The News: Affordable Housing Developer Finds Big Benefit in Water Reuse

With at least 36 states anticipating local, regional or statewide water shortages by 2013, the potential for water reuse is rising in importance. Indeed, population growth and climate change are only likely to exacerbate the problem. To that end, Central City Concern, a Portland, Ore.-based non-profit affordable housing provider, in March released a study targeted at determining whether development and maintenance of affordable housing projects can be helped by encouraging water reuse. Central City Concern and partners SERA Architects, Interface Engineering and Gerding Edlen Development Co. wanted to achieve water independence at an affordable housing project, the Pearl Family Development. The approximately 175-unit the project has now been put on hold due to shortfalls in government funding at the federal and local level. However, Central City project manager & architect Ben Gates said he hopes the project will be restarted soon. Three types of water can be reused: rainwater; greywater, which is wastewater generated from hand-washing, clothes-washing and bathing; and blackwater–water contaminated by human body waste, food residue, chemicals and solvents. The Central City-led group determined that greywater harvesting would be needed to meet most, if not all, needs in a multi-family building, which typically has high water demands. Treatment costs vary by type, with rainwater the least expensive, greywater next and blackwater the highest.A typical scenario would reuse rainwater for drinking, greywater for flushing toilets and washing clothes, and treated blackwater, where no human contact occurs and lower water quality is acceptable, for toilet flushing and sub-surface irrigation of landscaping.    Many municipalities require that a building be connected to a municipal water system to ensure sufficient water availability in case of an emergency, such as a fire. Backup water could also be useful in case the building’s water treatment systems failed, Gates said. But achieving water independence can engender significant cost savings, particularly important in an affordable housing development. The group projected rain and greywater harvesting would cut water costs by 30 to 40 percent. Adding water-efficient fixtures, such as dual-flush toilets, could cut water costs by 60 to 70 percent annually.Water and sewer rates increased by 8 percent from fiscal year 2008 to 2009 in Portland, with rates forecast to rise by 10 percent annually over the next five years, the study noted. The average Portland household spends more than $800 annually on water and sewer utility costs. For a family earning minimum wage, that translates to approximately 5 percent of their disposable income. “To keep an affordable housing development affordable, utility costs have to be controlled and reduced,” Gates said.