Tapid sand filter's performance can be affected by a number of factors

 A rapid sand filter's performance can be affected by a number of factors, including:

Filter media

The size of the filter media can affect how far suspended material penetrates into the filter. In a high rate filter, the top layers are coarser, allowing suspended material to penetrate deeper. 

Water quality

The quality of the raw water can affect the filter media that is best to use. 

Chemical treatment

The chemical treatment used can affect the filter media that is best to use. 

Coagulation

For rapid sand filtration to be effective, viruses and bacteria in the water need to be coagulated first. 

Temperature

Temperature can affect the effectiveness of the filtration process. For example, poliovirus was decreased by 99.8% in 15 days at 15–16°C, but it took 9 weeks to decrease by a similar amount at 5–6°C. 

Rapid sand filters are commonly used in water treatment plants after the sedimentation process. In optimal conditions, they can remove more than 99.5% of turbidity, but in poor conditions, they can remove less than 50%.