what's in water

It’s probably been a while since you learned about water in science class. And if you don’t deal with chemistry every day, you may not have a clear idea of what’s really going on with the water in your home. For starters, what’s in water, and why do we call it H2O? Is it always as clean as it looks? And, if not, how can you ensure purer, safer water in your home?

The Structure of H2O

Water is a simple molecule made up of three atoms: two hydrogen atoms and one oxygen atom, which is why we also call it H2O. The hydrogen atoms are bonded to the oxygen atom through covalent bonds, which means they share electrons. This creates a V-shaped molecule, with the oxygen atom at the center and the hydrogen atoms on either side.

The structure of H2O is important because it gives water its unique properties, such as its ability to dissolve many substances and its high boiling point relative to its molecular weight. However, this also means that water can carry many other compounds in addition to pure H2O. For instance, the water that comes from your taps may contain various minerals, bacteria, heavy metals, parasites, and chemical additives.

What’s in Your Home’s Water?

It’s not unusual for water to contain traces of other substances, whether it’s from a natural source or pouring from your kitchen faucet. Though municipal water supplies in the US are treated and filtered to meet safety regulations set by the Environmental Protection Agency (EPA), some things may slip through the treatment process, while others may sneak back into your water as it travels from the treatment center to your home. For instance, leaky or corroding pipe systems could expose your water to metal particles, agricultural runoff, or other contaminants in the nearby soil.

Well water can also be impacted by local conditions, especially if not properly filtered. Because a well pulls your supply of H2O from the groundwater around it, anything present must be treated and filtered before the water is used in your home.

Typical Water Contaminants and Additives

Depending on where you live and where your water comes from, there are a number of common contaminants and additives that could be in your water supply without you even realizing it.


Not all drinking water contains fluoride, but in many countries, fluoride is added to drinking water to help prevent tooth decay. In the United States, the decision to add fluoride to drinking water is usually made at the state or local level, rather than at the federal level, and not all communities in the United States add fluoride to their water supply. According to the Centers for Disease Control and Prevention (CDC), as of 2018, nearly 74% of the U.S. population that receives water from public water systems had access to fluoridated water. The level of fluoride added to drinking water in the United States is typically between 0.7 and 1.2 milligrams per liter (mg/L), although the exact level can vary depending on factors such as climate, water source, and other factors.

It is worth noting that excessive fluoride intake can lead to a condition called fluorosis, which can cause mottled or discolored teeth, so it is important to monitor fluoride levels in drinking water and dental products. But, generally speaking, fluoridated water is a good thing! In fact, the addition of fluoride to drinking water has had a huge, positive impact on reducing tooth decay in America. The CDC even named fluoridation as one of the greatest public health achievements of the 20th century.


There can be sodium in drinking water, depending on the source of the water and how it has been treated. In some areas, the water supply may naturally contain high levels of sodium, particularly if the water comes from underground sources such as wells. Additionally, some water treatment processes, such as ion exchange or water softening, can increase the sodium content of drinking water.

It is worth noting that for most people, moderate sodium intake is not harmful to health, and in fact, our bodies need some sodium to function properly. However, excessive sodium intake can be a risk factor for high blood pressure and other health problems, particularly for people who are sensitive to sodium or who have certain underlying health conditions.

If you are concerned about the sodium content of your drinking water, you can have your water tested by a certified laboratory. Additionally, if you have concerns about your sodium intake, you may want to talk to your doctor or a registered dietitian for advice on how to manage your sodium intake.


Chlorine is often used to disinfect drinking water in order to kill harmful bacteria and viruses that can cause illness. For instance, chlorine is considered a highly effective disinfectant to help protect against waterborne diseases such as cholera, typhoid, and hepatitis A. But is it safe to drink water with chlorine? While chlorine can have a strong odor and taste, the levels typically used in drinking water are considered safe for human consumption. 

However, some people may be more sensitive to the flavor of chlorine in their drinking water, and there are also some concerns about the potential health effects of long-term exposure to low levels of chlorine and its byproducts. As a result, some people choose to use whole-home water filtration or other treatment methods to remove chlorine from their drinking water.


Arsenic can be present in drinking water, particularly in areas with high levels of naturally occurring arsenic in the soil or rock. Ingesting high levels of arsenic over a long period of time can lead to health problems such as skin lesions, cancer, and other health effects. Public water systems are required to test for arsenic and other contaminants and to treat water that exceeds the maximum allowable amount of arsenic.

However, if you have a private well, you may want to have your water tested for arsenic and other contaminants. It is important to note that boiling water does not remove arsenic and may actually increase its concentration. If you are concerned about the presence of arsenic in your drinking water, you should contact your local water utility or water filtration professionals for testing and advice on appropriate treatment options.


Lead can be present in drinking water, particularly in older homes and buildings with lead pipes or fixtures. Lead can leach into the water supply from the pipes, fittings, and solder used in plumbing systems. Exposure to lead over time can lead to a range of health effects, particularly for infants, young children, and pregnant women.

As with arsenic, public water systems are required to test and treat water for lead. However, lead can also be present in the plumbing systems of individual homes and buildings. Lead can be highly dangerous, so if you are worried about lead in your drinking water, seek testing and treatment advice from professionals near you.

How to Get Purer Water at Home

As it turns out, water can contain a lot more than just hydrogen and oxygen. But at The Science of Water, we understand that water safety is a critical priority to protect your health and your family. That’s why we offer free water testing and consultations to guarantee the safety of your home’s water supply.

At The Science of Water, we assess and install water filtration systems to meet your unique needs. Using filtration technology backed by NASA and the EPA, our advanced water systems purify your home’s tap water to the highest standard. Whatever you’re looking for in a water filtration system, we can help you enjoy safer, clearer, and more delicious water through every faucet and appliance in your home.

Don’t wait to find out about contamination when it’s already too late. Proactively protect your household with water testing and filtration for pure, delicious H2O that can be relied on. For more information about The Science of Water or to book your free water test, just get in touch with our team today!