Each Black Berkey® water filter is designed to filter and purify approximately 11,350 liters of water before needing to be replaced. The pair of elements in all Berkey® systems (except the Go Berkey®, which has only one) will filter and purify approximately 22,700 liters of water before needing to be changed.

That's about 10 years of use for two Black Berkey® filters used in a system for a family of four, each consuming 1.5 liters of water per day.

Sample calculation to determine when to change the filters on a Big Berkey® system:

The Big Berkey® has a capacity of 8.5 liters. If the system is filled completely once a day, the calculation would be: 22700 / 8.5 / 365 = 7.3 years

This formula can be adapted to your model and daily filling habits to determine how often you should consider changing your filters.

Important note: the theoretical life span may vary depending on the water you are filtering. Not all water is equally loaded. This theoretical life is therefore not universal and is totally dependent on the formulation of each type of water and the maintenance given to the filters.

You can also apply this formula to PF-2 filters starting with the theoretical filtration capacity of 3800 liters.