Most states permit steel and concrete construction materials. All piping, joints, and fittings should conform to American Water Works Association (AWWA) specifications. Welded steel water tanks should confirm to American National Standards Institute (ANSI)/AWWA Standard D100. Factory-coated bolted steel tanks should confirm to ANSI/AWWA D103. Wire and strand wound, circular, pre-stressed concrete tanks should confirm to ANSI/AWWA Standard D110.