predict potential impacts, the Department of Ecology presented the Olympia City Council with the final approval for transferring water rights to the new wellfield.

Wellfield Construction Process

Construction of the McAllister Wellfield is finished, and consisted of three individual projects.

McAllister Transmission MainConstruction of nearly one mile of 36-inch diameter pipeline to connect the new Wellfield to the City’s existing water transmission main at McAllister Springs.

Schedule: Project completed

Cost: $5.4 Million

Funding: Drinking Water Utility, largely with low-interest loans from the Washington Drinking Water State Revolving Fund.

McAllister Wellfield renderingConstruction and testing a series of wells, installing associated pumping equipment, chlorination, motor control equipment, and a generator, all housed in buildings on the 20-acre McAllister Wellfield site.

Schedule: Project completed Fall 2013-November 2014

Cost: $8.3 Million

Funding: Drinking Water Utility, largely with low-interest loans from the Washington Drinking Water State Revolving Fund.

Corrosion Control FacilityConstruction of a Corrosion Control Facility which uses aeration (a non-chemical treatment approach using blown air) to raise the pH of water and reduce potential pipe corrosion. Corrosion of household piping can cause lead and copper to leach into the water. The federal Safe Drinking Water Act requires the City to take action to raise the system pH to an optimum level to prevent pipe corrosion.

Schedule: Project completed January 2017 - April 2018

Cost: $3.4 Million

Funding: Drinking Water Utility Capital Fund