Yes, you should always filter rainwater before it enters your storage tank.
Filtering rainwater is a crucial step in any rainwater harvesting system, regardless of how you plan to use the collected water. According to experts, including the guidance provided in the reference, the water you collect should be filtered before it enters your tank.
Why Filtering Rainwater is Essential
Filtering rainwater before it reaches your tank helps remove physical debris, such as leaves, twigs, insects, and sediment, which can accumulate on your roof and in your gutters. This pre-tank filtration is vital for several reasons:
- Protects Water Quality: It prevents contaminants from entering the tank, which helps maintain the quality of the stored water.
- Preserves Tank Lifespan: Sediment and organic matter can build up in the tank over time, reducing its capacity and potentially causing issues.
- Protects Pumps and Appliances: If you use a pump to distribute the water or connect it to household systems, filtering protects pumps, pipes, and appliances from clogging or damage caused by debris.
The need for filtration applies to all uses as mentioned in the reference:
- Watering the garden
- Washing the car
- Connecting your water tank to your home (for potable or non-potable uses)
Essential Pre-Tank Filtration Steps
Effective rainwater harvesting systems incorporate filters before the water enters the tank. These typically involve multiple stages to capture different sizes of debris.
Common pre-tank filtration methods include:
- Gutter Guards/Screens: Prevents large leaves and debris from entering the downpipes.
- Leaf Eaters/Screens on Downpipes: Filters out smaller leaves, moss, and insects before the water travels further.
- First Flush Diverters: Redirects the initial flow of rainwater (which can contain accumulated dirt, dust, and pollutants from the roof surface) away from the tank.
Here's a simple breakdown of common pre-tank filtration stages:
| Filtration Stage | Purpose | Debris Removed |
|---|---|---|
| Gutter/Roof Screen | Stops large debris at the source | Leaves, sticks, large insects |
| Downpipe Filter | Filters water entering the downpipe | Smaller leaves, moss, insects |
| First Flush Diverter | Diverts initial contaminated water | Dust, pollen, roof residue, fine silt |
Implementing these filtration steps ensures that the water entering your storage tank is cleaner, safer, and extends the life of your rainwater harvesting system.
