But before we dive right in, let’s get a few things straight. Greywater is used water from your bathroom sinks, tubs, showers and washing machines. While it may contain traces of dirt, grease or household cleaning products, it does not—repeat, does NOT--contain anything from toilets or washing diapers. However, it’s still not safe for human consumption. 

Greywater may look slightly dark (hence the name), but it can be used to irrigate your yard, water household plants, or even be used to flush toilets. Reusing greywater keeps it out of the sewer and septic system, reducing the chance for it to pollute local water bodies.  

With all of the benefits of using greywater to irrigate, how can you collect and reuse it? Luckily, it doesn’t require any fancy (or costly) replumbing of your pipes to get the greywater into your irrigation system. It’s as simple as letting gravity transport the greywater through a filtered hose, allowing it to seep into the soil.  

Large-scale applications can benefit for a more complex system--pumps, filtration and regular maintenance--to treat and reuse large volumes of water to help conserve water in housing developments, manufacturing plants, schools, universities, and public other buildings. 

While greywater can be used for irrigation, it is definitely not for human or pet consumption, and has special conditions to be aware of. Here are the top 5: 

1.  Greywater can’t be stored for more than 24 hours or the impurities start to break down and create odors. 

2. Due to possible pathogens and bacteria in greywater, irrigation systems should be designed so the water can soak into the ground and not be accessible to people or animals. 

3. Greywater must soak into the soil to keep it from becoming a breeding ground for mosquitos. 

4. Pumps that waste precious electricity should be avoided to keep be your system as eco-conscious as possible. 

5. Greywater is OK for irrigating fruit trees and edible plants (where the crop is far from the ground) like corn, tomatoes, or brussel sprouts, but should not be used on crops that will come in contact with the water or be eaten raw, like strawberries, carrots, or lettuce. 

With so many variables in what may be swimming around in greywater, most cities, counties and states have developed a tier system to know which type of greywater can be used where, and how much.   

Tier One — Less than 60 gallons of light greywater from bathroom sinks, showers, tubs, and washing machines can be distributed per day by a simple gravity system. No treatment of greywater is necessary unless it is applied to a public location, like schools, playgrounds, churches, or parks. 

Tier Two — Similar to Tier One, but less than 3,500 gallons of greywater can be stored in tanks or in pumps for less than 24 hours. No treatment is necessary and the greywater can be distributed through pressure pumps. 

Tier Three — Less than 3,500 gallons of greywater can be distributed from utility and kitchen sinks, dishwashers, and any other greywater that has not come into contact with wastewater from a toilet. Treatment is necessary and is distributed through pressure pumps. 

Best of all, the United States Department of Agriculture approves the recycling of greywater as new, clean freshwater sources are becoming scarce.