Overall Rating Gold - expired
Overall Score 68.55
Liaison Daryl Pierson
Submission Date Feb. 11, 2011
Executive Letter Download

STARS v1.0

Portland State University
Tier2-3: Non-Potable Water Usage

Status Score Responsible Party
Complete 0.25 / 0.25 PJ Houser
Office Assistant
Campus Sustainability Office
"---" indicates that no data was submitted for this field

Does the institution use non-potable water (e.g., harvested rainwater or graywater) for irrigation and/or other applications?:

A brief description of the source of non-potable water and how it is used:

*Associated Students Recreation Center (LEED Gold)*
Rain is harvested on the 5th floor and is collected in a holding tank on the first floor for use flushing toilets.

*Epler Hall Rainwater Harvesting System*

PSU's Epler Hall is a mixed-use LEED Silver building featuring an innovative rainwater harvesting system that diverts 26% of stormwater from Epler and the neighboring King Albert Hall. Rain that collects on the buildings' rooftops is directed to several disconnected downspouts that empty into raised river rock beds located in a public plaza. Water flows through the plaza via a series of planter boxes and carved stone channels, emptying finally into underground retention tanks. The water is filtered through a sand trap and treated using ultraviolet light before being pumped back into Epler for use as flush water in first floor restrooms and landscape irrigation. This system reduces the building's annual demand for municipally treated potable water by approximately 110,000 gallons/year, saving the University nearly $1,000/year in wastewater expenses. PSU was awarded a 2005 BEST Award for its innovative Epler rainwater harvesting system.

*Engineering Building Hydrology Lab*

Portland State University's newest building, the Northwest Center for Engineering, Science and Technology, is equipped with a rainwater harvesting system that uses Oregon's average 38" of annual rainfall to supplement the building's overall water demand. The system captures rain from the rooftop and diverts a portion through the rainwater harvesting system located in the hydrology lab on the 2nd floor. The water is stored in a 1000 gallon storage tank, filtered through carbon, and undergoes UV sterilization before being pumped to toilets and urinals on the 1st floor. In addition to conserving flush water and reducing rainwater runoff, this system also contributes to the university's engineering curriculum. Students use the rainwater harvesting system to study water usage rates, savings, filtration methods, and other aspects in an effort to advance this technology.


Epler Hall is a mixed-use classroom and dormitory building that moves rainwater from the roof and plaza to a ground level water feature before collecting it to flush seven first floor toilets and irrigate the landscape. The system is expected to reduce the building's annual demand for municipally treated water by 110,660 gallons and associated annual costs by approximately $980.

The website URL where information about the program, policy, or practice is available:
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