Example of Purain self cleaning rainwater filter when there is high rainfall


Hydraulic jump filters with self-cleaning technology for maximum rainwater capture.

Self-cleaning Purain rainwater inlet pre-filters have the highest rainwater capture of clean rainwater with exclusive hydraulic jump technology patented by INTEWA.

Using the unique jump filter design, Purain filters catch 100% of rainfall up to a certain flow rate. At higher flow rates, the filter is vigorously cleaned using what is called a hydraulic jump action. This leads to the highest overall water capture efficiency regardless of geography.

For grey water and storm water management applications, Purain pre-filters guarantee an effective reduction of debris, and provide a cleaner water to process for end use applications.

purain filter low rainfall diagram

PURAIN Product Range

PURAIN filters come in a wide range of sizes from 4” to 16” inlets.


PURAIN 8” to 16”

purain commercial filters rainwater

This PURAIN product line is developed for in-tank installations or wall mounting. The filters are sized for pipe diameters of 8”, 12” and 16” SDR 35 PVC.

Product Article Numbers
  • 8” PURAIN filter DN200/Article number: 210145
  • 12” PURAIN filter DN300/Article number: 210155
  • 16” PURAIN filter DN400/Article number: 210165

Heavy Duty Commercial
Direct Bury Applications

PURAIN HD 8” to 16”

PURAIN heavy duty rainwater filters

The PURAIN HD line is designed for underground installation with a vehicle rating up to 60 tons. These filters are accessible with conventional manhole lids and concrete rings, and they are sized for pipe diameters of 8”, 12” & 16” SDR 35 PVC.

Product Article Numbers
  • 8” PURAIN filter HD DN200/Article number: 210146
  • 12“ PURAIN filter HD DN300/Article number:210156
  • 16” PURAIN filter HD DN400/Article number: 210166

Large Roofs and Grey Water
Recycling Applications

PURAIN 6” and 8”

PURAIN greywater recycling

This PURAIN product line is the most versatile and cost effective. The injection molded filter can be buried, mounted inside the cistern, or mounted externally. For in-tank mounting, they have a skimmer overflow.

Product Article Numbers
  • 6” PURAIN Filter DN150-S with skimmer :210176
  • 6” PURAIN Filter DN150 without skimmer: 210178
  • 6″-8″ PURAIN Filter DN 150-200 with skimmer: 210154
  • 6″-8″ PURAIN Filter DN 150-200 without skimmer: 210153

Small Roofs and Greywater
Recycling Applications


PURAIN greywater recycling

Ideal for small single-family house, the PURAIN (4”) includes a non-return valve, small animal protection, and skimmer overflow. It is also available without the non-return valve.

Product Article Numbers
  • PURAIN filter DN100 with skimmer, without non-return valve/Article: 210136
  • PURAIN filter DN100 with skimmer and non-return valve /Article: 210135

PURAIN Accessories

  • Purain Cover
    for PR100 and PR100-M
    Recommended for filter installation outside the tank.
    Article Number: 210152
  • Cover for PR 150-C
    Used when ground or wall mounting the PR 150-S and PR-150-200-S. For mounting in-tank, in- ground, or on a wall.
    Article Number: 210148
  • Backflushing Nozzle
    for PR100 and PF300-100-C
    Where filters are installed in hard to reach tanks, we recommend using the backflushing nozzle set PR-100-RSDS.
    Article Number: 210138
  • Stainless Steel Pipe
    Connector DN100
    Stainless steel construction watertight, detachable joint connection for DN100 pipes.
    Article Number: 900528
  • Non-return Valve
    Installation Kit for PR100-oRS
    Retrofitting kit for subsequent installation of non-return valve in PURAIN 100 o.RS.
    Article Number: 210137