Wisy Vortex Filter — Pre-Filter for Rain Harvesting Systems up to 5,500 sq ft
Fixed shipping to addresses in the contiguous US!
Features
This is one of our favorite pre-filters — used to filter water immediately after it comes off the roof but before it enters the cistern. This filter works in ALL climates, is winter-proof, and is ideal for applications collecting from more than 4 downspouts on a roof under 5,500 square feet. With the vortex dynamic, the Wisy filter automatically diverts the first flush of water away from the cistern, then routes the remaining water into the tank through a vertically-mounted, stainless steel, cleanable filter screen. The screen also aerates the water as it passes through.
This filter can be installed in both above-ground and below-ground applications. For above-ground installations, a mounting bracket is needed — you can build one from treated lumber, or purchase our stainless steel mounting bracket.
When installing underground, seal all joints (including the swivel joint) with the included sealant tape.
Ease of installation: 8/10 underground, 5/10 above-ground. The varying pipe elevations and potential for settling after installation make this a product best left to someone with experience running drainage piping.
Is this right for you? If you have more than four downspouts and your property has some slope (it doesn’t work well on flat properties unless installed above-ground), this filter is a great choice. Note that the filter is not 100% efficient — expect roughly 70% of water to enter the cistern, with 30% carrying dirt and debris out through the bottom “trash” outlet. If that doesn’t fit your situation, consider our Monjolin filter.
Maintenance frequency: Somewhat often — but it’s not difficult. Pull the screen out and run it through the dishwasher. Occasionally scrub it with dish soap and a soft-bristle brush. Start with monthly cleaning and adjust based on your first year of use. High-tree/high-pollen areas will need more frequent cleaning; low-tree areas may only need it every 6 months.
What else will I need? If installing in-ground, consider adding the 20" riser — keep 4–6" above grade to prevent groundwater from entering the filter. Seal the riser with silicone caulking or the included seal tape. You’ll also need a short piece (~48") of 6" SDR-35 pipe for the inlet bell and gasket. For the middle and bottom fittings, add our 4" and 6" no-hub couplings to adapt to your outgoing pipe.
Tools needed: A level, a shovel, silicone caulking, dish soap (to lubricate the pipe before inserting into the bell and gasket inlet), and something to compact the ground under the Wisy. Oh, and some good ol’ fashioned hard work and determination doesn’t hurt either.
*For potable systems, additional filtration is required. This filter alone will not make rainwater potable.
Principles of Operation
The WISY WFF 150 Vortex Filter separates debris larger than 280 microns from collected rainwater and directs filtered water to the storage tank throughout an entire rain event — eliminating the need for any additional first-flush devices. Its diamond-cut vertical design provides highly oxygenated water to the storage tank.
The WISY WFF 150 is the only commercial vertical filter of its kind in the world. Because of the vertical design, the filter has a self-cleaning effect — debris is discharged along with first-flush water out through the bottom. There is no basket to clean and no sprayers needed to rinse the screen. The filter works on capillary action to deliver the highest quality stored rainwater with minimal maintenance.
Wisy Vortex Filter — installation walkthrough
Wisy Vortex Filter — additional installation guidance
Cistern installation overview featuring the Wisy Vortex Filter
Wisy Vortex Filter — above-ground installation
Documents
WFF 150 Product Spec Sheet · WFF 150 Manual
Visit our Design Library for free plans of commonly requested rainwater collection systems, with itemized component price lists linked next to each design.
