Home\Educate\Water Reuse 101\Research Projects\Year\2013\Treatment, Public Health, and Regulatory Issues Associated with Graywater Reuse

Treatment, Public Health, and Regulatory Issues Associated with Graywater Reuse

Project: 10-02
Type: Decision Making Tool
Year Released: 2013

Program: Principal
Funding Partner: Pentair Foundation
Total Investment: $66,667 (Cash: $50,000 In Kind: $16,667)

Principal Investigator:  Sybil Sharvelle, Colorado State University


There is a wave of new regulations that has promoted the use of residential graywater in single family homes to save water resources.  This new trend towards integrated graywater systems has left some states with questions on overall maintenance and safety of these systems due to many unknowns regarding the water quality of graywater, supplemental graywater treatment systems, and potential for public exposure to graywater reuse.  This project collects and integrates this knowledge on water quality, reliability of treatment systems, and regulatory parameters into a comprehensive tool.

Goals and Objectives

The objective is to gather useful data on the water quality, currently available technologies, and standards for integrating graywater systems into various types of localized sites. The data gathered would help those parties interested in making the necessary decisions about graywater reuse based on water quality and available technologies and standards.

Research Approach

This project performed the following to feed into the tool:

  • Collected currently available water quality data from graywater treatment technologies;
  • Surveyed the reliability of existing treatment technologies based on reviews of technology, other research efforts, and actual implementation results over identified lifetimes when technologies are maintained at various levels common to end uses;
  • Surveyed existing regional, state, and national codes and standards and whether the implementation and enforcement of these codes are effectively meeting water quality requirements and protecting public health; and
  • Surveyed international standards for any added information and guidance.Findings and Conclusions:
  • One of the barriers associated with graywater reuse is the difficulty sorting through the enormous quantity of information on graywater recycling that is available. Regulations on graywater reuse (state, national, and international) are inconsistent and water quality achieved by treatment technologies also varies substantially. Existing regulations and technologies need to be made easily accessible for interested parties. The Graywater Reuse Database (GRD) aims at addressing these issues by providing a simple identification of end application and regulations to summarize information and available technologies. A guidance manual accompanies to walk users through its use.

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