1. Colour : Rapid sand filter is efficient in removal of colour. The intensity of colour is reduced below three on cobalt scale. Colourless waters can be produced if polyelectrolytes are added to water before filtration.

2. Taste and Odours : Taste and odours are not removed in rapid sand filters.

3. Turbidity : Filters can reduce the turbidity to the extent of 1 N.T.U. if the turbidity of applied raw water is less than 35 to 40 mg/l; which is possible due to chemically assisted sedimentation.

4. Iron and Manganese : Oxidised or oxidising iron is removed but it is less efficient in removing manganese.

5. Bacteria Removal Efficiency : In cases of low bacterial loadings, it removes bacteria to the extent of 90 - 99%. In comparison to slow sand filters, rapid filters are less efficient. Chlorination is recommended after filtration.

6. Wash Water Consumption : The filter is said to be efficient if wash water consumption does not exceed 2% of the filtered quantity.