(Part 1 of a two-part series. See Part 2: Water filters inspire homeowner health.)
When I purified three quarts of tap water by distilling it, I got one pitcher of clean water and a residue of gray gunk. Naturally I wanted to know what I had saved my family from ingesting. Harmless mineral salts, my local water authority assured me.
If you tried the same experiment, your results would probably be similar. Despite the occasional sensational news story about drinking water contamination–the current one concerns the high lead level in Washington D.C.’s water–American water utilities produce safe drinking water. But, and there is a big but here, the water can become contaminated between the time it leaves a water treatment plant and comes out of your faucet. You may also have contamination issues if your drinking water source is a private well, increasingly a possibility as suburban development and new home building move farther out into rural areas. Ben Grumbles, chief of the U.S. Environmental Protection Agency’s Water Program, estimated that 15 percent or more of new houses now rely on private wells for their drinking water.
Given this, prudence dictates that you get your drinking water tested at a drinking water certified laboratory. If you have city water, your testing will not have to be as comprehensive because your local water authority is required to test the water it treats and publish the results in its “Annual Report on Drinking Water.” The EPA requires every water authority to test for nearly 100 substances; many water utilities monitor additional ones as well (mine monitors a total of 280). These results must be posted by July 1 of the following year (the 2003 test must be posted by July 1, 2004).
If you ask a lab to test for all the substances that might be in your water, or even the 100 that the EPA requires, the cost will be exorbitant, running to several thousand dollars. Rather going the whole nine yards, you should ask a lab to test for the substances that would most likely be there. Which ones are those? Richard Maas, a professor of environmental sciences at the University of North Carolina at Ashville and a leading authority on water treatment issues, said that 95 percent of the worrisome contaminants fall into five broad categories.
Of the five categories, Maas said the most serious–more than the other four put together–is lead because even in small amounts it can cause permanent neurological damage in children.
Lead is rare in source water, but it can get into your tap water in several ways and most of them are older house problems. Lead can leach out of the lead pipes that are common in the distribution network in older cities. Lead can also leach out of a lead service line from your house to the street, your brass water meter, which can be made with lead, lead solder joints in copper plumbing lines (commonly done until 1988), or in your chrome-plated brass water faucets (these were made with as much as 30 percent lead until 1988 and as much as 8 percent lead until 1998). A new house on a private well would not have this problem, but lead can be an issue if you are building in an urban area or tearing down part of an old house and building on top of it, for example adding a second story.
Maas, who has researched the lead issue for years, said that about 85 percent of the time, the lead test comes up negative. Of the 15 percent of homeowners who do have a problem, 85 percent of them (13 percent of the original group) can solve it by letting the water run for one minute before using it. Only 15 percent of the second group (2 percent of the original group) need to install a filter mechanism to remove the lead. But, Maas noted, the convenience factor–most people are too impatient to let the tap run for a full minute every time they turn it on–leads most homeowners to get a filter.
The second most serious contaminant to drinking water in America, in Maas’ estimation, is arsenic, a naturally occurring element that can contaminate ground water. If the drinking water in your new house will come from a well–either your own or the utility’s–you should get it tested for arsenic, he said.
Arsenic is well known as a poison when given in large doses. In the past few years, however, scientists have discovered arsenic is also a very powerful human carcinogen when ingested in very small doses over a long period of time. It’s about 200 times more carcinogenic for a person than it is for a mouse or a rat, Maas said. For this reason, the EPA has lowered the allowable amount of arsenic in drinking water from 50 parts per billion to 10 ppb, but many researchers, including Maas, think the standard should be lower because of arsenic’s extreme cancer causing potential.Maas said that 1 ppb was reasonable, but most labs cannot detect arsenic at levels lower than about 5 ppb.
Some areas of the country including parts of Arizona, New Mexico and Michigan, are known to have arsenic in ground water, but as this element is relatively common, anyone who gets their tap water from a ground water source should test for it, Maas urged.
The third contaminant on Maas’s list is drinking water by-products (DPBs), which are created when a disinfection agent such as chlorine reacts with a small amount of organic matter in the water. Since all drinking water contains some organic matter–for example, “fish pee and decaying leaves,” Maas said–the presence of DPBs is ubiquitous in municipal drinking water. The most common one is chloroform. Though the risk is very small, DBPs are carcinogenic, Maas said.
Changing the disinfection agent from chlorine to one that produces very little DPBs can have unintended consequences, however. When the Washington, D.C., water authority switched from chlorine to chloramine four years ago, the chemistry of the water changed and became more acidic. This in turn, engineers believe, caused lead in the lead distribution pipes to leach out into the water and reach excessively high levels. In Washington, the chloramines also caused lead to leach out of service lines, water meters, plumbing with lead solder and brass faucets that contain lead.
The simplest and most cost-effective way to remove chloroform and any other DPBs that might be in your drinking water is to fill a pitcher of water and let it sit for four or five hours, while the DPBs evaporate out of it, Maas said.
The fourth contaminant on Maas’ list is toxic chemicals that are discharged into rivers and lakes by manufacturers in industrial areas. Though individually each manufacturer may meet EPA’s discharge requirement, collectively it can be “a lot of stuff,” Maas said. Industrial chemicals can also affect ground water, in some cases over a very wide area. When MBTE, an additive to gasoline, leaks out of an underground storage tank, “it can flow for miles,” Maas said.
The last contaminant on Maas’ list is microbiological pathogens–cysts that cause cryptosporidium and giardia. These can contaminate surface water sources such as rivers and lakes, and the disinfection agents in the local water treatment plant do not always kill them. The cysts can cause a disease outbreak, but Maas characterized this possibility as a “pretty rare event.” Giardia can be treated with antibiotics, but there is no drug treatment for cryptosporidium. With healthy individuals, the fever and diarrhea quickly pass, but it is a concern for individuals with compromised immune systems, infants and the elderly.
Should you discover, after getting your water tested, that one or more of these contaminants is in sufficient amount to warrant a filter, you’ll have to do some additional research to find the right one–different filters remove different substances and there’s no “one size fits all.”
Web site information on drinking water:
The U.S. Environmental Protection Agency, www.epa.gov
The National Sanitation Foundation, an organization that certifies drinking water filtration systems, www.nsf.org
The Natural Resources Defense Fund, www.ndrc.org
Where should you get your drinking water tested? Your local health department should have a list of state-certified labs. A less expensive option with the added cachet of participating in an ongoing drinking water research project is to get your water tested at the laboratory run by Professor Richard Maas, a noted drinking water expert at the University of North Carolina in Ashville. For more information on this, go to Maas’s Web site, www.leadtesting.org, or write to CWLT, Environmental Quality Institute, UNC-Ashville, N.C., 28804.
Questions or queries? Katherine Salant can be contacted at www.katherinesalant.com.
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