Hidden Hazards: How Pipe Affects Water Quality
Everything affects water quality, from the treatment methods used by your water utility to the pipes hidden inside the walls of your home. Elsewhere we’ve discussed the advantages and disadvantages of specific piping materials. Now, let’s look at the most common types of plumbing pipe found in American homes and the effect they have on your household’s water quality:
Strong, durable and versatile, copper piping has been the preferred option for close to 80 years. The impermeable pipe protects drinking water from external contaminants, and the interior resists biofilm formation and bacteria growth. If your water’s acidic, it can leach copper from the pipe and increase the level of this heavy metal in your drinking water.
In use since the 1950s, CPVC (chlorinated polyvinyl chloride) is one of the most affordable piping options. Some studies indicate the interior resists biofilm formation better than all other piping materials. Tests conducted in California indicate it may leach into household water potentially harmful chemicals such as acetone, chloroform and methyl ethyl ketone.
Galvanized pipes are made of steel coated with zinc to protect against corrosion. Cadmium and lead are sometimes found, caused by impurities in the zinc coating that leach into the drinking water. The pipes may also release low levels of zinc and iron, which are generally not viewed as health risks.
Lead pipe can be found in any home built before 1986 when its use was banned. In babies and children, lead has been associated with delayed mental and physical development, learning difficulties and attention issues. In adults, it’s been associated with high blood pressure and kidney problems. Heat accelerates the leaching process, so using hot water for drinking or food preparations increases the health risk.
Since the 1980s, PEX (crosslinked polyethylene) tubing has been a popular piping choice. However, it’s known to release certain chemicals immediately following installation, and one study found that 11 specific compounds used to manufacture PEX were still present in the drinking water six months later. Outside contaminants can penetrate the tubing surface, and some studies indicate the interior becomes coated with biofilm faster than any other pipe material currently in use.
Homes built between 1978 and 1995 may contain polybutylene (PB) pipe. Chlorinated water can cause the inside surface to grow brittle and flake, producing drinking water with a cloudy appearance or strange taste. The greatest risk with PB pipes is they deteriorate from the inside out, so they appear fine even though they’re on the verge of failing. An experienced plumber can assess pipe integrity, so arrange for an inspection if you suspect your home has PB plumbing.