Everywhere you look someone is clutching a bottle of “pure” drinking water, adorned with a label showing pristine, snow-covered mountains, or lush, northern forests. True, in some cases, people are responding to a fad. Increasingly, however, health-conscious Americans are reacting to serious concerns about the safety of drinking water available for their own consumption, and for the animals in their care.

Water plays a critical and complex role in the health of all mammals, constituting 55 to 75 percent of the body mass of warm-blooded creatures. A fetus develops in its mother’s amniotic sac and, from birth till death, water bathes and fills every one of a mammal’s billions of cells. In essence, the bodies of people, dogs, and other mammals are water-cooled engines. Releasing water vapor by panting and sweating through its paw pads induces gentle cooling in a dog’s body.

Water also lubricates a dog’s joints and muscles, cushions the spaces between each individual cell, and fills up all of the minute hollows in a dog’s body. The principal element of blood, water transports oxygen to all canine body tissues, and helps the white blood cells produced by a dog’s immune system move about its body and fight infections. Water provides an environment in which enzymes can digest food in a dog’s stomach, and convert it to energy for survival.

Water cleanses and detoxifies a mammal’s entire body. Known as the universal solvent, water is extremely stable and can carry many different substances, either in suspension or solution, without being permanently changed itself. However, this characteristic of water is a double-edged sword. Water’s ability to remove toxins from a body makes it capable of transporting quite a bit of toxic material into a body, as well.

All of the above are reasons why drinking the purest water possible is important for any person’s or any dog’s good health. It’s even more important for certain individuals to drink pure water. Any dog (or human) who has cancer; kidney, liver or immune dysfunction; or chemical sensitivity should receive the purest water possible. (See “Which Dogs Need the Best Water?” at the end of the story.)

What’s wrong with tap water?
Most adult Americans grew up without ever giving the quality of their municipal drinking water a second thought. It was readily available, it usually tasted fine, it didn’t smell bad, and it had been “treated” by the municipal water company, so it must be safe, right?

Yes and no. The Safe Drinking Water Act of 1974, the 1986 Amendments to the Safe Drinking Water Act, and the Water Quality Control Act of 1987 all authorized the Environmental Protection Agency (EPA) to set and enforce quality standards for drinking water. As a result of this legislation, water utilities concentrate on eliminating immediate and severe health threats from tap water, such as harmful bacteria. Their purification methods do not target the small amounts of chemicals that are harmful only after years of ingestion. The “safety thresholds” that scientists use to set “acceptable” levels of pollutants in drinking water don’t account for these small amounts of toxins consumed over time, or for the combined effects of small amounts of many toxins consumed together.

Because of the uncertain impact of these possible health hazards, and the lack of irrefutable proof of their long-term health consequences, water utilities set standards that reduce the risks of unhealthy water, but often end up as a compromise between what is safest and what is practical in the cost-conscious real world.

At the Second International Conference on Pharmaceuticals and Endocrine-Disrupting Chemicals in Water, held in Minneapolis in October 2001, researchers and scientists confirmed the presence of 129 widely used drugs in U.S. municipal wastewater, 49 at levels above a cutoff point for regulation.

Wastewater treatment plants remove solids and partly purify water before releasing it back into the environment, where it mixes with other water supplies in rivers, lakes, streams, and oceans. Substances such as caffeine, nicotine by-products, antibiotics, antidepressants, antacids, heart drugs, and more make it back into water supplies. It’s true; these substances have been found in low, but detectable levels in water supplies all over the U.S.

At the conference, New Mexico water engineers announced that they detected low concentrations of birth control hormones, the anti-seizure medicine Dilantin, the antidepressant Elavil, and the painkiller Darvon. In Atlanta, they found diltiazem and gemfibrozil (both heart drugs), and metformin (a diabetes drug), among other things.

Water treatment processes do not completely purify the water provided to residential consumers – not because they can’t, but because it is not cost-effective to do so. Typically, only about five percent of the water purified by treatment plants and delivered to our homes is used for drinking and cooking. Consumers use the rest – about 95 percent of the water from our municipal suppliers or wells – for bathing, washing, watering lawns, flushing toilets, and other household chores. It would be very expensive to apply the world’s most stringent drinking water standards to the entire water supply provided to a home. Instead, water managers are charged with the task of bringing water to “safe standards” – good enough to not make people sick.

Understandably, many people choose water prepared expressly for their families’ drinking water by purchasing it, or by removing the final traces of contaminants from the water just prior to its consumption, using a home-purification system. This is a wise choice, especially as scientists are just starting to realize that we may not know very much about the long-term effects of consuming even very low levels of contaminants. Holistic health improvement programs aim to reduce the level and type of pollutants introduced into a body from any source.

What’s in our drinking water
What potential, waterborne contaminants may be found in our drinking water, and how can dog owners remove them? The answer is not as simple as lugging home a few jugs of bottled water every week. First, let’s examine the kinds of health-threatening impurities that can appear in drinking water, and then evaluate the various water purification methods designed to remove them:

• Microorganisms: Bacteria, viruses, and parasites: Water treatment plants can easily determine the presence of bacteria in public water supplies and add chlorine to kill them. Viruses are much smaller than bacteria and more difficult to detect. Although disinfecting tap water with chlorine probably kills most viruses, it is difficult to test for their presence. Some waterborne viruses cause cold and flu epidemics in humans. Giardia and crypto-sporidium are the most common parasites found in drinking water. They occur in the form of hard-shelled cysts that protect them from chlorine, and they can cause mild to severe gastrointestinal problems in healthy people and animals.

• Minerals and metals: Some of these inorganic substances are considered mere nuisances, such as calcium, which causes hard water. Others, such as lead, mercury, nitrates, and aluminum are harmful to health. These substances can originate from naturally occurring sources, industrial discharges, runoff from urban or agricultural areas, or metal pipes and fixtures. Generally, water treatment plants reduce these substances to safe levels for immediate consumption; storage in contaminated pipes can recontaminate the water.

• Organic chemicals: Derived from plant or animal matter, organic chemicals include fertilizers, pesticides, petroleum-based fuels, preservatives, and dyes. In addition to the organic chemicals that have reached the tap water supply, the water purification process itself may create dangerous ones. Chlorine, which is added to virtually all U.S. drinking water, combines with organic chemicals and other natural debris to form trihalomethanes (THMs). Chloroform, the most common THM, is a known carcinogen.

• Radioactive substances: Radon, a naturally occurring source of radioactive gas, can become concentrated in well water that enters directly into a home water system before the water becomes exposed to air. Radon gas in water dissipates quickly when the water is aerated.

• Additives: Public water treatment facilities, from small community systems to large urban waterworks, all add substances to tap water. Chlorine, an effective disinfectant, also produces THMs. In 1947, the U.S. first introduced fluoride into drinking water to help prevent tooth decay in children. There has long been a controversy over this practice, with some scientists suspecting that long-term ingestion of fluoride may cause bone disease; other scientists refute this claim and defend municipal fluoridation. Although some American communities have discontinued this practice, it continues in many others.

• Pharmaceuticals and drugs: As much as 90 percent of the prescription and over-the-counter drugs humans consume are excreted in their urine and feces. Waste from farm animals is similarly loaded with antibiotics and fertility hormones. These contaminants lace drinking water in trace amounts with unpredictable, long-term consequences.

Is bottled water better?
While most people automatically assume that bottled water is from a better, more pure source than what comes out of their taps, this may not necessarily be true. Bottlers often derive their water from the same municipal water source thats fill the consumer’s tap, though they treat it in different ways, depending on how it will be sold: as basic drinking water, fluoridated drinking water, or distilled water.

Bottlers disinfect all three types of water with an ozone treatment or with ultraviolet light, and generally filter the water to remove dirt and some chemicals, take out some minerals, and aerate it to reduce odors. Because water tastes “flat” after its minerals are gone, some bottlers add back some minerals into their drinking water and fluoridated water to improve its taste.

They do not add minerals back into distilled water. Purified or distilled water represents the purest form of bottled water as it is essentially empty of foreign elements, including minerals. However, because distilled water acts as a highly effective solvent, some researchers refer to it as “aggressive” water. Over time, it can leach out any chemicals in a plastic container that are loosely bonded. Some holistic practitioners warn their clients away from buying and using distilled water sold in plastic jugs. The best long-term storage container for purified or distilled water is a glass or stainless steel jug or bottle.

Many bottled waters are identified as from a “natural source” – a naturally occurring spring or underground aquifer. But not all natural sources are safe or healthy. While natural spring water bottlers regularly test their water for the presence of several common contaminants, they generally do not test their water for a wide range of possible pollutants.

When buying bottled water, select a well-known brand of water bottled by a company that belongs to the International Bottled Water Association. They generally utilize the best purification methods, and have invested in the best quality control processes.

Buy bottled water from a store that sells a lot of water, and moves its inventory quickly. It will be less likely to harbor organic contaminants that multiply over time. Warmth and sunlight encourage the growth of microorganisms in water, so store bottled water in a cool, dark place. Responsible water bottlers do not make any claims of improved health resulting from drinking their water. They emphasize their water’s good taste and relative purity.

In some states, water sellers must label their products with levels of ash and/or minerals. If you are lucky enough to live in such a state, it would be wise to buy the product with the lowest level of ash or minerals. (The mineral-bearing properties of water are one of its least important attributes; most people and dogs receive all the minerals they need from a proper diet.)

Finally, keep a close eye on your dog to make sure he likes whichever water you choose. It will do him more harm than good if he doesn’t like the taste of your selection, and reduces his daily intake.

Purifying your own water
Home purification systems are a great way to produce fresh, healthy drinking water. Advocates of these systems like to say ominously, “Use a water filter or be one.” Don’t worry; after considering the effectiveness, cost, and convenience of home purification systems, it’s easy to find a system that will do the job.

Some companies that sell home purification systems will try to convince you that it is necessary to “test” your tap water to identify its contaminants before selecting a purification method. These dealers use inexpensive and generally ineffective, unreliable test kits designed to produce dramatic results for a potential customer.

Because of the vast number of possible pollutants, comprehensive laboratory tests are expensive. Most labs perform custom testing work for large water utilities, and are not set up to serve individual consumers. Several automated testing laboratories offer tests by mail for reasonable prices. However, testing may be an unnecessary expense if a consumer selects a comprehensive purification system.

There are four main types of home water purification systems: Filters, ultraviolet purifiers, reverse osmosis units, and distillers. We’ll describe each type and discuss their relative advantages and disadvantages.

• Water filters: Simple filters use a substance called a medium, which traps, absorbs, or modifies pollutants in the incoming tap water. Sediment filters use a medium that traps contaminants like a sieve. Municipal treatment plants have removed the coarse particles from water, but fine particles and viruses can remain. In a privately owned water system or well, if the water is dirty, a coarse filter will be required.

Mini-filters, such as the self-contained devices that fasten to the end of the kitchen faucet, offer very limited protection from water pollutants. Because of their miniature size, they do not contain enough medium, like carbon, for the water flowing through them to have adequate contact time to become purified. They are relatively inexpensive, but require frequent changing of the cartridge. Products such as the Brita Pitcher Filter also uses a carbon filter. Consumers who use these types of filters should trickle water through the filter slowly, and change the cartridge often.

Carbon filters are particularly good at removing bad tastes, smells, and organic chemicals from water, but they do not remove microorganisms or toxic minerals. Like most filters, a carbon filter accumulates pollutants within the filtering medium, so its effectiveness decreases with use. Also, when the water pressure changes quickly, pollutants can break away from a contaminated filter and enter the drinking water. Because the buildup of pollutants in the filter can support the growth of certain kinds of bacteria on the filter itself, the medium must be changed regularly.

This is true of sediment filters, too, which can remove bacteria and parasites from tap water. When bacteria and microorganisms are trapped on the surface of the filter, they form a film that eventually clogs the filter or harbors the growth of new bacteria. Some membrane filters can be cleaned, but most must be replaced at regular intervals.

Although sediment filters can remove toxic particles from water, these filters cannot remove dissolved toxins, especially metals. Special filter media, like alumina, attract and hold toxic metals, like lead, with their electric charge.

• Ultraviolet (UV) purifiers: These purifiers have a single purpose… to kill bacteria and viruses. Municipal and commercial water treatment managers accomplish this with chlorine; UV is a nontoxic alternative to chlorination. However, the purifiers are very specialized devices and, as such, are commonly used in combination with other purifiers, like filters. This layering of treatments quickly becomes costly. What circumstances warrant the use of a UV purification device? If a consumer is drawing tap water from a private system or well that is not chlorinated, then UV is one of the safest ways to disinfect drinking water.

• Reverse osmosis (RO) units: Osmosis is the tendency for a liquid of lesser concentration (more pure) to pass through a semi-permeable membrane into a liquid of higher concentration (less pure). A reverse osmosis unit, as the name suggests, forces water of lesser purity across a semi-permeable into another chamber of greater purity. The membranes used – generally made of cellulose acetate or polyamide resins – have only microscopic “holes” in them, allowing water molecules through, but blocking larger molecules. Forcing water from a “contaminated” state, like tap water, through a membrane and into a “pure” state is, therefore, the reverse of natural osmosis.

The RO membrane holds back a wide range of contaminants, making this system a good choice for home purification. RO units remove even dissolved impurities in water. Because there are several types of RO membranes to choose from when selecting an RO unit, consumers might consider testing their tap water to determine its mineral content. The test results will help to decide what kind of RO membrane is best suited for treating their home tap water.

RO units work with normal water pressure, they usually fit under the kitchen sink, they are quiet, and most require no electric power to operate. The membranes have a long useful life, but they can become clogged over time. Most RO units flush themselves out occasionally with tap water to reduce the replacement interval of the membrane.

Tap water runs through the RO unit slowly, then enters a holding tank to await consumption. If your need for pure drinking or cooking water suddenly increases, when you have a number of guests, for example, there may be a delay in providing drinking and cooking water from a small RO unit. Also, RO units cost more than sediment filtration systems.

Perhaps the most daunting disadvantage of RO units is that they use a lot of “contaminated” water to produce “pure” water; they recover only 5 to 15 percent of the water entering the system, and the remainder is discharged as waste water. This can add a load on small septic systems, or, even add a significant cost to those who pay for water.

• Water distillers: Today, home distillation units are rapidly gaining in popularity. Unlike filtration methods that remove impurities from the water, the distillation process removes the water from all of its impurities!

Distillers heat tap water until it turns into steam. Then it condenses the steam into water again. All pollutants are left behind, and the condensed water that results from the process is very clean. A few impurities, like some THMs, have a lower boiling point than water, and vaporize right along with the water. For this reason, many distillers use a small carbon after-filter that removes the few impurities that remain following distillation.

Because distilled water is so pure, many nutritionists refer to it as “empty” water. This characteristic makes distilled water an excellent cleanser and detoxifier, with plenty of “room” or “power” to carry away impurities from a person’s or a dog’s body. Detoxification is the most important function of water.

Some people complain of distilled water’s “flat” taste, which results from its lack of virtually any mineral content, and some animals avoid it. However, other people love its sweetness and the lack of mineral or chlorine taste, and some dogs prefer it. It’s totally a matter of individual preference.

Distillers use electricity, and create heat and humidity in their surroundings. Some units are fan cooled and can be a bit noisy. The units take time to process a tank full of water, and the drinking water comes out warm immediately after treatment. Most distillers include holding tanks where the purified water cools before consumption.

A 20-year-old distiller’s most recent batch of water is as pure as its first batch because there is no filter medium to degenerate each time it is used. With some maintenance to clean away mineral residue that has been removed from the water, distillers operate very consistently, and remain very effective over time. There are no filters or membranes to replace, except carbon after-filters, if desired, but the unit must be cleaned regularly, and large units can be costly.

I chose a home distillation system for my husband, my dogs, and me more than 10 years ago. It continually provides my family with delicious, pure water for drinking and cooking, and requires little maintenance. When I travel, I “crave” my distilled water, so, when I pack for a weekend at an agility trial, I always include a jug of home-distilled water for me and my Border Terrier.

Worth the effort
Selecting a home water purification system can be a daunting task. But remember: Any purification devices, properly maintained, will produce healthier water than tap water. Dog owners who feed a natural diet, and seek out holistic healthcare alternatives for the dogs in their care, can supply an added measure of protection to their dogs by providing the purest possible drinking water.

-by Lorie Long

Lorie Long is a freelance writer and avid agility competitor living in North Carolina.