As many as 90% of all residential water heaters manufactured
between 1993 and 1996 may be affected by faulty polypropylene dip tubes, reports an
article in Professional Builder. The dip tubes either disintegrate into
small pieces or into a white sludge that can clog plumbing fixtures and strainers on
appliances (such as dishwashers and washing machines). The American Water Works
Association (AWWA) reports that the debris is nontoxic. However, the disintegrating
dip tubes do reduce water heater efficiency, as cold water is allowed to be deposited at
the top of the tank where it is harder to heat and acts to dilute the outgoing hot water.
According to Energy Design Update, Reliance, A.O.
Smith, State, Rheem, Bradford White, and Jackson water heaters are affected. Toll-free
numbers for some of the above mentioned water heater manufacturers are listed below:
A.O. Smith (800)323-2636; Rheem (800)621-5622; State
(800)821-2019; Bradford-White (800)531-2111.