Your tap water has been through a lot more than you’d think...

It first comes from a river, a lake, or a well drilled deep underground. From there, it flows to a treatment plant and then through the country's water pipes. That network of pipes stretches more than 2 million miles, which is enough to circle Earth 80 times. Finally, that water winds through the plumbing in your walls, all before it reaches your faucet—let alone your glass.

At every stop along the way, your water can be exposed to new dangers and accumulate contaminants… 

That’s why we mapped out tap water’s journey from source to sip, to show you where it goes and what can happen by the time water flows from your faucet. 

• Tap water makes several stops on its way from its source to you. Contamination can accumulate along the way.
• Before it's treated, water from rivers, lakes, and underground aquifers can be exposed to contaminants by the land around it and the rock beneath it.
• Treatment plants aren’t required to target unregulated dangers, and the disinfection process itself can lead to the formation of new dangers.
• After treatment, water mains, service lines, home plumbing, and faucets can expose treated water to additional risks. 
• Clearly Filtered's Filtered Water Pitcher protects you from up to 386+ common contaminants, including lead, PFAS, lithium, and nitrate.

Before water is treated at your local utility, it needs to come from somewhere. In other words, it must be sourced… 

Most of the water utilities treat comes from surface water, such as rivers, lakes, and reservoirs. The rest is groundwater, which collects underground in natural layers of sand, gravel, and rock called aquifers. Utilities drill wells down into those aquifers to bring the water up.

Before it even reaches the treatment plant, water from both sources can be contaminated... 

Surface water, for example, collects what's on the ground around it, as pesticides, fertilizer, and other dangers wash off nearby farm fields, lawns, and streets into these rivers and lakes.

Groundwater, on the other hand, can collect what's in the ground. For example, arsenic, a known carcinogen, and radioactive radium occur naturally in the rock around aquifers and slowly dissolve into the water. Meanwhile, chemicals from farms and factories can seep down into groundwater from above. That includes nitrate from fertilizer—which the EPA warns can make babies seriously ill—as well as PCE, a dry-cleaning and degreasing chemical linked to cancer and liver problems.

Of course, treatment plants exist to ensure our water meets federal safety standards before it flows from your utility to your tap… 

324 contaminants have been detected in U.S. tap water, and yet the EPA has established legal limits for only about 90 of them.

While treatment plants are required to target those 90 or so regulated dangers, hundreds of other unregulated dangers can remain in your water—even after treatment… 

For example, microplastics have no enforceable legal limit. The same is true for lithium, manganese, and dozens of other dangers found in our tap water supplies.  

Many Regulated Contaminants Are Legally Allowed In Your Water At Controversial Levels

Legal isn't the same as safe…  

For every regulated contaminant, the EPA sets two numbers: One is a health goal, which is the level at which no harm is expected. The other is the legal limit, which set as close to that health goal as is “feasible.” 

The EPA defines feasible as what can be achieved with the best available technology, taking cost into consideration… 

Arsenic is just one example where the contaminant’s legal limit is well above the EPA’s health goal. Because it's a known carcinogen, the health goal for arsenic is zero. However, its legal limit is 10 parts per billion. In other words, 10 ppb of arsenic is legally allowed in our drinking water today. 

Benzene, a cancer-linked chemical that can leak from gas storage tanks, and PCE are in a similar boat. Both contaminants have a health goal of zero, and both are legally allowed in your tap water at up to 5 ppb.

Sometimes, Treated Water Doesn't Meet Federal Health Standards

Even the EPA acknowledges this happens…

The agency reported that in 2022, almost 3,000 community water systems had a health-based violation. 

That means about 22 million Americans, more people than live in New York State, drank water that failed to meet at least one federal health standard. 

The Treatment Process Can Unintentionally Create New Contaminants, Too

Most utilities disinfect with chlorine. It's a cheap and reliable way to kill bacteria and viruses in tap water… 

But chlorine works a lot like a hot grill: The heat that kills bacteria in a burger also creates new chemicals where the meat chars. Chlorine kills germs in your water, but it can also react with organic matter in the water that treatment didn’t fully remove (like decayed leaves, plants, and soil). 

When that happens, new chemicals known as disinfection byproducts (DBPs) can form. 

Scientists have identified more than 600 DBPs, and yet the EPA sets legal limits for only a fraction of them. Worse, two of the most common groups of DBPs, trihalomethanes (THMs) and haloacetic acids (HAAs), have both been linked to an increased risk of cancer. 

Once water leaves the treatment plant, it flows into water mains. Mains are the large pipes buried under your street that carry water through entire neighborhoods. Unfortunately, those mains break constantly… 

According to the American Society of Civil Engineers (ASCE), breaks occur about 240,000 times a year, or roughly once every two minutes.

A break drains the pressure in the pipes. That pressure is what pushes water out of your tap. It also keeps dirt, bacteria, and everything else outside the pipes from getting in. Without pressure, every crack and loose joint becomes a way in. When pressure is lacking, dirt, groundwater, and bacteria can get pulled into the pipes and carried toward your tap.

Nearly every water system is at risk. After all, the EPA warns that cracks, breaks, and joints are common in water systems… 

When one of those weak spots gives way, a single break can put an entire city on a boil-water notice. For instance, in July 2026, one main break in Crowley, Texas, dropped the pressure across town, and state regulators ordered a boil notice for everyone on city water, nearly 8,000 households in all.

To reach your house, water branches off the main into a service line, a much smaller pipe, usually about an inch wide, that runs underground from the street to a single home. The EPA estimates that about 4 million lead service lines are still in use…

Over time, lead pipes naturally corrode, and as they do, lead can dissolve or flake off into the water flowing through the pipe. 

Remember, lead is a toxic metal that can damage the brain and nervous system. Even low levels of lead exposure have been linked to lower IQ in children. Utilities use chemicals to slow the corrosion, but as long as lead pipe touches the water, some risk remains.

Galvanized steel service lines carry a lead risk too. Galvanized steel lines can capture lead from a lead pipe upstream, then release it into the water years later. 

Once the service line reaches into your home, water moves into your plumbing: the pipes running through your walls and floors. Copper pipes and fittings are widely used in household plumbing, and here corrosion can strike again. In fact, corrosion is a major source of copper in drinking water… 

Excess exposure to copper can upset your stomach in the short term, and damage your liver or kidneys over time.

Older homes carry a lead risk as well. Until a 1986 federal ban, plumbers often joined copper pipes with lead solder. That means homes built before then are more likely to have lead solder. 

Now your plumbing is one thing, but what about the faucets your water flows from?

Most faucets are made of brass, a blend of copper and zinc. Like copper pipes, brass slowly corrodes, and the water flowing through it can pick up the copper it’s made of. And in some cases, that brass could contain lead, too. 

Until 2014, brass plumbing could legally be sold as "lead-free" and still contain up to 8% lead… 

And even the aerator, the small mesh screen at the tip of many faucets, can catch tiny bits of metal that corrode from your pipes, including lead. Over time, those particles can build up and contaminate the water flowing past them.

Take a sip and your water heads to your stomach and then your small intestine, which absorbs about 90% of it into your bloodstream… 

There, those contaminants can affect your health in several ways… 

Arsenic and DBPs have been linked to cancer, lead can damage a child's developing brain, copper can harm your liver and kidneys over time, and the list goes on… 

You don't get to choose your city's water source, repair the mains under your street, or swap out the service line in your yard overnight. But you do have the choice to filter your water…

Sadly, ordinary filters target as few as 5 of the 324 contaminants detected in U.S. tap water, letting dangers like lithium, nitrate, and PFAS pass right through.

Clearly Filtered, on the other hand, goes further for your health and safety… 

Powered by our advanced Affinity® Filtration Technology, our Filtered Water Pitcher protects you from up to 386+ common dangers, including lithium, nitrate, and PFAS. Plus, it's the only filtration technology that does so without removing healthy minerals from your water.

Enter your zip code here for a free, personalized report on the contaminants detected in your local water supply.