NAS Everett

Naval Station Everett

Rainwater Harvesting

Location: NS Everett, Washington
Owner: U.S. Navy

In 2011, Sain Engineering Associates (SEA) conducted an ASHRAE Level II energy and water audit at three sites located in Washington State. The first site was Naval Station Everett located outside of Seattle, Washington. It consisted of 22 buildings totaling more than 500,000 square feet. Two other locations at Naval Station Everett – Jim Creek and the Naval Station Everett – Smokey Point were also assessed, adding an additional 8 buildings totaling approximately 75,000 square feet.

The purpose of this assessment was to describe, measure, and identify as many cost-effective energy conservation measures (ECMs) as could be economically implemented. Due to the high precipitation rate of the area, it was determined that one such ECM would be to harvest the rainwater that falls at the facilities. SEA determined that assuming an 80% collection efficiency over 6,600,000 gallons of water could be collected annually. This water collection was to be used as a potable water backup system and provide an estimated annual savings of almost $60,000 per year.

SEA found that the average rainfall of the region was 37.54 inches per year and that the greatest potential for rainwater harvesting was during the month of November. Construction of the rainwater harvesting system was estimated to be $1.00 per gallon for above-ground storage space and $3.00 per gallon for below-ground storage. The collection potential for the month of November was used as the basis for tank sizing and for calculating the estimated implementation cost of approximately $1.4 million.

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