TANK COMPOSITION AND CONSTRUCTION: All 260 gallon tanks is made without BPA, is food safe, is high capacity and structurally sound, has two valves for easy use and water rotation, and fits through doorways. This tank comes with everything you need to store water at home: a food safe drinking hoses, a coupling, and long term water purification systems. The tanks are made as one composite piece at 700 degrees F by rotational molding. They are molded from a polyethylene composite independently certified by the National Sanitation Foundation (NSF). The tanks are molded as a one piece composite and have no seams. Some ask if there is a seam around the top, but there is not. The line that appears to be a seam around the top is a seam in the metal tank mold, not the plastic tank.