Net-Zero Water Usage Will Meet Water Petal Requirements of Living Building Challenge

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Water Petal of Living Building ChallengeAs the Preconstruction phase continues for the Chesapeake Bay Foundation’s Brock Environmental Center, one of the main natural resource conversations has been about water. There are over 783 million people across the globe without access to clean water, so the Living Building Challenge has dedicated an entire performance area, or “Petal”, to realigning how people (and buildings) utilize water.

The Living Building Challenge has seven performance areas, or “Petals.” We previously explained how the Brock Environmental Center will meet the conditions of the Materials, Site and Energy Petals. Now we turn our focus to the Water Petal of the Living Building Challenge and how the Center will meet these standards.

Living Building Challenge Water Petal

Water is a precious resource that is often taken for granted in the United States. The Living Building Challenge envisions a future whereby all buildings and communities are configured to harvest sufficient water to meet the needs of the population while respecting the land and ecosystems.

The Water Petal focuses on redefining “waste” in the built environment. With water in severe shortage in many countries around the world, it works to help limit the impact of buildings on this shortage by reusing water. The Water Petal has two requirements: net-zero water and ecological water flow.

1. Net-zero water requirement met with “rainwater collection system”

Rainwater collection system for Brock Environmental CenterAccording to the Water Petal, a project must have net-zero water, meaning one hundred percent of a project’s water needs must be supplied by captured precipitation or other closed loop water systems, or by recycling used project water. The water must also be appropriately purified without the use of chemicals.

The Brock Environmental Center will have a “rainwater collection system” to meet the net-zero water requirement. The slope of the building’s roof will funnel rainwater to a guttered collection system that drains and collects it in a 500-gallon wooden cistern located on the east end of the building.  The water collected in the cistern is then routed to the bathroom sinks for use in hand washing.  Signs over each sink will inform visitors that the water is to be used for hand washing only.  Since the restrooms will have composting toilets and waterless urinals, the rainwater collection system is the only water source required for the building.

Drinking water will be handled by the city’s water supply, and is equal to, or less than, the amount of water provided by the rainwater collection system — thus a net-zero water usage facility.

2. “Rainwater garden” will provide ecological water flow

The second step of the Water Petal is ecological water flow. One hundred percent of storm water and used project water discharge must be managed onsite (or an adjacent site) to feed the project’s internal water demands, leading to net-zero water. The water can be managed through acceptable time-scale surface flow, groundwater recharge, agricultural use or adjacent property needs.

The Center will have a “rainwater garden” to eliminate any runoff from the site into the polluted public storm water system that collects and treats water from streets, yards, driveways and parking lots. The garden, like the rainwater collection system, will utilize the slope of the building’s roof and the natural slope of the surrounding site to collect rainwater.


The garden will be excavated to be relatively shallow and then filled with a prepared soil and deep-rooted native plants and grasses that will filter the collected rainwater.  The captured filtered water then either percolates back into the ground, or is retuned to the atmosphere as water vapor through the plants’ process of transpiration.

If the Brock Environmental Center meets all of the requirements of the Petals, then it will be the first LEED Platinum and Living Building Challenge building in Virginia. Hourigan Construction continues to work hard in the Preconstruction phase to be sure the strict environmental standards are met so that groundbreaking can take place in August 2013.

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