Either single or dual grade sand is filled up in a pressurized vessel. Internally it is fitted with inlet distributor and a bottom collecting system. Externally, it is fitted with frontal pipe work and isolation valves. Pebbles and gravels are provided as the bottom layer under the sand bed of uniform size to support the sand bed. This filter removes mainly suspended impurities from the water source. Suspended impurities get trapped within the sand media when water having suspended impurities is passed through the sand bed and clear water comes out as the product. Backwash of the filter is to be carried out to remove these entrapped impurities from the filter, once it reaches to its maximum limits. This limit is governed by differential pressure across the filter.