Berkey offers a 2-year warranty on black filters. Mine failed test so needed replacement but were out of stock when other dealers had them. Upon complaining after several weeks and no filters, was referred to Berkey by NMCL for PRORATED replacement. Had to send filters to them and wait more time for them to get back with me to pay prorated price. Was also charged 1/2 of shipping charge (over $13) to get them to me. Don't think it's fair to gouge a customer to pay shipping when product was defective. This is the SECOND time I've had to return defective black filters. Unhappy customer!