Water Savings and Financial Benefits Associated with Single-Family Package Graywater Systems

Graywater cover 3Planners, designers, decision makers, and researchers currently lack the information necessary to determine if graywater reuse systems are viable, safe, and provide cost-effective potable water savings.  At the same time, these professionals and other stakeholders are increasingly under pressure to promote and/or incentivize the use of single-family packaged graywater reuse systems. Recognizing this dynamic, the AWE Research Committee wanted to develop a resource that would help industry professionals perform cost-benefit analyses for single-family packaged graywater systems.

The report includes easy-to-follow steps for determining the cost-benefit ratio, which gives utilities justification in choosing to include or exclude graywater systems from their program offerings.  These specific issues, among others, are also addressed: 

  • Currently available single-family packaged graywater reuse systems
  • Currently costs associated with these systems
  • Currently return on investment periods
  • System life-cycle
  • Actual potable water savings and the variability of savings over time
  • Monetary savings for the customer and utility
  • Return on investment timeframes
  • The potential impact of variables such as climate and weather variability

The report emphasizes that the results of a cost-benefit analysis will vary from utility to utility, but does set out some guiding principles that are the same everywhere.  Specifically, it finds that graywater reuse programs are better suited as long-term, ongoing programs, and that several variables, such as long irrigation seasons and high home occupancy rates, impact the potential for customer savings.  It also stresses the fact that the volume of water savings achieved via the use of a graywater system is not equal to the volume of graywater generated or collected—It is equal to the volume of potable water savings achieved by the homeowner.

Click here to download the full report.

Click here to download the full report (Canadian Version).

Click here to download a fact sheet. 

A unit cost comparison is another resource developed for this project. Click here to read more about unit cost evaluations across the U.S.

More information on Graywater Systems can be found on AWE’s Resource Library pages for Graywater Introduction and Graywater Recovery and Treatment Systems.

This report was made possible with funding from the East Bay Municipal Utility District and the Portland Water Bureau, and with grant support from the California Department of Water Resources.