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Gray water

GRAY WATER reuse is a much debated topic in the public health sector today. Generally the public is interested in reusing water and many homes are currently being fitted with gray water recycle storage tanks. Much of this is being done by individual homeowners without jurisdictional approval. They want to collect laundry water, bath water, rain water, etc. The problem is unanticipated contamination which can render the storage tank a health hazard and a festering, stinking mess.

Gray water

The reuse of household gray water can be dangerous if improperly collected or cross contaminated, which is exactly why Public Health Officials are having a tough time dealing with what seems to be such a good idea to the general public.

Our advice at Darco:

  • Always talk with your City or County Dept. of Public Health before moving ahead
  • Do your homework to understand the concept and possible sanitation problems
  • Isolate black water (sewage) into a separate dedicated piping system
  • Install a selector valve routing gray water either to storage or wastewater / sewer / septic tank
  • Install a check valve to prevent sewage backflow into the gray water system
  • Avoid contamination from food scraps, human waste, and body fluids
  • Don't store gray water for extended periods of time
  • Use gray water only for outside irrigation rather than household tasks
  • Wear rubber gloves while watering with a hose and avoid skin contact
  • Dilute collected household gray water with rain water if available
  • Chlorinate the tank when full to 10 ppm for 24 hours, at least once a year
  • Remember, if the stored water starts to smell septic, it isn't gray water anymore

A few typical "common sense" guidelines:

  • Be sure your family knows and follows the household "Gray Water Rules"
  • The safest gray water sources are the laundry machine and bath tubs
  • Soap generally improves the water quality in any gray water storage system
  • When you have house guests who may not understand or follow the rules, turn your selector valve to "sewer position" to bypass potential contamination
  • Use caution collecting water from the kitchen sink or dishwasher as food scraps and grease may decompose over time and contaminate the system
  • Urination in the shower must be strictly forbidden (common with young boys)
  • Laundry water from clothing badly soiled with excrement, blood, or vomit should be bypassed to the sewer system
  • Do not spit into hand sinks if plumbed into the gray water system
  • Avoid water from bathing a dog, flushing an aquarium, or cleaning a pet's cage
  • The addition of rainwater helps dilute and "sweeten" household gray water
  • If you think your stored water is getting a little sour: chlorinate it with liquid laundry bleach to 10 ppm, let it stand for several days while the chlorine dissipates, pump it out where any residual chlorine will not damage trees or plantings, attempt to figure out what went wrong, and then try again

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Bennett, CO 80102 || (800) 232-8660
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