Water Division Explains White Particle Presence

When residents find particles in their plumbing fixtures, they often bring them to the Water Plant Laboratory for examination. Typically, the material proves to be rust particles. This is normal, because water mains are made of cast iron, and the pipe’s surface rusts over time. Eventually, the rust flakes, and finds its way into household plumbing systems. While harmless, rust can clog the screens in faucets. The City’s annual hydrant flushing program serves not only to test fire hydrants, but also to flush out rust accumulation in City mains.

About 2 years ago, residents began submitting unusual off-white particles, which they removed from their faucet strainers. Accumulation occurred rapidly, necessitating weekly cleaning. Coincidentally, all of the homeowners reported that they owned new hot water heaters. Since the particles were not reddish in appearance, rust was immediately ruled out. The suspicion was that this was either calcium carbonate (‘hardness’ mineral naturally found in Lake Michigan) which had accumulated in the hot water heater (just as it will in a tea kettle left to boil dry) or breakdown of the hot water heater’s sacrificial anode. Such anodes are aluminum or magnesium rods which are built into hot water heaters to prolong the life of the steel tank. When cracks develop in the tank’s glass lining due to high temperatures, rust would quickly destroy the shell. Anodes prevent this by deteriorating instead. This results in a deposition of calcium carbonate and oxides of the anode’s metals in the bottom of the hot water heater. These are often light in color often a mottled white-gray-green.

This new substance, however was uniform in color. Tests designed to confirm normal suspicions failed. Unlike calcium carbonate or metal oxides, this material was insoluble, even in the strongest acids. Eventually, it was determined that an inferior substance had been used in the hot water heater manufacturing process. Specifically, the company which supplied a component of hot water heaters, the ‘dip tubes’ (see drawing), changed from metal to plastic (polypropylene). A dip tube’s function is to direct incoming cold water to the bottom of the tank to avoid mixing with (and chilling) the hot water as it is drawn from the top.

All hot water heater manufacturers (A.O Smith, State Rheem etc.) were affected, because plastic ages quickly in a heated environment. In this case, it crumbled into a soft white semi-gelatinous mass, and the deteriorated product floated to the top of the tank and out to the faucet. Now that the mystery substance has been determined, residents should consider if the following conditions are present in their own homes:

• Is the hot water tank relatively new, seven years or less?
• Is the substance appearing in the faucet light in color (egg shell)?
• Is it uniform in color?
• Does it float?
• Does it melt/burn if heated over a flame?
• Do you seem to have less hot water (shorter showers)?
• Is the screen in the HOT water supply to the wash machine plugged while the COLD is not?

A "Yes" answer to most of these confirms dip tube failure. Local plumbers are now familiar with this problem, and will replace the faulty tube with one constructed from more durable material. In fact, some hot water heater manufacturers are providing replacement tubes, and partial reimbursement for plumber costs.

Contact Information
For additional information, contact Water Plant Superintendent Don Jensen at (847) 433-4355.