Water–wherever we get it–is our most ubiquitous and essential health food. Can we trust what comes out of the tap to be safe, pure and good-tasting?
If you get your water from Lake Michigan through the city’s water treatment facilities as Chicago and 118 suburbs do, the answer probably is yes.
The millions of gallons that surge from the Jardine Filtration Plant north of Navy Pier and a smaller South Side treatment facility are among the most watched-over and cared-for public water supplies in the country, says Ellen Flanagan, chief sanitary engineer for the Chicago Water Department.
Yet what issues from the faucet is not without problems, mainly trace amounts of lead, depending on where you live and the composition of your water pipes. Also, there are no absolute guarantees that contaminants, such as the cryptosporidium parasite that killed 100 people in Milwaukee in 1993, couldn’t creep into Chicago’s water.
Risk of cryptosporidium in Chicago water is remote, says Flanagan. Plant operators take extraordinary measures, including daily testing, to keep the water clean.
Chlorine is the primary disinfectant for drinking water. It kills most pathogenic bacteria and is somewhat, though not totally, effective against cryptosporidium–but not against lead.
As water leaves the filtration plant it has almost no lead. But by the time it reaches faucets, lead can build up through pipes until it may exceed limits prescribed by the Environmental Protection Agency.
In toxic amounts (which are thousands of times greater than levels found in drinking water) lead can cause brain damage and other problems. But the effects of lead poisoning can be subtle; scientists advise keeping exposure to a minimum, especially for children.
Old-fashioned lead pipes and lead-based solder used in copper-pipe systems made before 1988 are primary contributors. Most are located between the main water line in the street and your tap, especially in older buildings. Chicago didn’t change its plumbing code regarding lead-pipe usage in service lines until 1986.
In 1992 a survey by Consumer’s Union found more than 50 percent of the Chicago homes tested showed lead levels of more than 5 parts per billion (ppb). While the EPA’s standards are 15 ppb based on water that has stood for several hours in the pipes, Consumer’s Union set the 5-ppb criterion for water that has run for one minute or longer. The 1992 CU survey was taken before the city began adding a mild phosphate polymer to the water supply to coat lead pipes and retard lead leaching.
A followup CU survey in 1994 showed Chicago had reduced that percentage of households with excess lead to 35 percent. Flanagan expects the system’s countermeasures to be more effective as time goes by.
Meanwhile, those who think they may have lead contamination should let tap water run before drinking it, especially if it has been sitting in the pipes for several hours, says Flanagan.
“Long enough to get it cold should be fine for most homes,” she says. Heat tends to speed up any leaching, so hot tap water shouldn’t be used for cooking.
People drinking Chicago water need not fear cryptosporidium she says, which has been traced to animal organs and feces and may come from farm runoff into rivers and then the lake. That may account for the problem in Milwaukee, where the river empties near the water-intake crib. Chicago’s river flows away from the lake, thanks to foresight by early engineers, and the water intakes are away from shore.
Still, the Centers for Disease Control and EPA have guidelines for those with weak immune systems. If their doctors advise it, they may want to boil drinking water for one minute to eliminate any traces of pathogens.
Alternative protections are bottled water or point-of-use water filters. But those methods have their own problems:
Water-faucet filters can guard against cryptosporidium and other contaminants if the filtering material can remove particles one micrometer or less, says the EPA/CDC guidelines. However, filters can collect sediment, which can recontaminate the water if they are not cleaned or replaced regularly.
Bottled waters from deep wells usually are not subject to bacterial contaminants or lead, though they may have other dissolved minerals. Not all are the same says the guidelines. “Bottled waters containing municipal drinking water derived from rivers and lakes are more likely to be contaminated. Any bottled water treated by distillation or reverse osmosis before bottling assures cryptosporidium removal,” it states.
There can be another problem with bottled waters, especially if they are not cared for properly, says Flanagan.
Tap water contains chlorine, which protects it against further contamination. But to improve their taste, many bottled waters eliminate chlorine or other disinfectants. Therefore, those bottles should not be left open, especially in warm weather when airborne pathogens may find them a wel-come breeding ground, she says.
Recently one private chemist, paid to check the bacterial levels in the tap water at different levels of a large Chicago office building, also took a sample from a bottled-water machine. The tap samples all were negative, he says, but the bottled water machine showed colonies of bacterial growth.
In addition to Chicago, 118 suburbs get Lake Michigan water processed through Chicago’s water department. Other suburbs use wells. To get the source of water for your suburb call the local water department or department of public works.
