Abstract: A filter apparatus for filtering gross pollution from storm water for fitment to storm water traps located at the entry and exit of storm water, underground and drainage systems. The apparatus includes a gross pollution filter basket located below the entry level of storm water into the trap so as to provide a bypass channel to allow a volume of storm water to pass through the trap. SA storm water bypass means is arranged to restrict entry of incoming storm water and gross pollution into the bypass channel while the combined pressure of storm water and gross pollution inside the trap is such that storm water can still pass through the filter basket.The bypass means which acts like a one-way valve is also arranged to allow storm water and gross pollution to pass into the bypass channel when the combined pressure of storm water and gross pollution inside the trap is such that the storm water is restricted from passing through the filter basket.

Abstract: A water filter arrangement (10) for trapping gross pollutants flowing in a storm water system is provided in-line or at end-of-line of a storm water pipe. The arrangement comprises an inlet (14) and an inlet area (18) which directs incoming water (16) into a filter (20). The filter traps entrained gross pollutants and filtered water exits the filter via filter outlet (50). The outlet (50) and surrounding walls (58 and 57) are shaped to create a flow of filtered water which forms a water barrier which restrains the flow of water and gross pollutants from the inlet (14) to the outlet (52). The water barrier is located between the inlet (14) and the outlet (52) preferably closer to the outlet than the inlet. As the filter (20) becomes full and the flow of filtered water exiting the filter decreases the water barrier subsides.