Gray Water Systems

What is Gray Water?

• Gray water is used water from clothes washer, laundry tub, bath, shower, and bathroom lavatory
• Gray water is not safe; it contains bacteria and other harmful pathogens
• Waste from toilets, urinals, kitchen sinks, and dishwashers is excluded (black water). There is a high risk of contamination from bacteria and viruses
• Gray water is not as clean as tap water but not as dirty as black water

How does a Gray Water Harvesting system work?

Gray water is collected from the appropriate fixtures and a separate plumbing system is required to divide the waste from black water fixtures, which should go to the sanitary sewer. Gray water is stored underground or above groud and should not be stored without treatment for longer than one day. A Storage tank will need to be pumped clean every 3-4 years to prevent contamination to humans and animals. There are various materials of construction available: concrete, steel, fiberglass, plastic, etc. to ensure the tank structurally sound. However, an alternate source of potable water may be necessary to supplement gray water during certain times of decreased supply. Backflow protection is necessary.

Why Grey Water Systems?

• Water is a valuable commodity
• To provide an alternate supply of water to meet growing demands
• Population growth furthers the demand on municipal supply
• Utility savings
• Possible tax credits and government subsidies.
• Reduces the demand on public water supply
• Decreased wastewater flow to municipal treatment plants

Gray Treatment Options

(depends on quality of incoming water)
ALWAYS CHECK LOCAL CODES

• Filters
• Settling
• Chlorination
• Aeration
• Ultraviolet treatment
• Reverse osmosis
• Ozone treatment
• Water coloring