The other key to having a good water system is to have as much capacity as possible. The brew reactor we're considering is a 5 gallon system. We need enough water to be able to fill the hot water tank (called the hot liquor tank) fill the mash tun/latter tun, provide adequate cleaning solution, etc. We decided on using two connected 55 gallon food grade plastic drums as they are not too expensive and provide more than adequate volume. A local homebrew supply store also happens to have these barrels in stock. The primary drum will contain two floater switches, one place at the top of the drum and one placed 1/5 the way from the bottom. The top floater switch will turn on an electromechanical valve that connects our main water line to the activated charcoal filter if the water level is below the height of the switch. Thus the system will always be trying to refill itself if it's below maximal capacity. The second floater switch near the bottom will act as an emergency notification signal in the event that the system is nearly out of water as we don't want the pumps to run dry. All of the pumps that we will be using aren't self priming (as it's cheaper that way) and thus having them run dry might burn their motors out. Dan and I are trying to decide if we can get away with using a standard RainBird EM valve instead of a more expensive one for the water inlet. The RainBird valve is made of PVC which would add chlorine to the system, but the AC filter would catch this added chlorine. However, this could burn out the filter faster. The question is how much faster.