The Brita On Tap faucet filter, the most effective BRITA filter, may help avoid certain health risks like cancer, certain parasitic illnesses such as cryptosporidiosis and giardiasis, as well as kidney and liver damage and anemia by reducing such impurities as cryptosporidium, giardia, lead, asbestos, and benzene that may be present in your tap water. It also reduces the following harmful herbicides and pesticides. The On Tap faucet filter also eliminates bad tastes and odors by reducing chlorine (taste and odor) and hydrogen sulfide. Brita On Tap faucet filters should be replaced every 100 gallons or every four months, whichever comes first. If you're unsure how long it's been, not to worry--the Brita On Tap faucet filter has a built in filter replacement indicator that flashes red when you need a new filter.