TREPIDATION FROM THE TAP; WARNING TO PREGNANT WOMEN ADDS TO MISTRUST ABOUT DRINKING WATER.

Byline: Jenifer Hanrahan Daily News Staff Writer

Not too long ago, a friend of mine watched agape as I filled my glass with tap water.

He looked downright horrified when I put it to my lips.

``You actually drink that stuff?''

Why yes, I do. I figure it's the only thing besides air I can get for free in this city. And who knows how long that will last?

There are two types of people in Los Angeles: Those who drink the water, and those who don't.

Anecdotal evidence and raw data suggest the former is the rarer breed nowadays.

The residential water treatment industry - whose manufacturers offer products ranging from simple filtering carafes and faucet attachments to more complex systems that treat water throughout the house - is expected to generate an estimated $1.8 billion this year, according to the Water Quality Association, a Lisle, Ill.-based trade association that represents manufacturers and distributors of water treatment equipment.

The bottled water industry is another huge market, generating $3.6 billion in 1996.

Fueling the growth may be incidents such as the tap water scare last week.

Los Angeles Department of Water and Power officials are advising pregnant women to boil their water as a precaution against a chlorine byproduct, trihalomethanes, found in tap water.

The announcement came in response to a study done for the state Department of Health Services that found pregnant women who drank five glasses a day of tap water with high amounts of trihalomethanes were nearly twice as likely to miscarry in the first trimester as those who drank less or those whose water had lower levels of the chemicals.

It's enough to give even devil-may-care tap water enthusiasts pause.

Alarmed perceptions

Polls show increasing numbers of consumers are worried about the safety of their drinking water, said David Mogollon, managing editor of Water Conditioning and Purification Magazine, a trade publication.

More than 75 percent of those surveyed last year by an independent market research firm for the Water Quality Association reported they had some concerns about the quality of tap water, ranging from taste and odor to contaminants.

Half of all Americans worried that their water contained substances that could make them sick. Eighteen- to 34-year-olds were most likely to worry about tap water quality.

So what's a human to do?

First, rest assured that tap water from public systems in the United States is by and large safe. The Environmental Protection Agency requires that the water be tested and treated in compliance with stringent requirements of the Federal Safe Drinking Water Act.

Second, forgoing water is simply not a healthful option. Doctors recommend drinking eight glasses a day for optimal body functioning. Pregnant women need water even more.

While researchers and government agencies try to sort out just what levels of what substances are good for us, water drinkers should know their options.

Most people begin by turning to one of several types of water filtration systems that remove different compounds from water. But before investing in a product, it's best to determine what exactly is floating around in your glass.

Get your water tested.

The Department of Water and Power sends an annual water quality report with your bill that breaks down everything in the water over a 12-month period.

Companies that sell water-treatment equipment often offer a free or low-cost water analysis. Keep in mind their tests are limited mainly to taste, odor and chlorine - and the companies making the offers have a financial incentive in the outcome.

For an assuredly unbiased report, you can have your water tested by a state-certified laboratory. While you can't test for everything - the cost would be prohibitive - you can have the water tested for common contaminants. The state Department of Health Services offers referrals at [phone].

Solutions

If your water doesn't meet your standards, there are several treatment options:

Carbon filtration: This is the most popular form of home water treatment. The simplest version is the carafe, or pitcher, that removes residual chlorine, chlorine byproducts such as trihalomethanes, pesticides, taste and odor compounds, and, depending on the model, lead. Cost of a carafe is about $20 to $30.

Carbon filtration systems can also be installed on the faucets, under the sink or on the counter top. One or more specialized filters remove sediment, organic chemicals and lead. Cost is about $20 to $100.

The amount of contaminants the filter will remove varies by model. Also, many of the systems need to have their filters replaced frequently. If you don't follow the recommendations, the filters won't do you much good.

Reverse osmosis: This filtration system, usually used in conjunction with a carbon filtration system, forces water through a membrane that can remove additional contaminants, including nitrates and heavy metals such as mercury and cadmium. Cost is about $120 to $200.

Distillation: This process works by heating source water into steam, then passing the steam through a condensation coil, where it's cooled and condensed into drinking water. Distillation removes minerals, some taste and odor compounds and bacteria (the latter only if the water is promptly refrigerated).

The price range is $100 for a counter-top unit to $1,000 for a larger unit.

Boiling: This is a time-tested, inexpensive option for killing bacteria and parasites. Boiling water for at least a minute will also remove much of the chlorine and chlorine byproducts.

Much of the chlorine will also dissipate if you allow water to sit in an open container for 24 hours before drinking it.

Bottled water: In 1996, the Food and Drug Administration instituted federal standards for bottled water, making it one of the most heavily regulated food products. In fact, the national Centers for Disease Control and Prevention recommend that people with weakened immune systems, such as the elderly or people undergoing chemotherapy, drink bottled water treated by reverse osmosis or distillation. You can also check the label for ``one micron absolute'' filtration, which can remove substances such as Cryptosporidium, a pathogen that can cause severe cramping, diarrhea and even death.

There are many kinds of bottled water to choose from.

Artesian water comes from a well tapping a confined aquifer (an underground layer of rock or sand with water above it.)

Spring water must come from an underground location that flows naturally to the surface. The water can be collected only at the spring or through a bore hole tapping the underground source.

Mineral water must come from a protected underground source that naturally contains at least 250 parts per million of dissolved minerals. Water that contains less than 500 parts per million must state ``low mineral content'' on the label.

Sparkling bottled water is naturally carbonated.

Purified water or demineralized water must be produced by a process such as distillation or reverse osmosis that removes chemical contaminants and pathogens. It contains no added substances.

For more information about water safety, call the U.S. Environmental Protection Agency's Safe Drinking Water Hotline at [phone].

CAPTION(S):

3 Photos

PHOTO (1--Color--Cover) Tapped out: allay worries about drinking water with ways to take out the toxins.

Phil McCarten / Daily News

(2) no caption (Water bottles)

(3) Reverse osmosis removes salt and dissolved impurities at the tap.