Tuesday, December 17, 2013

Grey Water vs Black Water Part 1

Over the course of my next few posts I will be explaining my plan for my grey water system (also spelled gray water), its limitations, and its benefits. If you have been interested in or are considering a grey water system, you may find my research helpful. Please feel free to ask questions and add to the discussion in the comments below. I welcome any feedback you may have.

I have been designing the plumbing system for my new home to be efficient and green. There are several factors that will play into how one designs and executes the plumbing in a shouse, such as: A) where kitchen and bath are located, B) sewer or septic, C) codes, and D) pipe or Pex. You would be surprised how complicated it can be to design your own system. A couple of these factors were already decided for me. First, my property already has a septic tank installed and, secondly,  I am installing a composting toilet as opposed to a flushing one.

One thing that has always been a non-negotiable for me in designing my plumbing is my desire to install and use a grey water system. Grey water is generally water that comes from bathing, washing dishes, and laundry, that is used to water the yard. It does NOT include water from the toilet. Some areas do not allow for grey water use (check with city and county codes where you live) because they simply don't trust people to use the system safely. It is more complicated than just running a drain line out into the flower bed, which is what many people think is how a grey water system functions.

The most basic of grey water systems is using a basin to wash dishes and then walking the water out to the garden to water plants. While this is an excellent way to reuse dish water, there are factors that must be considered or what you pour into your garden may just kill your plants. Draining washing machine water from a load that was used to wash diapers is also considered bad news. Feces is the enemy of the grey water system. Your job in designing your grey water system is to ensure that feces doesn't make it to the garden and that bacteria and germs are not encouraged to fester.

When I began researching this idea I found that lots of information is out there, but much of it is impractical and/or outdated. After sifting through all the detritus found on the net, I have narrowed my system down to this:

  • Water from the kitchen sink, bathtub/shower, bathroom sink, and washing machine will all be routed to grey water pump, which will then pump the grey water to a mulch bed away from the Shouse. 
  • The mulch bed will be built using trenches to run the pipe, Y's to branch the pipe out, and then the pipes will dead end in specific mulch beds. 
  • The mulch beds will be next to trees and garden beds to assist in irrigating them. I will NOT be watering root based vegetables with grey water. 
  • A diverter will allow me to run the drain water into the septic if there is any chemical (bleach for example) or feces potential (washing diapers or a poopy kid) in the water. 

While this is a very simplified overview of my grey water system, I will be going into detail about it in the next few posts. There are some definite considerations when considering a grey water system, but the most important is SAFETY. Not breeding bacteria, germs, mosquitoes, or creating a drowning hazard must be built into whatever system you settle on using. Also, you must consider how much water your household uses on a daily basis. Too much water can be as bad as too little. The size of your system must be proportionate to your water usage. My next post will begin with what kinds of cleaning products can safely be used in a grey water system and which ones should be diverted to a sewer or septic system.

Do you use a grey water system or recycle your water in some way?