Five Ways to Filter Your Rainwater Harvest
Capturing rainwater as part of even a small off-grid water system is a great way to cut utility costs and extend your water supply during times of drought. Since we typically capture rain as it flows from our roofs, it’s important to set up some sort of filtration process to ensure roof particulates and debris don’t get into the water supply. Roofs can collect everything from animal debris to leaves and twigs — and since most roofs are made from asphalt, shingle debris can drain right into your rainwater supply tank.
If you’re planning on bathing or drinking the water, filtration is a necessity to keep you safe. This article covers five ways to filter your rainwater harvest to make it clean enough to drink.
Rain Brothers installs both underground and above-ground cistern units designed to capture your rainwater harvest. Over the years, we’ve identified the best methods for the rainwater filtration process. We install these systems and also sell them as stand-alone pieces in our Rain Brothers catalog.
Five Key Rainwater Filtration Methods
1. Pre-Tank Filtering
You can and should filter the water before it hits your cistern tank, if possible. We use the Wisy Vortex pre-tank filter for all of our installations designed to provide drinking water. The Vortex is a filtration hub where multiple downspouts run water inside it, and it meets Ohio Health Department requirements for roof washer filters.
2. In-Tank Filtering
You can use the cistern design itself to help filter debris in the tank. The pipes going into the tank can be designed as a “calming inlet,” where incoming rainwater is taken all the way to the bottom of the tank. This reduces turbidity — cloudiness from suspended debris — and helps keep the water oxygenated and cleaner. You can also use a floating intake filter to pull water from the cleanest part of the tank, which is not the bottom where sediment naturally settles.
3. Carbon Filtration
Carbon filtration is an important step toward cleaning water for drinking — it also helps the rainwater taste better. Activated carbon filters do a nice job removing harmful water contaminants before the water is disinfected. These filters trap pollutants right in the carbon, making for an effective rainwater harvesting filtration method.
4. Sediment Filtration
Any remaining sediment should go through one final filtering process before sterilization. In Ohio, particulates should be reduced to about five microns — small enough to filter out cysts that can make you sick. Rain Brothers typically adds a sediment filter just before the sterilization stage.
5. UV Sterilization
Even after all these filtration steps, the final and most important part of cleaning your rainwater harvest is sterilization. We typically use a UV filter to remove waterborne microbes and bacteria that could make you sick. UV sterilization is a more natural process than adding chlorine, and one we highly recommend.
Rain Brothers is standing by to help you establish and maintain your own rainwater harvest. Call or text us at (937) 949-1100.
