Home improvement retailers such as Lowe's and industrial part specialty sellers such as Grainger sell copper tubing online. They sell a variety of pipe, tubing and fitting sizes for uses with heating and general plumbing applications.
As of 2015, it is important to buy copper tubing that is NSF/ANSI Standard 61 certified, in order to stand up to the rigors of heating and plumbing. Knowing local codes for mechanical and plumbing installations is a must when installing new or replacement systems. Repairs that do not meet local requirements can lead to major expenses and hassles at the next inspection, such as when a homeowner wants to sell his home.