Reclaimed Water Evaluation

The North Seattle Reclaimed Water Project Economic Analysis examines the financial, environmental, and social costs and benefits of delivering reclaimed water to customers in the North Seattle area. For the analysis, SPU used a framework developed by the WateReuse Foundation for applying standard benefit-cost analysis tools to the evaluation of reclaimed water projects. It identified three primary objectives of this reclaimed water project:

  1. Improving water quality in Puget Sound
  2. Improving local stream conditions in the North Seattle/Shoreline area
  3. Augmenting Seattle’s potable water supply

Project benefits were quantified in physical rather than monetary terms, and alternative means of attaining them were identified. Total life cycle costs for the project and its alternatives were estimated to determine whether the project or one of the alternatives would provide the desired benefits in the most cost-effective manner.

The overall conclusion of the analysis was that the proposed North Seattle Reclaimed Water Project would not be a sound investment for the region due to high costs, a low level of benefits, and the availability of lower-cost alternatives for achieving comparable benefits. Specifically, it was found that the high costs of building a purple-pipe distribution system to serve a large number of relatively small customers, dispersed over a large area, made the project cost-prohibitive. If the goal is to improve water quality in Puget Sound, increasing the level of treatment at existing wastewater treatment plants is one alternative that turns out to be much more cost-effective.

Report Summary (pdf)
Full Report (pdf)
Separate Appendices (pdf)
Two Page Overview (pdf)