The elephant in the room when it comes to reverse osmosis (RO) is wastewater. It’s no secret that during the filtration process, a reverse osmosis system will expel water at a ratio of 3:1. This means for every gallon of RO water produced, 3 gallons of wastewater goes down the drain. It seems like a lot right? So now the question is, “can reverse osmosis wastewater be recycled?”
The answer is yes! Here’s how; simply redirect your drain line to a container that could collect the wastewater such as a bucket, or 5-gallon water bottle (depending on how much water is used, a larger container might be needed. Use your RO system as you normally would and occasionally check in on the wastewater vessel. Once it’s filled, replace the vessel with another and use the collected water for various things around the home.
Another method in collecting wastewater is to route the drain line coming from the membrane to go outside. Run the drain line from the kitchen to a collection area outside or drill a small hole through the wall under the kitchen sink and feed it to a rain barrel outside.
Once the wastewater is in the vessel, it can now be used to water plants in a garden, wash a car, used for cleaning, wash dishes, refill a decorative fountain, laundry, flush toilets, and make cement. The wastewater may look clean, but keep in mind that it is filled with impurities that the RO membrane rejected. It is not advisable to drink or bathe with wastewater.
Here’s a tip, if you’re going to be using a rain barrel; place the barrel at least 1 foot off the ground. This added clearance will allow you to install a brass ¾” spigot. That way you will have a gravity-fed water source to attach a garden hose to. This will make it easier to use the collected water for the things mentioned above. Another tip is to attach a drip irrigation garden hose to the rain barrel. The slow-release of water allows the soil to gradually absorb the water and keep plants healthy.
Recycling RO wastewater is a great way to mitigate the impact of waste that occurs with a reverse osmosis system. Any household that uses an RO system can utilize all of the water going through the filters and membrane in various parts of their home.