Rainwater Filters

Intewa USA – Purain Rainwater Prefilters

Introducing Intewa, manufacturer of the Purain hydraulic jump rainwater filter. This hydraulic jump technology is a vast improvement over the vortex filter design. It cleans itself automatically during a heavy storm. The design inspiration comes from nature: you see it in streams. As water flows over large rocks, a swirling eddy forms at the base.  The stones are washed clean by the hydraulic force.

During lighter rainfall, the filter is 100% efficient. This is very different from cascading and vortex filter designs, where the first (only?) rain washes away.

The 4" and 6" sizes are molded plastic, and the larger sizes are fabricated from plastic sheets. Georgia Water Tanks stocks Intewa Purain rainwater filters from 4" to 16" at its warehouse in Atlanta, GA.

See the chart below for sizes and recommended flow rates:

SDR 35 Pipe SizeMax. Flow RateRooftop Area (Atlanta)Above-Ground ModelInlet Centerline
to Filter Top
Below-Ground ModelInvert*
4"0 - 90 gpm1500 s.f.PR1003"
6"60 - 270 gpm5000 s.f.PR150S4.1"HD1505.9"
8"270 - 576 gpm10,000 s.f.PR2005.4"HD2006.1"
12"577 - 1684 gpm30,000 s.f.PR3008.75"HD30010.7"
16"1685 - 3630 gpm70,000 s.f.PR40010.2"HD40013.62"

* The "Invert" in the chart above is the drop from inlet to outlet. These are some of the lowest in the industry, much lower than conventional vortex filters, and allow for filters to be installed inside tanks, out of sight.

The below ground models are suitable for direct burial, and have an access opening for filter cleaning. 


Rainharvesting Pty. Leafeater Advanced

There are more expensive downspout filters, but our experience is that this one is the best. . . 


The Leaf Eater Advanced™ is the next generation Rain Head, featuring the new Clean Shield™ (single screen) technology and VH Pivot™ outlet. The Leaf Eater Advanced™ Rain Head prevents debris from entering the Rain Harvesting system, improves water quality and reduces tank/cistern maintenance.

The single screen incorporates Clean Shield™ technology which deflects leaves and debris away from the flow of water. This minimizes maintenance and enhances catchment efficiency. This Rain Head incorporates a VH Pivot™ outlet that swivels to suit vertical or horizontal downspouts. The Leaf Eater Advanced™ can also be used as a debris removing device even when rainwater is not being collected.

Features and Benefits

  • Compact, versatile rain head for quick and easy installation
  • Single screen technology for advanced debris shedding (Clean Shield™)
  • Minimal maintenance
  • Pivot the outlet to suit vertical or horizontal (rear outlet) downspouts  (VH Pivot™)
  • High flow rate performance
  • Superior catchment efficiency at low and high flow rates
  • Single screen with 1/32″ aperture mosquito proof stainless steel mesh
  • Include adaptor for secure connection to downspout
  • Available in 3" and 4" Schedule 40, and 2x3 / 3x4 rectangular.

Residential Water Quality Device

Rainharvesting Pty. Filter Pit


Filter Pits handle large volumes of rainwater and enable screening to be done at a central point in the system. In some cases they can be safer and easier to clean than rain heads fitted at roof gutters.

Filter Pits are extremely beneficial when used in conjunction with underground tanks/cisterns or where tanks/cisterns are placed downhill from the building. They are usually placed at a convenient spot in the garden, between the tank and the house. Filter Pits are a ‘junction’ where the various pipes from around the house meet from which the main pipe or pipes then connect to the rainwater tank/cisterns.

Features and Benefits

  • Prevents leaves & debris from entering infltration area
  • Suits a variety of outlets to the tank – pipes can be 3.5″ up to 6.6″ outside diameter and can be in multiples to take the flow
  • Available in 22″ and 27.6″ sizes. The size will depend on the number of pipes entering the pit
  • Includes a stainless steel mosquito proof screen (1/32″ aperture) and lid
  • Optional junk basket for larger debris removal which incorporates a 1/4″ aperture stainless steel screen
  • Optional height extensions are available to increase the height of the top of the filter pit to ground level


3731 Northcrest Rd, Suite 28, Atlanta GA 30340             404-991-0404          rdhanson@georgiawatertanks.com​

Contact Us


Purain USA

Product information, video demonstrations, etc., here


Purerain Video Demonstration