One of the many ways commercial facilities are reducing their water consumption is to re-use the “gently used” water — called grey water — that comes from restroom sinks, kitchen sinks, and showers. These facilities are often “doubled plumbed,” with grey water going into storage tanks, and water from toilets and urinals discharged into sewer systems.
While some grey water may look discolored, even “dirty,” and is not safe for human consumption, it is usually safe, even beneficial to use it to irrigate vegetation. Facilities that are landscaped often use more water for vegetation than anywhere else, so if water can be re-used here, it can prove to be a significant water and cost savings.
However, according to Klaus Reichardt, CEO, and founder of Waterless Co. Inc., manufacturers of no-water urinals, there are some rules and guidelines for using this kind of water properly.
- Grey water should not be stored for more than 24 hours. After that, it will start to breakdown and odors may develop.
- Avoid touching grey water. While it is “gently used” water, it can contain pathogens that are harmful if consumed by people.
- Don’t let water “pool” on the surface. This can result in mosquito breeding grounds.
- While some plumbing will be required, as mentioned earlier, elaborate pumps and filters are usually not necessary. These extra systems require maintenance, can be costly, and need energy to operate.
- Don’t over water vegetation. Irrigate vegetation with the same amount of water as you would with freshwater.
- Install a valve system that makes it easy to switch from a grey water source to a freshwater source, just in case the tank is dry.
“Building owners and managers should also switch to grey water friendly products,” says Reichardt. “For instance, many environmentally preferable cleaning solutions, laundry detergents, even dishwashing detergents will not affect the pH of water so they can be perfect for grey water.”