Rainwater Harvesting for Potable Use at the Bertschi School

Living Building Challenge Full Certification v2.0 (All 20 Imperatives)

AIA National 2012 CAE Educational Facility Design Award

USGBC Best of Green Schools 2012

AIA Seattle What Makes It Green 2012

ED+C 2012 Excellence in Design

Sustainable Buildings Industry Council Beyond Green High Performance Building 2011

Design and Build with FSC Award 2011

Washington Association of Landscape Architecture 2011

American General Contractors Alliant Build America Award 2011

NAIOP Private Education Development of the Year 2012

Square Footage: 1425ft²

Washington State policy allows rainwater collection for beneficial use, however potable water sources are regulated by the Federal Safe Drinking Water Act.  Pursuant to federal law, state plumbing code (UPC Section 602) requires that all potable water be supplied from a municipal source in public buildings, or from an approved individual water supply source.  Individual sources must be treated with chlorine prior to use.   On the other hand, the Living Building Challenge 2.0 specifically forbids use of any chemicals on-site to treat water.  The Bertschi School designers opted to install the Carbon Filtration w/UV system.  Although Federal statute remains inflexible regarding this particular issue, potable water can be made available to Bertschi staff and students at the flip of a switch when and if regulations are updated to more accurately reflect the differences in the quality of particular sources.

Rainwater is collected from 3 roofs on the property: the butterfly roof, a small green roof, and some of the water from a nearby Church roof, which is channeled through rain leaders equipped with first-flush devices into an underground concrete cistern for potable water.  This cistern is treated with food grade Xypex Waterproofing, where it is stored prior to treatment with a UV light and carbon filtration System.  When operational, the treated rainwater can be pumped to potable water fixtures in the classroom, though currently it is physically isolated from the potable system due to Health Department requirement as mentioned above.  When the potable cistern reaches capacity of 2500 gallons, excess water is transported through an indoor/outdoor runnel to an irrigation cistern of 2750 gallon capacity , this water is used for irrigation water only.  The second cistern overflows into an outdoor rain garden, and then into a public storm sewer system as required.  However, so far no rainwater has been recorded overflowing to the storm sewer.

In keeping with The Bertschi School’s active learning environment, the Science Wing provides a living classroom and laboratory for students to learn first-hand about scarce resources such as clean water and air, and to see real solutions for protecting and conserving those resources.  In this case, rainwater flows through a clear-covered runnel runnel in the classroom floor which makes the flowing water visible during a rain event.  The curving concrete path of the runnel is decorated with art and inscriptions depicting water’s relationship to nature, wildlife, and us.  It flows through the lab and then outside where excess water is used to sustain the beautiful ethnobotanical garden.  This educational zero-impact landscape includes signage describing the garden’s diverse plant species, complete with QR codes which link students to each plant’s profile including scientific name, characteristics, uses and life cycle.

The Living Science Wing of the Bertschi school was the first “Living Building” in Washington state, a new addition to the school campus that also contains the first LEED-Gold LEED gold-certified building on an independent school campus in the Pacific NW (completed 2007).  It was designed through an intense collaboration between Bertschi students and staff, and KMD Architects’ Restorative Design Collective.  The team interviewed the students to find out what they wanted in their classroom, and heard: “an indoor river, a bamboo fountain to relieve stress, and green house where something’s always growing”. Architects, landscape architects, engineers, and other consultants paired these requests with the rigorous standards of the Living Building Challenge v 2.0 (LBC) to design a 1,425 sq ft science classroom building on a 3380 sq ft site with an ethnobotanical garden.

Since the time the project was built, Seattle King County Public Health Issued a policy statement #10-004 which facilitates the use of harvested rainwater to supply certain types of plumbing fixtures, including irrigation; and when used for irrigation, allows infiltration of overflow directly into the soil rather than requiring discharge the wastewater collection system

• U.S. Safe Drinking Water Act, CFR Title 40
• Uniform Plumbing Code (2006) Section 602.3
• Section 610 Disinfection