I don't intend to hammer away on this point, because everyone who visits this blog generally knows how important it is to have access to clean water, and this subject has been covered many times from many different angles. Many of us have several hundred gallons of water stored away in containers, some more portable than others. Some plan to rely solely on a Berkey water filtration system to filter surface water collected from ponds or rain catchment barrels. While the Berkey filters are excellent and water storage is a must, having these will not be good enough in a prolonged grid-down scenario. Your water storage may run dry, and your Berkey filters have a limited lifetime and may not be able to handle long-term filtering.