What is the normal maximum filtration rate for gravity filters, according to regulation?

The normal maximum filtration rate for gravity filters, as regulated, is typically established at 6 gallons per minute per square foot (gpm/ft²). This standard is significant because it balances effective filtration with the potential for issues that can arise at higher rates, such as decreased water quality and higher maintenance requirements.

Gravity filters operate based on the principle of gravity allowing the water to flow through a bed of filter media, which removes impurities. When the filtration rate exceeds the recommended 6 gpm/ft², it can lead to insufficient contact time for particles to be effectively captured, risks of filter media being disturbed, and potential breakthrough of contaminants.

Maintaining the filtration rate at or below this maximum is essential for ensuring optimal filter performance and water quality.