Common Contaminants in Drinking Water and Ways to Avoid Them

With the latest controversy over water quality in Flint, Michigan, have you stopped to wonder what’s in your drinking water?

Those of us who live within urban areas in the United States usually get our water from municipal water systems. These facilities take water from lakes and rivers, filter and disinfect it, and pump it to our homes in a form that is generally safe to drink without any further processing. The Environmental Protection Agency as well as state agencies regulate what can be in our drinking water and require regular testing of our water supplies.

Even with routine monitoring, it’s possible that contaminants can enter our water supply. Furthermore, if you live in a rural area and depend on well water, or you like to travel abroad or go camping, you can encounter unsafe water.

Let’s take a look at some of the common water contaminants, how water is treated, and how you can protect yourself and your family.

Sources of Water Contamination

Most of our drinking water originates from rivers and lakes near where we live. Depending on where it is, the water may pick up bacteria and other microorganisms as well as pollutants from industry, agriculture, roadways, and other sources. As water flows through rocks, sand and soil, some of the foreign material gets filtered away, but those rocks can also leach minerals into the water.

Before this water is safe to drink, it must go through several stages of processing. Water will be filtered to remove particulates that make the water cloudy; disinfected to kill any living organisms; and treated to remove concentrations of minerals and chemicals that exceed federal and state health standards.

How Dangerous Are These Contaminants?

The EPA regulates over 80 different potential water contaminants that may pose health risks. Some of these substances may cause acute illness, such as what might occur from bacteria or other microbes, like E. Coli, which may cause illness and even death. Other contaminants, including lead, pesticides and radioactive elements, build up in the body over time and may cause organ failure, birth defects, developmental issues in children or cancer. The EPA requires that all municipal water facilities regularly test for these contaminants to ensure our water is safe to drink.

What’s in My Tap Water?

Although agencies regulate levels of contaminants in water coming from municipal water supplies, it’s a good idea to know what can be found in the water that comes out of your faucets. Below we’ll look at a few things that homeowners should keep in mind.

Contamination From City Water Supplies

Most municipal water treatment plants will filter water for particulates, and then apply disinfectants and chemicals to remove harmful microbes and other contaminants from water. Barring equipment malfunction, flooding or human error, water that comes from your city water supply should be safe to drink.

However, to produce clean water, certain chemicals must be added to the water supply, and some consumers prefer to remove these chemicals before consuming the water.

The most common additives to our drinking water are chlorine, chloramines, and fluoride.

Small amounts of chlorine are routinely added to drinking water supplies to kill harmful bacteria, viruses and other microbes. While in these quantities the chlorine is safe to consume, many people dislike the taste and smell. Showering in chlorinated water may also cause dry, itchy skin. For these reasons, some people use inexpensive activated carbon filters (in water pitchers or attached to faucets) to remove the chlorine from the water.

Chloramines are another substance used to disinfect water, although they are significantly less effective than chlorine. They are formed when chlorine comes into contact with ammonia. Many municipal water systems either treat water with chloramines or first treat water with chlorine and then later add ammonia. Like chlorine, it is easy to chloramines with charcoal filtration.

Because these chemicals may harm fish, people with fish tanks or outdoor ponds should take special care to treat their water either through filtration or using special chemicals made for this purpose.

What About Fluoride?

In some forms, fluoride is toxic. However, fluoride in its mineral ionic form is found naturally in our bodies, and supplemented in very small quantities, it may be beneficial for reducing tooth decay. For this reason, many municipalities regularly add fluoride to drinking water.

Due both to naturally occurring deposits as well as malfunctioning equipment or poor monitoring, some water systems have tested for higher than recommended levels of fluoride. Furthermore, the EPA conducted research that shows that fluoride exposure among the population has increased significantly in the last 40-50 years, through a combination of fluoride found in drinking water, toothpaste, certain medications, and Teflon coating on nonstick pans.

Long-term overexposure leads to tooth enamel destruction, brittle bones, and joint pain. As a result, many people choose to reduce their exposure to fluoride, and some have campaigned to remove it from drinking water.

Removing fluoride is more difficult than removing other contaminants. Reverse osmosis is a good option, but expensive for the average homeowner. You can also filter out fluoride through deionization in some water softeners and activated alumina filtration.

Contamination From Pipes

The two most common contaminants in our drinking water are copper and lead. Rather than coming from our municipal water supplies, these minerals leach into drinking water from the plumbing used to bring the water into the building.

Lead poisoning can occur gradually and often without warning. Although lead has a bit of a metallic, sweet taste, it can be difficult to recognize in drinking water. It gets into our water through corrosion of older pipes, as well as lead solder and brass fixtures. Symptoms of lead poisoning include vomiting, constipation, stomach pain, and irritability. Over time, lead may cause brain damage, as well as impair kidney function, damage the nervous system and affect red blood cells. Children are at greatest risk as they absorb lead at significantly higher levels than adults, and for children, in addition to the other risks they can experience lowered IQs and developmental delays.

Copper is another contaminant that can enter our water supplies through corrosion. While humans need trace amounts of copper in our diets, too much can be toxic. Like with lead, copper poisoning may cause nausea and stomach pain, vomiting and other flu-like symptoms, and long-term exposure may lead to liver poisoning, kidney failure and anemia.

Well Water Contaminants

People who obtain their water from wells don’t have to necessarily deal with chemicals from other sources, but they must be just as concerned about their water quality. Well water may have high levels of dissolved minerals and chemicals leached from surrounding soils, agricultural runoff, and naturally-occurring but unsafe microbes.

Some of the biggest dangers lurking in well water include arsenic, a toxin that can leach from natural deposits or enter ground water from sources as varied as mining, oil and gas extraction, pesticide use, and treated wood. It is both tasteless and colorless, so regular chemical analysis is necessary. Fertilizers and pesticides, as well as nitrates and nitrites from fertilizers, animal waste and septic tanks, present another common hazard for well water. Finally, well water must also be disinfected to prevent consumption of a variety of microbes, including fecal coliform bacteria and E. coli, two bacteria that may enter groundwater from agricultural runoff.

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Why Was There Such a Problem With Lead Poisoning in Flint, Michigan? Can That Happen in My Town?

For many years, the people in Flint, Michigan got their water from the Detroit Water and Sewerage Department, with the water coming out of Lake Huron and the Detroit River. Due to budgetary constraints, the city changed its water source to the Flint River, a water supply with considerable industrial pollution. The new water was heavily polluted and far more corrosive. Significantly, when it went through the water treatment process, there was no addition of the chemical orthophosphate, which deposits phosphate within pipes to prevent corrosion. As a result, lead leached from the old plumbing into household water supplies.

Because of this error, as many as 12,000 children in the Flint area may have dangerously-high levels of lead in their bloodstreams. While this issue was rectified in December 2015, it’s unclear how long it will take for a sufficient coating to build back up in the pipes.

This situation in theory could occur in other communities that have older plumbing systems, but the Flint River was a particularly poor source for drinking water, which compounded the problem. Typically there are a number of safeguards and policies in effect, as well as heightened awareness, that should prevent other cities from experiencing similar issues.

How Do You Make Water Safe to Drink?

Treating water, both by municipal facilities and at home, will include one or more of the following processes:

• Disinfection

  Disinfection, which kills off harmful microbes in the water, can be achieved by adding chemicals such as chlorine or iodine; exposing water to ozone produced by high-voltage currents; exposing water to ultraviolet (UV) light; or boiling for at least three minutes. Of these processes, ozone is the most effective at removing both biological contaminants as well as mineral and chemical substances, but is only available at water treatment facilities.

• Filtration

  Filtration can remove a wide variety of contaminants. Options include mechanical filters that remove suspended contaminants, such as sand, from the water; activated carbon filters that absorbs chlorine and organic compounds; and oxidizing filters and neutralizing filters. Most filtration can’t completely remove microorganisms or other chemical and mineral contaminants, so it typically will be used in combination with at least one other water treatment method. Filtration units are suitable for general household use, however, and can remove unpleasant tastes and odors from treated water.

• Reverse Osmosis

  In this method, water is pressurized and then forced through a very fine membrane. Up to 90% of contaminants are left behind in the reverse osmosis process. Frequently RO units are used in conjunction with mechanical filtration that removes larger particles, and some also filter water through activated carbon to remove remaining impurities. These units, while pricey, are suitable for installation in a home, often under a kitchen sink. One caution is that more than half of the water used in these systems is discarded, which can lead to high water bills and may not be suitable for regions that experience regular drought conditions.

• Distillation

  One of the most effective means of purifying water is distillation. In this process, water is heated until it vaporizes, leaving behind nearly all contaminants. When the water recondenses as liquid water, it is free of most impurities. Some solvents and other chemicals can remain under some distillation processes, though commercial water distillation is more thorough than home distillation. Because dissolved minerals are also removed in the process, distilled water tastes flat and will not contain essential trace elements required for a healthy body. (We therefore recommend not using distilled water as a primary source of hydration.) While distillation units can be purchased for home use, they can be expensive and process water very slowly. Some states may also regulate purchases of distillation units because of the potential for some units to be used to distill alcohol.

• Ion Exchange (Water Softeners)

  Excess mineral content—particularly calcium and magnesium, as well as iron, manganese and other elements—can produce water that has an unpleasant taste, doesn’t work well with soaps and detergents, and leaves mineral deposits in pipes, faucets, and water heaters. Ion exchange works by replacing the minerals in the water with sodium. Water softeners are common in many households, but do require regular maintenance and recharging with sodium chloride (salt). These systems also raise the sodium content in drinking water, so it’s worth keeping this in mind for household members on low-sodium diets or who have heart disease.

What Can You Do to Ensure Your Water is Safe?

First, if your water is discolored (usually rust-colored or yellow) or has an unusual odor or taste, stop using it immediately. Particularly after heavy rains, but occasionally at other times, water treatment plants may have temporary issues with treating water. Check with a city information hotline or local media to see if a boil water or other water advisory has been issued.

Next, consider installing a water treatment system in your home, and be sure to bring water filtration and disinfection systems on camping and hiking trips.

If you want to treat your water at home, you have two options:

• Point of entry systems:

  These are water treatment options that are installed at the water meter or storage tank, and treat all water entering your home. They can be relatively expensive to install and maintain, but ensure that minerals and other contaminants are removed from the water used for cooking and bathing as well as in appliances such as washing machines, hot water heaters, and ice makers.

• Point of use systems:

  These are much less expensive than point of entry systems, and include filtration units on kitchen faucets, showerheads, or in refrigerators. You can also purchase water pitchers or countertop filtration units. Most of these incorporate activated charcoal filters that need regular replacement. You can also install a reverse-osmosis unit under the sink that will filter your water for cooking and drinking.