Grey Water Recycling Systems for Homes

What is Grey Water? 

Some consider the kitchen sink to be grey water, while others view it as black water because of the high organic potential, so keep that in mind. Grey water is the water that goes down the drain from a laundry machine, bathroom sinks, shower, tub, and dishwasher. Grey water may have soaps and some minor amounts of biologicals, but nothing serious. Grey water is not clean drinking water, and it is not blackwater, which is anything that has feces or sewage in it.

Is Grey Water Recycling New?

Perhaps the first example of grey water is in the ancient city of Eshnunna, 50 miles north of Baghdad. This city contains brick sewers connected to water-flushed latrines, embodying modern sewage treatment's essential principles — in 2500 BC.

There is a long history of recycling grey water in residential homes. Our ancestors were sustainable long before it was even a word. Grey water was used for everything in the house except drinking and cooking. Many historic rural farmhouses still in use today have or had grey water systems installed. The most common grey water systems separated the grey water from the sewage to reduce the septic system's strain. Grey water recycling systems were built by piping the laundry and tub drains outside, where people used them for plant irrigation and groundwater recharging. Other heritage systems used grey water for flushing toilets and laundry.

Are Grey Water Recycling Systems Allowed?

As long as you follow the proper plumbing code within your jurisdiction, there should be no issues with grey water use within your home. There are policies already in place in numerous states, and it is in the Plumbing Codes in the US and Canada. Before allowing it in your home, inspectors will want to ensure that clean, potable water lines and grey water lines are clearly marked and separated. Different colored supply lines that are appropriately labeled are essential to creating a safe grey water reuse system. Finally, a conversation with your public health and building officials is critical to success.

Are Grey Water Recycling Systems Safe?

The critical detail is making sure that family members and future owners are not drinking grey water in your home. Most of your family members will not drink from the toilet or laundry tub except for your dog. This is where you would most commonly be reusing grey water, so your health is not at risk with a system like this. There are some fantastic and confirming data on the lack of health issues of grey water reuse systems here.

How Does a Grey Water Recycling System Work?

If you are using it for irrigation, drain lines from your grey water sources are plumbed together and run outside, under the soil where they drain into the yard for irrigation. The drain lines cannot be done haphazardly, as the pressure from your laundry tub draining can be pretty damaging to landscaping and root structures. Drip lines, proper layout of drain lines, and types of garden features can help manage the pressure of water to trickle out into your yard.