Integrated Water Strategies for the Loom House

Project Description

Designed in 1968 by noted mid-century modern architect, Hal Moldstad, the Loom House is a 2,000-square-foot property on Bainbridge Island, an area where groundwater provides the only source of drinking water. Overlooking the Puget Sound, the property was originally comprised of a main and guest residence (known as the South House and the North House) linked by an outdoor patio. When the homeowners wanted to update the property and add a carport, they did so with a bold ambition: create a home that would restore the land it sits upon and become the first residential remodel to meet the requirements of the Living Building Challenge (LBC), the world’s most rigorous performance standard for buildings. They also wanted to do so affordably, using practices that could be replicated by others.

As the water consultant on a design team led by the Miller Hull Partnership, Biohabitats developed strategies to ensure that the site’s water infrastructure would respect the existing hydrology of the site while operating within a defined water budget. After developing a site water balance and collaborating with the client and design team, Biohabitats developed three water systems. A rainwater to potable system that collects and sends water from the roofs to an underground cistern, where it is filtered and disinfected in a mechanical room and pressurized for distribution throughout both buildings for all water demand (drinking, bathing, laundry and toilet flushing). A separate system harvests and directs rainwater from the carport roof into two above ground cisterns, where it is available for watering an adjacent garden. An onsite wastewater treatment system collects and treats all of the wastewater from the North and South Houses. The treatment system provides advanced treatment, using a recirculating textile filter, creating a high quality effluent that is distributed into the site landscaping, through a subsurface drip dispersal system.

The LBC requires that a building treat its own blackwater on site, but City policy required buildings within the sewer service area to connect to the sewer main. Undaunted by this challenge, and joined by members of the International Living Future Institute, the organization behind the LBC, the design team met with City officials and asked them to consider changing the policy. They shared plans for a modified septic system, designed by Biohabitats, which would provide additional treatment through a recirculating textile filter before dispersing effluent to a drainfield via drip irrigation. The City ultimately passed an ordinance allowing for onsite blackwater treatment, which enabled the project to move forward and opened the door for others on Bainbridge Island to employ an onsite wastewater treatment practice that could help replenish the aquifer, lessen the burden on the municipal sewer system, and help protect the Puget Sound. Loom House was the first renovated home to achieve LBC certification, and at the time of certification, was one of one four residences in the world to do so. It also received a 2021 Housing Award from the American Institute of Architects.