If it hasn’t happened to you, you probably know someone whose home was damaged by a plumbing leak. According to the Insurance Institute for Business & Home Safety (IBHS), plumbing supply system failures are the leading source of residential water losses. Whether your home is brand new, decades old or just new to you, plumbing component failures can happen.
One of the most common residential plumbing system parts is the braided stainless steel supply line. This supply line has an outer covering made of braided stainless steel wires that protect an inner polymer tube which transports the water from the main plumbing system of the home to a sink, dishwasher, toilet, etc. The tubing may be single or multi-layered. This article will focus on the single layered polymer tubing design. Usually each end of the supply line has threaded connectors called coupling nuts, made from brass, steel, or plastic.
The designs and materials used in these products have changed over time based on new technologies, new materials, and even just product re-branding and marketing. Failures can arise from material, manufacturing, and design deficiencies despite the new designs and materials.
Consumers often purchase this particular supply line because they believe that the added strength of the stainless steel braiding will prevent any corrosion and potential hose bursts and leaks. Contrary to popular belief, stainless steel can and will corrode. The stainless steel braiding of these supply lines will begin to rust when exposed to chlorinated water, such as normal residential water. Over time and with exposure to the chlorinated water, the steel braids will corrode, and ultimately fracture. When a sufficient amount of the braiding has fractured, the internal tubing will herniate through the hole in the braiding and ultimately rupture.
WERC has conducted independent testing of the single layered tubing and found that the tubing alone cannot withstand normal water pressure. Therefore, when the reinforcing stainless steel braiding is fractured, the internal tubing herniates through the braiding opening and bursts. Water then will flow uncontrolled from the supply line resulting in damage to the home.
Not all stainless steels are the same but all stainless steels will eventually corrode, regardless of quality. When tested, the burst supply risers are commonly found to be made of grade 304 stainless steel. Grade 316 is more resistant to corrosion, however, even 316 steel can be of poor quality and may still fail.