Arsenic is toxic even at low levels, but it is hard to detect in water because you can’t taste it or smell it.

Arsenic is a chemical that can naturally get into your water by erosion or industrial runoff. Arsenic can cause cancer and hurt your immune system making it easy for you to get sick. This extremely toxic chemical is odorless and tasteless and must be identified only through a water test at a state certified lab.

Chlorine is often used as a disinfectant. It can make your water smell or taste like a swimming pool.

Chlorine is a common disinfectant that is found in swimming pools to keep the water from smelling bad from the bacteria that collects. Water treatment centers often add chlorine to their water to kill bacteria before it gets to your house, but too much chlorine can be hazardous to your health.

Why are there spots on my dishes, shower doors, and fixtures? You probably have hard water: water with a high mineral content.

Hard water is caused by a high concentration of calcium and magnesium in your water. They enter your water and accumulate as it runs over rocks and through the soil in the water’s natural cycle.

Sulfur in your water is easily recognized by its offensive smell. It smells like rotten eggs.

Hydrogen sulfide is a gas that gives off the offensive smell of rotten eggs. It is made by decaying vegetation and oil deposits under the earth’s surface. It can get into your water through corroding metal or a faulty water heater.

Excess iron in your water causes reddish, rust-like stains and makes your water taste metallic.

If iron is present in your water, it is because the water is flowing over iron bearing rocks, much like hard water. There are two types of iron contamination: ferric and ferrous. If you have excess iron, the best way to fight back is with a water softener.

Lead is not safe at any level. It is rarely a natural problem in the raw water supply, but rather an issue after the water leaves the treatment plant.

Lead is different from other contaminants because it rarely occurs naturally in the raw water supply. It is more likely to be a problem after the water leaves the treatment plant. It dissolves in your water from brass faucets, lead solder, or old lead piping. Lead exposure is not safe at any level.

Are there blue-green stains in your toilet tank or inside your fixtures? Does your water have a metallic taste? You might have low pH.

Anything that measures less that 7 pH is acidic. Airborne pollutants, decomposition of plant materials, or runoff from a mining spill can all cause your water to become acidic.

Does your water taste metallic, look brackish, or do you notice brownish stains? Similar to iron, manganese is a naturally-occurring mineral.

Manganese is a naturally occurring mineral that lives in sediment, rocks and soil. Manganese is an essential mineral, but a high concentration can be unhealthy to you and your home. The mineral leaves dark marks on water-using appliances and can stain sinks and drains.

Microbes, such as mold, algae, and bacteria, can make your water taste earthy, woody, or fishy.

Micro biologicals include any type of organic materials such as mold, algae, and bacteria. Private wells do not have the same requirements as water distribution centers. Water distribution centers are required by state and federal governments to provide biologically safe water.

Nitrate is a form of nitrogen that occurs naturally. It is odorless and tasteless. Excess levels of nitrate can be harmful to the health of both humans and animals.

Nitrates often enter the water supply through the use of fertilizer. Spring water is vulnerable to this type of contamination. This is because excess fertilizer isn’t fully absorbed by the soil or crops. People in rural communities should get their water tested for nitrates.

PFOS (Perfluorooctanesulfonic Acid) is a pollutant that is a bi-product of multiple industries and is associated with multiple health problems: chronic kidney disease, ADHD, thyroid problems, and more.

As the primary ingredient in multiple stain repellents and fabric protectors, as well as a bi-product of the commercial aviation industry, semiconductor industry, fire-fighting industry, and other industries, it is increasing difficult to avoid contact with PFOS.

Yet PFOS have been shown to cause multiple health problems, the most prevalent being chronic kidney disease. Your children are at risk for ADHD. It causes preeclampsia and fertility problems. It is also associated with altered thyroid hormone levels and elevated cholesterol.

A number of trace pharmaceuticals have been found in drinking water supplies. The impact of most of these "chemicals of emerging concern" on the health of people remains unclear...

The Environmental Protection Agency requires water treatment plants to test for nearly 90 contaminants. Pharmaceuticals aren’t on the list. Traces of pharmaceutical compounds have been found in drinking supplies across North America, but it’s not known how these pharmaceuticals are a risk to your health.

Are you noticing sand or dirt in your water or does it look foggy? This cloudiness is simply dirt or other solids suspended in your water.

Dirty, cloudy water is caused by sediments. They are from dirt, sand, or other inorganic matter running off into the water supply and wells. These materials float in the water and give the water a murky appearance. Sediment is mostly a visual concern, but can be removed by most filtration systems.