What Do I Need to Know About Recycling Sewage for a Vegetable Garden?

Gray Water vs. Black Water

• Gray water has been used for nonhazardous tasks such as bathing and dish washing. Water that has been used for flushing toilets is classified as black water. Gray water is reasonably safe to use for other purposes after only mild treatment or, in some cases, none at all. Black water should never be recycled without being sent through a wastewater recycling facility.

Gray Water and Gardening

• Recycled water can be used to irrigate and water your vegetable garden. The best reclaimed water to use is water that has been treated by a wastewater recycling program. If you do not have this option, you can use gray water that was originally used in your bathroom sinks, showers or bathtubs. Gray water intended for gardening use should be used immediately and not stored for any length of time.

Potential Hazards

• The best type of gray water to use for gardening is water that was not exposed to a significant amount of chemicals or potentially harmful wastes. This is why water from a kitchen sink or the dishwasher is not normally repurposed for gardening. If you are planning on using gray water for your vegetable garden, you want to make sure you are not adding anything toxic to the water when you use it the first time. This means reading the labels on your soaps and beauty products to make sure you are not contaminating your bath or hand-washing water that you plan on using in the garden. Contaminated water can harm your plants and soil and even lead to health problems for you and your family.

Accessing Recycled Water

• If you live in a community that has a wastewater recycling program, you can contact your wastewater management facility and learn about the program, including how to access recycled water for your gardening and agricultural use. If you are unsure whether your community has such a program, your local water treatment facility will be able to tell you. If you do not have municipal water, your access to treated recycled water will be limited, though you can install systems to help recycle your sewage water into a useful substance. These systems tend to be fairly costly and will probably counteract any financial benefit you would get from using recycled water instead of fresh. Some homeowners obtain untreated gray water by modifying the plumbing in their homes to deposit the water that drains from safe sources (showers, sinks) into a cistern or other collection device and then using the water that is collected. Some areas have legal restrictions regarding modifying your plumbing, so check your local laws before attempting this method of gray water collection.