Grey Water Systems

What is greywater?

Any washwater that has been used in the home, except water from toilets, is called grey water. Dish, shower, sink, and laundry water comprises 50-80 percent of residential "waste" water. This may be reused for other purposes, especially for landscape irrigation.

The statistics behind water usage

A family of four in Cyprus has a daily consumption of 100-130 lt per person (annual consumption per person: 100-130m3)
Water consumption in large cities (not Cyprus) is estimated at 300-600 liters per person per day, while in small towns 100-150 liters
Although a person needs 50 liters of water a day to meet their personal and household needs in developed countries, we use up to 500 liters
When a faucet drops drip-drop within a year, it may drain water that would be sufficient to fill at least 35 times a bathtub
A running cistern (tank) can empty in one day water that we will drink in 50 days
When we wash our teeth or hands by leaving the tap constantly open without needing it, we are wasting water that could fill up 10 large bottles
45-75% of the water we use in our homes is used in the bathroom, toilet, and during cleaning
Production of half a pound of meat requires 100 times more water than the production of half a kilo of wheat
It takes 2 liters of water to cook a pan of spaghetti and 4.5 liters to wash the pot

Why is Greywater important?

Viewed narrowly, grey water systems don’t look that important. A low flow shower-head can save water with less effort. A septic system can treat grey water almost as well. But when you look at the entire picture, the keystone importance of greywater is revealed.

“Ecological systems design is about context and integration between systems. The entirety of integrated, ecological design can be reduced to one sentence:

Do what's appropriate for the context.“

Art Ludwig, Oasis Design

What are the benefits of using greywater?

Lower fresh water use (16-40% decrease of potable water use)
Less strain on failing septic tank or treatment plant (decrease on water & wastewater utility bills)
Alternative source of irrigation water
Better treatment (topsoil is many times more effective than subsoil or treatment plant)
Groundwater recharge
Less energy and chemical use - (approx. 2W-hours per gallon of water and chemicals needed to treat wastewater)
Facilitates home grown food production
Connects people to their yards: It increases awareness of and sensitivity to natural cycles
Plant growth: The nutrients in the greywater such as phosphorus and nitrogen provide an excellent food source for plants
Reclamation of otherwise wasted nutrients