We Live in Fear

Regarding #6, reusing greywater in toilets; For most houses, reusing the greywater in toilets is not economical, or the most beneficial re-use of the water (onsite treatment is a viable option for residential building complexes) If the lot has garden space, the most beneficial method is reusing the graywater every day in the garden. If there are 4 people in the house, about 100 gallons per day would be re-used, resulting in 150 gallons of potable water NOT being used per day on the garden (using greywater daily is far more efficient than using potable water twice per week - this is why 100 gallons of greywater will save 150 gallons of potable). This would save about 40,000 gallons per year of potable water, compared to saving about 12,000 gallons per year reusing greywater in the toilet in the same household, with the toilet system costing twice as much as the garden irrigation system. These water savings do not apply if doing the laundry to landscape method, nor the branched drain system. Both of these methods are very inefficient as the greywater is not distributed evenly or over a wide area, with most of it going into the subsoil, away from the root zone. If interested in the science behind all of this, go to http://www.besthomewatersavers.com/pages/Graywate… Even purple pipe (county supplied reclaimed water) is not that efficient - it takes 8 times as much power to treat the water offsite and bring it back, than to simply allow the graywater to be handled on site. In San Diego there is not enough rainfall to justify an engineered rainwater harvesting system for a typical lot. With only a three month wet period, huge tanks / cisterns would be required to maintain storage over the dry months. Feel free to email me - paul (at) justwatersaversusa (dot) com
— July 28, 2010 6:07 p.m.