Residential Water Efficiency in the City of Los Angeles Understanding the Feasibility of Greywater Reuse Systems Research Question
Is the widespread implementation of greywater reuse systems a feasible option for increasing single family home water efficiency in the City of Los Angeles? What methods are available to facilitate the rapid adoption of greywater systems in existing and new single family homes?
How Greywater Works
Why Greywater?
Unprecedented drought conditions in Southern California. Statewide water conservation mandate of 20% reduction. Los Angeles longterm goals of 20% per capita reduction by 2017 and 50% by 2024. Up to two thirds of residential water consumption is used for exterior landscaping. the majority of residential water consumption is from showers and laundry machines, the main sources of water for greywater reuse.
LARC Framework for L.A.
Develops regional priorities for climate change resilience and adaptation. Strategies are then chosen to move the region toward achieving stated priorities. Greywater is evaluated here as a strategy to achieve water regional water resilience.
Initial Findings and Where L.A. is Now
Non-potable water from showers, baths, laundry, and sinks is diverted to a separate pipe
Los Angeles recently adopted a new streamlined greywater permit application with sample schematics and user friendly checklists.
Water must be applied through a subsurface system beneath a minimum of 2 inches of ground cover
Numerous rebates and incentives are available to Los Angeles residents for water efficiency and conservation (e.g. high efficiency plumbing fixtures and turf replacement). However, no such incentives exist for greywater systems.
Separation from harmful bacteria is essential No toilet water or water used for diaper washing Greywater may only be used for non-edible ornamental plants Diagram for Easy Permitting
Los Angeles residents use 180 gallons per capita per day. a household of four could reuse 250 gallons of wastewater (or fully 35% of household consumption) for landscaping purposes, removing the need to use potable water for outdoor use and lessening overall household consumption of potable water.
In Los Angeles, up to 250 gallons of greywater per day may be applied to landscaping
Recommendations Tie greywater system retrofits in with rebates and incentives for turf replacement (due to subsurface release requirement for greywater, this is the most cost effective time to install drip irrigation)
Methodology
per the LARC Framework, greywater systems for this project were analyzed based on the ability to move the region toward the priority of regional water security. the evaluation criteria used are feasibility, level of co-benefit to other priorities, regional benefits, financial and technological feasibility, role in regional adaptation and mitigation, and flexibility. Additionally, an evaluative review of greywater implementation in Australia and Arizona is used as precedent for arid regions utilizing greywater mandates and incentives to reduce water use. Credit: Clivus New England Incorporated
Poster.indd 1
Require greywater system infrastructure (diverter valves, plumbing connections, etc) for all new single family homes in the City of L.A. Require complete greywater systems for new homes with lawns or other water intensive landscaping Develop an ordinance similar to Tucson, Arizona that clearly identifies the benefits and opportunities of greywater systems for the City of Los Angeles Prepared by Zachary Andrews Faculty Chair Walker Wells 4/2/2015 1:13:16 PM