He was talking about having less potable water and purifying sewage water into potable water.
Everyone should have a Big Berkey Water Purifier and extra ceramic filters for it - it purifies water wherever you find it, even dirty water in a ditch. Your water in your pipes can go away due to many reasons, so have a way to catch rainwater. Have barrels that catch rain water, and water off your roof going into a barrel or barrels. A Big Berkey will purify that water. A "Water Bob" is a food grade plastic bladder that fits inside your bathtub and holds 100 gallons of water. Fill that with your good water if you know there is a possibility of losing your piped water. It also has a pump to get the water out when you need it. It is in a small box when you buy it, very easy to store. It costs about $20.
