We recently moved to an area of the country that has extremely hard water. I've been using the Brita water filter system here for a year now, and it absolutely does work. There is no trace of hard water deposits in our heavily used kettle, and the water tastes great. If you read and follow the instructions it does not leave little black bits in the water. I use the filter for a good six weeks (rather than the four weeks it calls for) before replacing it, and have still not seen any lime scale. I do a lot of comparison shopping, and Amazon is the cheapest place I have seen to buy them, as well. It is worth it.