Friday, February 28, 2014

Pros and Cons of Using Gray Water Part I

Map of California and record precipitation for the 2013 and 2014 year. 

I am sure we have all seen these signs on the side of the road indicating that the highway landscaping is being watered by grey water. There are many city and county sites where grey water is being used to water the landscape. 

California is experiencing its longest and hottest drought in centuries. While the rest of the nation is dealing with arctic winter (2014), California's beautiful weather hides a sinister side. No rain! The low precipitation and little rain has rekindled the infamous Water Wars in California. The environmentalist want water for the rivers and lakes to protect the wildlife. The farmers want water to irrigate their fields and grow food for the nation. Homeowners need a water too. Did I leave anyone out? 

As of this posting the Federal Government has declared that the farmers in the Central Valley (of California) will not be receiving any federal water. Read about it here. 

While the politicians argue over water and where to get it from many homeowners are looking towards their own alternatives. Recently, Viking Dad and I have had discussions with other other small Homestead owners about the use of graywater. As I kid I knew my Grandfather used the graywater from my Grandmother's washing machine to water the lawn and the orchard. I  knew the lump in the lawn was the holding tank and that was the extent of my knowledge. He was pretty "far out" in his thinking when he built my Mom's childhood home in the 1940's. However, being a "Californiaos" he knew the importance of water conservation even then. 

Lets first define Greywater.

Greywater gets its name from its cloudy appearance and from its status as being between fresh, potable water and sewage water ("black water"). In a household context, greywater is the leftover water from baths, showers, hand basins and washing machines only. 

Graywater is different from warm-up water (wasted tap water that is allowed to run down the drain before it reaches a desired temperature). Warm-up water that has not been used for bathing or dishwashing is generally free from bacteria and other pathogens. The amount of wasted warm-up water can be significant in homes where water heaters are located a considerable distance from showers or tubs and where no recirculation system is installed. Catching this water in a bucket and using it to water plants can contribute to home water conservation savings.

Some definitions of greywater include water from the kitchen sink. Any water containing human fecal waste is considered black water.

There is some discussion regarding the use of water from the kitchen sink. It is believed to be a cautionary area because of the possible bacteria and pathogen contamination that can occur from various food items going down the sink and into the holding basins. In California it is required to filter the water coming from the kitchen sink. 

What are the Pros and Cons of using Graywater?


  • Lower fresh water extraction from rivers and aquifers
  • Less impact from septic tank and treatment plant infrastructure
  • Topsoil nutrification
  • Reduced energy use and chemical pollution from treatment
  • Groundwater recharge
  • Increased plant growth
  • Reclamation of nutrients
  • Greater quality of surface and ground water when preserved by the natural purification in the top layers of soil than generated water treatment processes.
  • Reduce in cost.
  • Conservation of water use
  • During a drought can be an less expensive alternative to city/county/federal water sources. It also relieves the pressure off the ecosystem during a drought. 


  • If graywater is mishandled can spread diseases or contaminate in which can be spread and make the water unusable.
  • If grey is not filtered correctly then it can become extremely smelly. Unfiltered graywater must be used within 24 hours. 
  • Depending the water quality and source water quality could damage soil quality; ie too much salt.
  • not enough water in the city/county sewer system to push sewer through the system. 
  • Graywater may contain fats, oils, grease, hair, lint, soaps, cleansers, fabric softeners, and other harmful chemicals
  • Even biodegradable soaps and detergents can present a problem over a period of time when grey water is used for irrigation.
  • Most cleaning agents contain sodium salts which can create an alkaline condition and damage the soil structure
  • Soil type. Certain soils are better at accepting graywater then others. Clay, for example, is unsuitable because it is impermeable. 
  • Cost prohibitive. In some areas the permit process or equipment requirement could become cost prohibitive. Always check with your city/county/state to determine if graywater use is acceptable. 

Before establishing or creating a graywater system check your soil condition, acceptability in your city/county or state and precipitation levels. Look for local water sustainability or graywater organization to learn how to properly set up a domestic system. 

Bless Bless.....

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