What size water filter do I need?
Posted on July 12, 2011
Once you’ve narrowed down on what type of filter you need, you must also figure out the size of the filter you need.
- Application of the filter: Firstly, determine the application of the filter. E.g: you may be using the filter for drinking water that will not need more than a 2 gallon per minute flow rate. On the other hand if you are using the filter as a whole house filter, you may need a flow rate of over 20 gpm.
- Preferred pressure drop: Secondly, determine the preferred pressure drop as per your needs. Although the application of the water filter may differ from user to user it is generally advised that consumers keep the pressure drop on a new cartridge below 2 or 3 psi. This is referred to as the clean pressure drop.
- Filter size: Finally, you need to select a filter size that allows for your desired water flow rate while maintaining the preferred clean pressure drop.When in doubt, get the bigger water filter cartridge. If you get a filter that is too small, it will break down quickly and will not be effective as per your requirements. Longer filters last longer than shorter ones. A 20 inch water filter should be able to manage double the flow rate for the same pressure drop as a 10 inch water filter with the same filtration technology.If you really don.t want to risk buying the wrong filter or aren’t too sure, you may want to speak with a plumber. Plumbers usually charge more for water filters, but can provide valuable advice, they also take care of the installation.