Greywater and/or Dual Plumbing System Purchase Tips

There are three levels of greywater system currently available. The table below (courtesy of Home Energy Magazine) briefly describes the features and cost (in 1995) of these systems.

Types of Greywater Systems Currently Available

System Type Source of Graywater Features Cost
Low – tech owner or professional installation Washing machine only 200 micron mesh filter

55 gal garbage can w/locking lid

$400 – $800
Medium-tech Uses all graywater sources Sump pump to pvc tubing

Subsurface drip irrigation

200-micron mesh filter

(2) 55 gal. storage tanks

$1,000 – $1,500
Fully automated Professional installation Uses all graywater sources Automatically back-washed sand filter

250 gallon storage tanks

Pumps at both source and tank/filter

3-way valve, backflow preventers

Microprocessor controls all flows

Backed by potable water

$2,500 – $5,000

Source: Bennett, Dick. 1995. “Graywater An Option For Household Water Reuse“, Home Energy Magazine. July/August 1995.

Buyer beware is the message according to Oasis Design. These experts feel many claims by greywater manufacturers are overstated. Homeowners should consider the following points before purchasing a greywater system:

  • Most new greywater reuse systems are abandoned or achieve less than 10% reuse efficiency within five years.
  • Many greywater systems consume so much energy and materials to save a little water that the Earth would be better off if the water were just wasted instead.
  • The economic pay back time for the majority of complex (as opposed to simple) greywater systems is often longer than the system life.
  • The majority of “successful” greywater systems are so simple as to be beneath recognition by regulators, manufacturers, consultants, and salespeople (e.g. a garden hose hooked up to the bathtub drain).
  • Claims made for packaged systems are often greatly inflated. Some are very expensive and many don’t work.
  • A web search on any variant of “greywater” will yield hundreds of sites, most of which could be used to illustrate the errors above. Many of these errors are recognizable from manuals of the early 70’s, reprinted verbatim on the web as cutting edge, despite having been discredited in the field for twenty years.

The bottom line is: research any system carefully before taking the leap into greywater.

Greywater and/or Dual Plumbing System Incentives or Rebates

Some water providers and/or cities may offer financial incentives for installing a greywater recycling system. Such incentive programs are uncommon so check with your water utility for information on programs in your area. It is more likely that there are specific regulatory barriers to creating a greywater system in your area.

In many cities and states there are specific regulations against reusing greywater. These regulations are usually in place because of water rights and health department regulations. The water rights issue has to do with consumptive use. Greywater systems put some water to consumptive use instead of sending down a sewer to a wastewater treatment plant and ultimately back into waterways where downstream water rights holders can access it.

In some states the department of public health regulates greywater systems in the same manner as on-site blackwater systems. These regulations would require greywater to be treated in a septic tank just like blackwater and then sent to a conventional leaching field. Treated greywater can only be used for irrigation if the effluent meets standards for biochemical oxygen demand.

It is important that you understand the regulations controlling greywater in your area before embarking on any greywater project.

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