Eco-friendly House Uses Rainwater Harvesting System

The Sunset Monterey Bay Idea House in Monterra, Calif., is 20th in a line of exceptional custom homes presented by Sunset magazine to showcase product innovation, architectural, landscaping, and decorating ideas. The house was designed to meet Monterey County "green" building specifications as well as Sunset's expectations for its Idea Houses.

"The county encourages green construction by expediting permits and offering other incentives," said Tom Messenger, of Messenger Construction Management Inc., who served as project manager. "The Sunset Monterey Bay House needed to be at least 70 percent green through the use of environmentally innovative features such as the ability to reclaim water."

Triton Stormwater Solutions was selected as the water solution provider, explained Bill Wilson, an environmental consultant with Carlile Macy, who assisted on the project. "Triton enables you to put a large amount of storage in a smaller area with less cover and that makes it really competitive economically."

The Monterey Peninsula has always had issues with a lack of water, and there have been recent concerns that volunteer water rationing may become mandatory. In addition, California regulation states that the footprint of a building dictates the number of bathrooms allowed in a house based on water availability. Harvesting rainwater offers homeowners the ability to have an unlimited number of bathrooms.

A Triton detention system was installed that allows for the harvesting of rain and stormwater to be re-used as a "gray water" source for toilet flushing, car washing, and irrigation purposes. The 49-feet-long by 34-feet-wide excavation contains 65 chambers that hold 20,000 gallons--enough to water the entire half-acre landscape area for one year.

First, workers dug a hole and then installed and compacted a base layer of rock according to the soil engineer's requirements. Next, workers lined the bottom and walls of the trench with a class 2 nonwoven geo-fabric and installed a custom-made liner and more geo-fabric.

Workers then could installed the chambers, manifold, and standpipe connection and begin to backfill the trench with embedment stone. Once this backfill process achieved a consistent cover of 6-inches of stone above the chamber crowns, then workers folded the geo-fabric over the embedment stone and installed the finish grade fill. Two dump truckloads of fill stone were dumped onto the chamber bed and leveled with a backhoe maintaining 8-inches of cover between the wheels and the top of the embedment stone. The finished stone was then compacted per the specification, and the Triton system was ready to accept traffic loading of H and HS 30.

The total installation, including digging, placing the chambers, and covering with soil took two days, although that was due in large part to ensure the stability of the soil while following stringent California requirements as a result of the large number of earthquakes in that region.

The Monterey House is tentatively scheduled to be open in October and featured in Sunset magazine's October issue.

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