July 18, 2000

Pursuing Purer Water:

Tap, Filtered or Bottled

What to Buy


Americans have long felt safe drinking their water out of the tap, and with good reason. For the most part, public water supplies and even well water throughout the country are highly unlikely to make anyone acutely ill.

The occasional failures of public systems to operate properly are few and attract national attention, like the sanitation breakdown in Milwaukee in 1933 that precipitated an outbreak of cryptosporidiosis, sickening 400,000 people and causing 100 deaths.

But in recent years concern has been mounting about less obvious potential hazards in drinking water, especially residues of pesticides and industrial wastes, lead from old pipes and compounds formed by chlorine and organic matter that are believed to be cancer-causing.

The concern about water safety has prompted millions of Americans to reject the water that comes straight from the tap, resulting in two new growth industries: bottled water and filtration systems.

In New York a section of the state's public health law and regulations established by the federal Environmental Protection Agency require the annual issuance of a public statement describing the city's water supply and the quality of its water. The current report states that the quality of the city's drinking water "remains high and meets all health-related state and federal drinking water standards."

But this raises a new question: are the standards high enough? Do the compounds called disinfection byproducts, or DBP's, that are formed when water is chlorinated pose a significant health risk, doubling a water drinker's chances of developing bladder cancer and perhaps causing some miscarriages? And what about turbidity, which results when particles of clay, decaying plants or even parasites become suspended in the water? In the same year as Milwaukee's water disaster, excessive turbidity in Philadelphia's municipal water led to scores of emergency room visits and hospitalizations, mainly of children and the elderly, who developed gastrointestinal illnesses after drinking turbid tap water.

Furthermore, standards set for water sent from the source do not take into account contamination from old lead pipes along the way to the tap. Lead levels should always be below 15 parts per billion, but to find out how much lead may be in your water, you must have it tested.

Getting the Lead Out

Meanwhile, if your tap has been unused for six or more hours, you can flush out the lead by letting the water run until it is cold (30 seconds to 2 minutes) before collecting it for drinking or cooking.

To find a certified lab that can test your water for lead, turbidity, arsenic, parasites and trihalomethanes (the most common DBP's), call the Environmental Protection Agency's Safe Drinking Water Hotline, (800) 426-4791. Likewise, if your water comes from a well, you will have to get it independently tested.

Selecting a Filter

"Filters vary widely in what they can remove, how much they cost and how expensive they are to maintain," states the June issue of Nutrition Action Newsletter, a publication of the Center for Science in the Public Interest in Washington.

There are table-top carafes that require frequent refilling, faucet-mounted units that can be switched from a filter to a nonfilter position and under-the-sink units that supply filtered cold water from a separate spigot or the main faucet. Prices range from about $20 to $500 and replacement filters can add up to $25 to $150 a year. Before shopping, determine what you want to remove from your tap water, what you can afford and the degree of convenience you desire.

A carafe uses a carbon filter that improves flavor and removes chlorine, DBP's and lead, but not microorganisms. Carafes are inexpensive and particularly handy for use in bathrooms and bedrooms.

Faucet-mounted, counter-top and under-the sink filters use more sophisticated carbon filters, some of which can remove cryptosporidium (look for a label stating NSF certified for Standard 53 cyst removal).

There are also rather expensive countertop, under-sink or basement systems that cleanse water by a process called reverse osmosis. The process works slowly and wastes a lot of water; it also removes beneficial fluoride from the water.

Finally, there are systems that distill water, taking out everything but pure water. Unfortunately, valuable minerals and fluoride, as well as flavor, are lost in the process. And water that is so "soft" (that is, free of minerals) is associated with an increased risk of heart disease.

Once in the store, check the available products for a certification statement by NSF International, an independent testing organization.

If all you care about is how the water tastes, its odor or color, look for a product that meets Standard 42. If you are also concerned about health effects, for example, from microbial cysts, lead, asbestos, pesticides and herbicides, mercury and turbidity, look for a product that meets Standard 53. The label will list only what the product is certified to do.

For $5 you can buy an NSF book, "Water Wise -- The Consumer's Guide to Safe Drinking Water," which lists all the units tested by NSF and what they remove. Write to NSF International, 789 N. Dixboro Road, P.O. Box 130140, Ann Arbor, Mich. 48113-0140, or call toll free (877) 867-3435. The Web site is www.NSF.org.

Be sure to follow the manufacturer's instructions on how often to change the filter cartridge. Failing to do so could result in a reversal of the desired effect, spewing unwanted organisms or chemicals into your drinking water.

Bottled water may or may not be safer than what comes from your tap. Most bottled water sold in the United States comes from underground springs that are supposed to be pollution-free. Mineral water is spring water that has a minimum of 250 milligrams of dissolved minerals in each liter, and sparkling water is spring water with added carbon dioxide to create the fizz. About a quarter of bottled waters, including Pepsico's Aquafina or Coca-Cola's Dasani, start out as municipal water, and they must say so unless the water is filtered or disinfected before bottling.

The Food and Drug Administration regulates bottled water and requires that all products be tested annually for chemical, physical and radiological contaminants. The International Bottled Water Association requires all its members to test annually for other contaminants still under review by the F.D.A.

Keeping the Standards

Unannounced inspections by the NSF determine whether all members of the association are in compliance. Bottled waters certified by NSF are listed in its "Water Works" guide. But keep in mind that certification does not mean a water is free of contaminants, merely that the level of contamination is below certain allowable limits.

Note, too, that, according to a recent study at Case Western Reserve University School of Dentistry and Ohio State University College of Medicine and Public Health, only 5 percent of bottled water tested contained the recommended levels of fluoride.

If children are given mostly bottled water, a fluoride supplement would be a sensible idea. The researchers also found that while most bottled water contained lower levels of bacteria than tap water, about 20 percent of the bottles tested had far higher bacterial counts.