AWJ Service Co. family owned and operated since 1987 meeting all your backflow installation, testing, and repair needs. What is backflow? Backflow means there is a potential for contamination in the water distribution system. Common causes for backflow are water main breaks and high rates of water withdrawal (like fire fighting), however these incidents can be avoided with the use of backflow prevention devices. AWJ Service Co. works hard to prevent backflow through ordinances requiring backflow