Graywater Recovery and Treatment Systems Introduction

Graywater is generally defined as untreated wastewater that has not come into contact with toilet waste, kitchen sink waste, dishwasher waste or similarly contaminated sources . Graywater includes wastewater from bathtubs, showers, and bathroom wash basins, clothes washers and laundry tubs.  This includes graywater from both residential and non-residential installations.

The capture, treatment, and reuse of graywater not only yields usable water that would otherwise be directed to the sewer, its use on the landscape and for car washing is generally not subject to the typical watering restrictions that are sometimes imposed by local jurisdictions.

In the search for and development of new water-efficient technologies for home and business, firms throughout the developed world have focused on a variety of graywater treatment technologies. These approaches to treated graywater applications have divided themselves into two distinct categories:  engineered systems and package systems.  Characteristics are generally as follows:

Engineered Systems

•  Project-specific design - tailored to need
•  Large projects and buildings where package systems would not be suitable

Package Systems

•  “Off the shelf” systems – ready for installation
•  Wide application - not project-specific
• Small and large projects

This page is directed exclusively at package systems, although some of the impediments described below may also be applicable to engineered systems. Today, these significant impediments to widespread installation of graywater recovery and treatment systems include, but are not limited to, the following:

  1. Restrictive health and safety codes and standards, which are inconsistent in their requirements and application throughout the various state and local jurisdictions in North America;
  2. Product and installation costs, which are somewhat unknown due to the evolving system technologies and the varying applications within buildings; and
  3. System maintenance requirements and who will fulfill them.

Product Standard

The National Sanitation Foundation (NSF) developed and published product standards NSF/ANSI 350 for water reuse treatment systems. With a key focus on public health and appropriate water quality criteria for reuse applications, this is the first standard of its type for comprehensive evaluation of water reuse technologies, spanning residential and commercial applications.  Learn more about this standard at: NSF/ANSI Standard 350 - Onsite Residential and Commercial Water Reuse Treatment Systems

Health and Safety Codes

In the first case, code officials frequently oppose such systems because of very legitimate concerns over microorganisms, other biological matter, oils, detergents, salts, and pathogens in the graywater. In many locations, the graywater standards limit application of treated graywater to outdoor (landscape).  By such limiting the application of treated graywater to the landscape, such indoor uses as water for toilet and urinal flushing, water for initial stages of clothes washing, and water for indoor and outdoor clean-up are not available. uses.  However, in some jurisdictions, these limitations do not exist and the full capacity of new treatment technologies cannot be applied to indoor uses.

Product and System Costs

Because of the limitations and their patchwork application as noted above, the requirements associated with the installation and use of graywater systems cannot always be accurately assessed by the manufacturers.  The level of treatment required for specific applications (landscape, fixture flushing, clothes washing, etc.) may differ from jurisdiction to jurisdiction.  As such, the technical specifications of a compliant system may also differ from jurisdiction to jurisdiction.  Costs, therefore, are not readily determined.  A uniform application of a single set of health and safety requirements across North America would certainly serve to aid manufacturers, help in the design of universally compliant systems, and likely lead to lower product design and manufacturing costs.

While the costs of graywater treatment systems will likely vary significantly depending upon the application and the underlying technology of the system, it is frequently not cost-effective to install such a system as a retrofit for the purpose of reusing water inside the building. Instead, these systems are more ideally suited to new construction applications.

System Maintenance

The third significant impediment currently facing manufacturers, code enforcement authorities, and building owners is that of maintenance of these complex treatment systems.  For home applications, the question that is always asked is:  “Today’s homeowner does not regularly maintain a relatively simple home system, the storage water heater.  What guarantees that they will maintain an even more complex system, the graywater treatment system?”  For non-residential applications, the need for ongoing maintenance is required as well.

Several answers have surfaced from the water industry and from others engaged in promoting these systems.  These are merely examples of possible approaches to assuring long-term performance; a combination of the following could be implemented by the manufacturers, working with the local authorities concerned with the health and safety issues:

  1. Manufacturers’ guarantees of performance within a certain set of specifications coupled with lifetime service and maintenance provided (or arranged) by that manufacturer.  This is similar to an automobile warranty wherein all service for the first 50,000 or 100,000 miles (80,467.2 km or 160,934 km) is provided free-of-charge.  In the case of a graywater system, the term would be denominated in years equal to the expected physical or economic life of the system.
  2. Independent service contracts with organizations approved by the manufacturer of the system.  Such contracts would be provided as evidence to the local permitting authority having jurisdiction prior to an installation permit being issued for the graywater system.
  3. Annual inspections of individual systems by the local authority(ies), with the provision that non-compliance with the operating specifications could result in a red-tag disconnection of the graywater system from the building system.

The Marketplace

While the current impediments limit the applications of most of the systems now making their way into the North American marketplace, systems are being promoted and, in some cases, being made available for purchase.

NOTE: Because there has been little field investigation of the majority of the systems now offered in the marketplace, the Alliance for Water Efficiency neither endorses nor promotes any of these specific systems.  The purchaser or specifier is encouraged to perform their own feasibility investigation within the context of the applications being considered. 

Several firms have developed and, in some cases, introduced products into the North American marketplace that are designed to "capture" this very available "source" of water. While some have been in the field for years, others are still in various stages of development. The following systems (in alphabetical order) are currently on the "watch list" of water efficiency professionals:

AquaCycle® by PONTOS®

Independent subsidiary of Hansgrohe AG, Schiltach, Germany a subsidiary, in turn, of Masco Corporation

• Recycles graywater from lavatory sink, shower, tub and laundry for use in toilet flushing, clothes washing, cleaning, and on landscape
• Numerous existing installations in small and large residential and institutional applications in Europe
• Company contact (from North America): 011-49-7836-51 19 20

waterPOD by aquaTECTURE(TM)

• aquaTECTURE manufactures, installs, finances, and operates decentralized, modular water recycling systems that are intended for distributed, point-of-need water recycling applications. waterPOD equipment can treat flows ranging from 1,000 gallons per day to 325,000 gallons per day.
• Title-22, San Francisco Article 12C, and NSF-350 compliant
• Company contact: (424) 832-7017

ReWater by ReWater Systems, Inc., Chula Vista CA

• Captures, filters and reuses shower, tub, lavatory sink, and laundry water for landscape irrigation
• Available since 1990; numerous existing installations with proven track record
• Company contact: 619-421-9121