Is My Well Water Contaminated?

Unlike municipal water, private wells aren’t regulated. It’s up to you to test your water and install equipment that removes dangerous chemicals and pathogens. There isn’t a universal well water treatment system, because each well is different. Even if you know what’s in your neighbor’s water, differences in local geology can leave different contaminates in your well.

If you want water that’s safe, tastes good and won’t harm your plumbing and appliances, you need a system tailored to your well. Here’s what you need to know about what can contaminate your well, how to interpret the results of your water test, and how to choose equipment to make your water safe to drink.

Dangerous Contaminants Found in Well Water

The main reason to treat your well water is to remove chemicals and pathogens that will make you ill, either immediately or after years of consumption. Levels of some contaminates, like microorganisms, can change over time. Others, like heavy metals, are usually steady, unless there are major changes to your local environment. Flooding can let runoff enter your well, while local construction may release new minerals into the water. Here are the primary contaminates you need to look out for.

Microorganisms: Bacteria, viruses and parasites present in water can cause infections and illnesses. Spikes in these pathogens can happen when there is an increase in well water due to snow melt, heavy rains or flooding. Waste can leak into ground water sources, especially if the well isn’t properly sealed, or it’s near septic leach fields.
Nitrates and nitrites: These chemicals are found in fertilizers and waste from animals and humans. Nitrites affect the body directly, reducing the blood’s ability to carry oxygen. Infants are particularly susceptible, and can suffer from methemoglobinemia, or “blue baby syndrome,” from oxygen deprivation. Nitrates can turn into nitrites in the body, as well as nitric oxide. Nitrates and nitrides also react with amines and amides in cells, forming N-nitroso compounds (NOCs,) which can cause cancer.
Heavy metals: These metals leach into the soil from manufacturing runoff, household plumbing, municipal waste and natural mineral deposits. Heavy metals include arsenic, antimony, cadmium, chromium, copper, lead and selenium, just to name a few. These contaminants cause a multitude of problems, including damage to the liver, kidneys, central nervous system and intestines, as well as acute and chronic toxicity, anemia and cancer.
Organic chemicals: These chemicals are used in a wide range of household products, as well as manufacturing and agriculture. Consuming high levels of organic chemicals may lead to damage to the liver, kidneys, central nervous system, circulatory system and reproductive system. This category of pollutants include volatile organic compounds (VOCs,) chlorine, trihalomethanes (THMs) and haloacetic acids (HAAs.)
Radionuclides: These are radioactive elements, including radium and uranium. Contamination is usually linked to coal and uranium mining, as well as natural deposits. Consumption can lead to increased risk of cancer and kidney damage.
Fluoride: In small amounts, fluoride prevents tooth decay. However, unlike fluoridated municipal water, groundwater can contain amounts far too high to be safe. This leads to skeletal fluorosis, which causes joint pain.
Extreme pH: Acidic or basic water isn’t a danger itself. However, extremely acidic or basic water can leach contaminates from pipes and solder joints in your plumbing system.
Iron bacteria: While iron and iron-loving bacteria are harmless, iron bacteria can create environments ideal for the growth of harmful bacteria. Iron bacteria convert dissolved iron into a precipitate that leaves a scum on the surface of water.
Manganese: This metal can enter groundwater from mining, manufacturing and agriculture, as well as mineral deposits. While it’s an essential nutrient, this metal is also a neurotoxin. Toxic exposure from water is rare in adults, but it can lead to memory problems. Even small amounts can interfere with early brain development in infants. This leads to behavior and learning problems later in life. This is a major health concern for babies fed a powdered formula mixed with contaminated tap water.

Contaminants that Cause Plumbing Problems and Bad Tasting Water

These contaminants won’t hurt you, but they can cause plumbing problems and make your water unpleasant to drink or use.

Sediment: Even if dirt, sand and silt aren’t harmful to your body, they are harmful to your plumbing. Installing a sediment filter removes large particles that can clog other water treatment equipment.
Iron: Even if you don’t have the right conditions to grow iron bacteria, this metal can cause problems with plumbing and makes water taste metallic.
Hard water minerals: Water that contains high levels of calcium and magnesium leaves behind mineral scale that clogs pipes and leaves a film around faucets and inside appliances. This scale buildup is a particular problem for appliances, where heat increases deposits to the point that it clogs lines. Hard water substantially shortens the life of washers, dishwashers and water heaters. These minerals also limit the effectiveness of detergents, so you have to use more soap to get things clean. These minerals also limit the amount of nutrients that can dissolve in water. This makes it more difficult to feed plants in a hydroponic garden.
Alkaline water: While extremely alkaline water can damage pipes, even water with a pH of 8.5 will taste bitter.
Salt: Salt in water doesn’t provide a significant source of sodium, but it can make water taste bad.
Sulfur: Hydrogen sulfur makes water smell like rotten eggs.

How Do I Test My Well Water?

Check your state’s environmental protection or Department of Natural Resources website for testing information. You always want to have your water tested by a state certified laboratory. You can also talk to your local filter equipment dealer. They should have tests available, and they’ll know what you need to test for in your area.

To set up an effective water treatment system for your well, you will need a battery of tests to get an idea of what’s in your water. While there are several tests you can do yourself using home test kits, it’s much easier to collect a sample and send it to a lab. Some tests require multiple steps and take several hours, increasing the chance for error. Once your water treatment system is operating, you’ll still need to test a few things to be sure your treatment system is working:

Coliform Bacteria: Yearly
Nitrates: Every two years
Manganese: Before you bring a baby into the home

Along with these scheduled tests, you should test your water after flooding, changes to the land, or changes in your water treatment equipment. It’s also a good idea to test your water if you notice changes to its taste or smell.

How Do I Interpret My Water Test Results?

The first test you get for your well will cover multiple pollutants and issues, including minerals, pathogens and pH. Some tests use direct measurements, while others are indicators of related problems. Test results are usually stated in milligrams per liter (mg/L) or micrograms per liter (μg/L.)

Coliform bacteria and E. coli: Not all coliform bacteria are dangerous, but if they’re present, your water is a prime breeding ground for dangerous pathogens. Some labs also test for E. coli. Only some forms of this bacteria are dangerous, but its presence indicates your water is the perfect breeding dangerous pathogens. The presence of either bacteria in any amount is considered unsafe. It’s generally recommended to get your water retested immediately after a positive result to be sure the first sample wasn’t contaminated.

Coliform bacteria and E. coli: Not all coliform bacteria are dangerous, but if they’re present, your water is a prime breeding ground for dangerous pathogens. Some labs also test for E. coli. Only some forms of this bacteria are dangerous, but its presence indicates your water is the perfect breeding dangerous pathogens. The presence of either bacteria in any amount is considered unsafe. It’s generally recommended to get your water retested immediately after a positive result to be sure the first sample wasn’t contaminated.
Nitrates: This is reported as nitrate nitrogen or both nitrate and nitrite nitrogen. If both are reported, the water is unsafe at concentrations as low as 10 mg/L, although it’s better if the water is under 2 mg/L. If only nitrate is tested, the level should be below 45 mg/L.
Lead and copper: Water is safe if it contains less than 15μg/L of lead and less than 1.3μg/L of copper
Chloride: At levels at or above 250 mg/L, water will taste salty, and plumbing corrosion will increase.
Conductivity: This measures the amount of dissolved minerals, but it doesn’t identify those minerals. If the result is more than double the hardness of the water, which is caused by calcium and magnesium, it indicates sodium, chloride, nitrate or sulfate contamination.
pH: This measures the acidity of water. 7 is neutral. Anything higher is alkaline, and anything lower is acidic. Ideally, water pH should be between 7.5 and 8.3. Anything less than 6 or greater than 9 may corrode pipes. Water treatment equipment also requires water to be within a specific pH range to work properly.
Hardness: This is caused by dissolved calcium and magnesium, which is usually picked up when water passes through limestone or dolomite. Ideally, these minerals should be between 150 and 200 mg/L. Higher amounts will lead to lime scale on pipes, which can damage plumbing and appliances. Extremely soft water can be corrosive. If you need to get a water softener to fix hardness, you’ll find most systems are rated in grains. One grain per gallon (GPG) is equal to 17.1 mg/L.
Alkalinity: Ideally, this should be between 150 and 200 mg/L. Lower values together with low pH indicate corrosion. Higher values can lead to scaling. Alkalinity is usually caused by water hardness. If it’s significantly higher than hardness, your water may be high in sodium. If it’s significantly lower than hardness, your water may be high in chloride, nitrate or sulfate.
Corrosivity Index: This is also called the saturation index, stability index or Langelier index. This measures the tendency for calcium carbonate (lime) to precipitate out of water. This index is based on pH, alkalinity, calcium content and conductivity measurements. Ideally, this should be between 0.5 and 1. If the index is over 1, scaling may be a problem. If it’s under 0.5, the water can corrode pipes and fittings. An index of -3 or +3 is considered severe, requiring major intervention to protect your plumbing system.
Manganese: For adults, water is safe if it contains less than 300μg/L of manganese. If you have an infant in the household, levels should be below 100μg/L.
Arsenic: Unlike other tests, arsenic levels are quoted in parts per million (PPM.) Arsenic levels of 10 PPM or higher are considered toxic. There are two types of arsenic: arsenic 3 (arsenite) and arsenic 5 (arsenate.) These molecules have different chemical structures, and require different approaches for treatment. If you have arsenic in your water, you must treat both forms.

More specific tests are available to isolate less common issues. Along with tests listed above, there are also tests for VOCs, iron, chemical oxygen demand, petroleum products and pesticides. If you live in an area with radioactive minerals, you may need to test for radon or radioactivity.

How Do I Treat My Well Water, Now That I Know What’s In It?

Most water treatment devices are effective at treating multiple problems. Since hard water is a common problem, most companies center their systems around water softeners. From there, you can choose to add equipment like UV filters and oxidizers to deal with specific issues. Your equipment dealer can help you choose the right equipment based on your water test.

Before you buy equipment, you need to check the condition of your well. Leaks from damage or an ill-fitting cap can let contaminates get into your water supply. The top of the well casing should be at least a foot above the ground to avoid contamination from runoff. If it doesn’t, you need to have it extended.

Here are the most common types of treatment equipment, and what they can do for your well water.

Sediment filter: This filter removes sediment, including large flakes of metals. These filters can remove particles as small as one micron, or one millionth of a meter. For comparison, a human hair is 40 microns wide. This isn’t small enough to remove small metal particles, salt or most pathogens. However, by removing large particles first, there is less material that can clog other filters in the system.
UV filter: This uses ultraviolet light to kill pathogens. The water must be clear for the light to be effective, so these filters are usually near the end of the treatment system.
Ion exchange water softener: This device replaces metal ions with sodium ions. This is mostly used to soften water, but it’s also effective at removing heavy metals, including arsenic 3 and lead, as well as nitrates. Occasionally, the filter media needs to be flushed with salt water. Some areas ban these filters to prevent water pollution from this salty flush water.
Nucleation (salt free) water conditioners: Also marketed as water softeners, these devices crystallize hardness minerals, so they can’t affect plumbing or soap. These filters do not remove heavy metals.
Oxidizer: This device uses air, ozone, chlorine or hydrogen peroxide to oxidize metals, forcing them out of suspension. These systems are also effective at removing sulfur. Chlorine and hydrogen peroxide systems also kill pathogens, and they can remove arsenic 5.
Carbon filter: Activated carbon has a surface area of 1,000 square meters per gram. As water passes through the filter, contaminates get trapped on the carbon’s surface. This filter removes chemicals, including VOCs and solvents.
Catalyzed carbon filter: This filter has a specially treated surface that removes heavy metals and chlorine, as well as everything removed by a standard carbon filter. Chlorine oxidizers always come with a catalyzed carbon filter to remove any leftover chlorine.
Reverse osmosis filter: This filter removes salt, nitrates and both types of arsenic. Due to their cost and water pressure requirements, these filters are only used for drinking water sources. These filters are usually part of a system that also has carbon filters, so you get the same benefits as house-sized systems.