What’s in Your Water?

What’s in Your Water?

“We never know the worth of water ‘til the well is dry.” – Thomas Fuller, Gnomologia


Water is an important part of sustaining life on Earth. It’s used by almost every plant and animal species, it’s required for most of the cellular processes in our bodies, and more than a week or so without it and you’ll be dead. While water may be essential for life, what’s in your water is another story. Despite the vast modernization of our culture, we still seem to have trouble making clean, palatable tap water widely available.

Maybe the problem is that it’s free. People are clearly willing to pay more money for “cleaner,” better tasting bottled water, even with the deleterious environmental toll beget by billions of extra pounds of plastic waste. And most homes have some sort of water filter in the fridge, on the faucet, or under the sink. But, is it worth spending the extra money for cleaner, safer, better-tasting water? The short answer: yes. The long answer: keep reading.

With water covering 70 percent of the Earth’s surface, you’d think there’d be plenty of it to go around. The problem is most of that 70 percent is salt water which is of minimal use to us humans (though fish seem to love it). The majority of our tap water comes from a combination of fresh water reservoirs, lakes, and rivers, and reclaimed and remediated waste water. Using a complex system of underground pipes, water treatment facilities and municipal utility companies deliver fresh, clean drinking water to thousands of homes. Well, that’s what they intendto do.


Even high-tech filtration systems and advanced chemical treatments can’t eliminate every impurity. And by the time purified water travels from the treatment facility to your cup, it’s definitely gathered many of the contaminants listed below.

Pathogens. Fresh water is a wonderland for microorganisms like bacteria, parasites, and viruses. These charming critters include E. coliCampylobacter, and Giardia lamblia, which are infamous for the cruel things they do to your gastrointestinal tract (diarrhea, vomiting, bloody stool, etc.). Infestation with pathogens is caused by contamination of drinking water with waste water. Most underground systems transport both, and old, leaky pipes and overflows from flooding can cause the two to mix. Treatment facilities do their best to kill any microscopic organisms, but no matter how hard they try some germs will inevitably survive the trip to your faucet.

Disinfectant by-products. One of the ways water reclamation facilities eliminate pathogens is through chlorination. Chlorine is a very good germ killer, but it can react with naturally occurring organic matter in the water to create bromate, chlorate, haloacetic acid, trihalomethanes, and other disinfectant by-products. According to some epidemiological research, these chemicals may be carcinogenic, although very few studies have examined their long-term effects. Regardless, the World Health Organization (WHO) and United States Environmental Protection Agency (USEPA) have set limits for the amount of disinfectant by-products allowed in public drinking water.

Heavy metals. Old, corroded municipal water pipes can cause more problems than germ contamination; they can also leach lead into tap water, and allow arsenic, mercury, and other heavy metals into drinking water from polluted ground water run-off. Both acute and long-term lead exposure can cause significant damage to many of the body’s systems and organs. Children are particularly susceptible to lead’s damaging effects on the nervous system and brain which can lead to severe developmental and cognitive disorders. Both mercury and arsenic are extremely toxic, potentially carcinogenic, and can cause a number of health problems. It’s a good idea to have your water – and yourself – routinely tested for heavy metals.

Other bad stuff. Polluted ground water run-off and waste water contamination are sources of several other impurities including pesticides from farms, Methyl tert-butyl ether (MTBE) from gas stations, perchlorates from agricultural fertilizers, and even trace amounts of prescription drugs from human waste. Any number of these impurities can be found in tap water in homes across the country.

A Solution

The only way to minimize contaminants is to filter water again before it you drink it, freeze it, or cook with it. There are a number of point-of-use filtration options on the market including reverse osmosis, ion exchange, activated carbon, and antimicrobial systems.

Reverse osmosis. In junior high science, you probably learned about osmosis, the movement of water from a region of high concentration to a region of low concentration through a semi-permeable membrane. Reverse osmosis is, simply, the reverse of that process, or the movement of water from low concentration (meaning a high amount of solutes; in this case, impurities) to high concentration (in this case, purified water). Reverse osmosis is great for removing salt, fluoride, calcium, and other mineral deposits in the water, but it’s also very wasteful (for every gallon of purified water, reverse osmosis creates about 5 gallons of waste water).

Ion exchange. This process uses small resin beads – about 1-2 mm in diameter – that freely and easily exchange ions with particles in the water. In ion exchange filters, the resin beads replace heavy metal contaminants in the water with safer ions like sodium or potassium.

Activated carbon. The activated (positively charged) carbon attracts the negatively charged contaminants and can reduce or eliminate bad taste, odor, chlorine, disinfectant by-products, pathogens, pesticides, and many heavy metals. Activated carbon is found in many popular water filters including Pur and Brita. When buying an activated carbon filter, be sure that it’s NSF/ANSI Standard 53 certified.

Antimicrobial. Many activated carbon filters contain silver to prevent the growth of bacteria, and ultraviolet light purifiers can be added to most home filtration systems to kill all types of microorganisms.

The WHO and EPA have established upper limits for impurities in drinking water, and municipal water companies are required to notify customers when levels of contaminants exceed these maximums. That doesn’t always mean it happens. The best way to keep you and your family safe is to filter your water yourself before you use it. It’s a good idea to have your water tested for any impurities and pick the best filter based on the results, or install a combination of filters to remove all contamination. You should also have yourself tested for heavy metals and pathogenic organisms to make sure levels in your body are within safe limits.