What is Flow Rate and why is it important?

Each water system is rated for a certain flow rate whether it is carbon filter, a UV disinfection system, or a water softener. In order for each of these system to remove the contaminants from your water, it will need sufficient contact time with the media for this chemical reaction to occur.

Flow rate is defined as the volume of water which passes through a given surface per unit of time, often expressed in gallons per minute (gpm). For example, a 10" x 2.5" 5 micron carbon block is rated for 1 gallon per minute (gpm). In order for this filter to mechanically  filter any contaminants, or adsorb any chemicals, it cannot flow more than 1 gallon per minute without reducing the filters efficiency.

What is the Service Flow Rate in my home?

How to use The Estimated Service Flow Rate Calculator:
To calculate an Estimated Service Flow Rate, select the number of fixtures and appliances that may run for more than 10 minutes at the same time.
To calculate an Estimated Peak Flow Rate, select the maximum number of fixtures and appliances that may operate at the same time.

What is Contact Time?

Contact time is the amount of time that the water spends passing through any media for the adsorption process to occur. Adsorption occurs when matter adheres to the surface area of a solid adsorbent material like granular activated carbon. This process is often confused with absorption, which is the process of assimilating molecules into a solid. To achieve proper contact time, the system, or filter calls for a specified service flow rate in order for the adsorption process to occur. The most common issue is that the water is flowing too fast, because either the system was not sized properly, or a flow restrictor is needed to slow down the flow and increase the contact time.

The diameter of the plumbing will limit the flow of water depending on the size of the pipe. The larger the diameter of the pipe, the greater the flow. The flow rate of 3/4" pipe is approximately 13.5 gpm, while 1" pipe flows at 21 gpm.