Everyone living in a rural area should have a working greywater system. Most do not, and many others do not even know what it is. For the record, greywater is all household waste water except sewage/toilet water (better known as black water). It includes water from laundry, dishes and the bath. Because of dangerous fecal contamination, it would not include diaper rinse, or water used in cleaning animal stables, or bath water from someone with a communicable disease. But the line is a fine one. Greywater will usually contain some level of black materials like dead skin, food particles hair saliva, grease, detergents, crap residue , bacteria and chemicals. The question is how much is too much?

Because of the possible dangers, most municipalities do not distinguish between black and grey water. All household wastewater is considered black and must be disposed of in a sewer pipe, septic field or collecting depot. In areas with septic fields only, this puts a tremendous strain on the system. Our wastewater authorities are encouraging the use of septic fields to dispose of greywater, but owners should realize that the life of their field can be greatly prolonged by reducing water input. As an alternative, a simple system can be set up for home use cheaply and easily. Here area few suggestions. 

  • Greywater systems do not work well in crowded areas. If you have only a quarter acre and are surrounded by other homes some other alternative may have to be found. 
  • Greywater is best absorbed and neutralized by living plants. Soil organisms break down organic materials into water soluble plant nutrients. Plant roots take up these nutrients and much of the water as well. The pure water left over seeps down to replenish the aquifer.   As a sensible precaution do not use greywater directly on anything you will eat later like radishes, carrots, potatoes and lettuce. Instead place your outflow in orchards, pasture, and on ornamentals. Lawn watering is acceptable but beware of possible contamination for animals and children. If you prefer a self regulating system, site your outflow on a well drained part of your property well away from streams and neighbors. Dig out a 6’X6” hole and fill with sand to filter and increase absorption. 
  • Filter and strain all greywater to remove the larger particles of food, grease, etc.—compost or feed this to your chickens. Set up a steel drum or wooden box with different layers of materials for additional filtering (see diagram my book pg. 20). Sawdust or woodchips is best for your first layer. Direct the outflow into your leach field—an upside down flower pot with the pipe stuck in the top makes for splash free dispersal.   Dilute with 50% freshwater for best results although this is not always necessary. On well drained sandy soil figure about a half gallon of greywater per week for every square foot of soil—less for hardpan. Keep an eye on things to see how the plants respond.
  • Your ideal system might include a pit lined with plastic and filled with topsoil. Greywater would feed the trees and ornamentals in the pit without leakage into surrounding soil. If you want to get fancy bury some perforated plastic pipe to disperse the filtered water like a septic field. (see my diagrams pg 22 &23) 
  • Keep greywater in pipes or underground as much as possible. Do not spray on plants or hard surfaces as this defuses the water into microscopic droplets, which could spread contaminants. Do not store for more that a day or two or allow to puddle. A thick mulch of hay, wood chips or even cardboard speeds decomposition and provides protection for youngsters and pets.
  • Avoid bleach, fabric softeners, boron, phosphates, ammonia, chemical cleaners, and hot water, as these will damage plants.