What is a UV filter?

It is not a filter. UV kills bacteria with a lamp which radiates ultraviolet. That is it.  If you are on a public utility water supply you do not need UV because your water has been disinfected with chlorine. The remaining issue is cysts such as cryptosporidium, giardia etc which are chlorine resistant and our models Pearl-B, Pearl-DSC, Pearl-DUC and (for the larger household) Oyster-TBC will filter out cysts.

If you have a private water supply (private wells, boreholes, streams etc) you have very different problems and need to click on "PRIVATE Water Supplies" in the index on the left.