Which drinking water is healthiest? The pros and cons of tap, bottled, filtered and more.

Over the past few months, clean water has come under the microscope thanks to a slew of research analyzing what’s in the stuff we drink. The latest is a study that has detected a previously unidentified chemical byproduct in drinking water.

The substance, called “chloronitramide anion,” is made when water is treated with chloramine. Chloramine is a chemical formed by mixing chlorine and ammonia, and it’s used to kill viruses and bacteria in municipal water treatment systems. It’s important to note that scientists have no clue at this point if chloronitramide anion is dangerous or harmless; they simply identified it.

But this latest finding joins plenty of other studies about what, exactly, is in drinking water, from concerns about excess levels of fluoride to the discovery of plastic particles (about 240,000 detectable fragments in one liter) in bottled water.

There’s a lot of information about drinking water to wade through, and all of it raises questions about how safe it is. So, what’s the healthiest way to drink water? Here's what clean water experts and environmental scientists say.

Is drinking water less safe than it used to be?

Not necessarily. “Advances in analytical chemistry have made it possible to detect a wider variety of chemicals in water at much lower levels,” Xindi Hu, assistant professor of environmental and occupational health at the George Washington University Milken Institute School of Public Health, tells Yahoo Life. “This shift has given us more data than we often know how to interpret.”

But water systems are also dealing with complications from natural and human-driven issues. “Climate change, for example, is altering the water cycle, potentially affecting the quantity and quality of source water,” Hu says. “Industrial emissions and evolving water treatment techniques also present challenges to maintaining safe drinking water.”

People are also paying attention to what’s in their drinking water more now than ever before, Gerald Kauffman Jr., director and associate professor at the University of Delaware Water Resources Center, tells Yahoo Life. “It’s a combination of greater awareness and having better ways to detect what’s in our water,” he says.

All of this doesn’t mean that water is less safe than it was before, though. “If anything it is more safe, as municipalities increase the biologicals and chemicals that are regularly being monitored,” Phoebe Stapleton, associate professor in the Department of Pharmacology and Toxicology at the Rutgers University Environmental and Occupational Health Sciences Institute, tells Yahoo Life.

What’s the healthiest way to drink water?

You have options when it comes to drinking water, and each has potential pros and cons. Here’s what experts want you to keep in mind for each.

Tap water

Tap water is the most cost-efficient way to get your water, and it’s subject to testing by your municipality, Stapleton points out.

The Safe Drinking Water Act, which was passed by Congress in 1974, regulates the country’s drinking water supply, focusing on waters that are or could be used for drinking. This act requires public water systems to follow standards set by the Environmental Protection Agency (EPA), which includes monitoring the water and reporting on findings. The act also requires water systems to issue annual water quality reports to customers.

“This protects the health of our drinking water supplies, and mostly just protects us,” Kauffman says.

While research has shown that tap water is the most likely to be contaminated compared to bottled and filtered water, Kauffman says he drinks tap water. “We have never had it so good,” he says. “By and large, the water in the U.S. is very safe.”

Filtered water

Filtering your water is an “extra level of assurance” that your water is safe, Kauffman says. But the type of filter you choose matters, John Rumpler, clean water director and senior attorney for Environment America, tells Yahoo Life. “If you’re concerned about lead or forever chemicals, you want to look for a filter that is independently certified to remove those toxic substances,” he says.

Some filters are just designed to remove odors and improve taste, Rumpler points out. “That isn’t going to do anything for toxic contaminants,” he says. “If you’re concerned about lead, you want a filter that removes lead.”

To get the most out of your filtered water, Rumpler says it’s important to learn more about your municipal water and water service lines to see what you need to filter out. Once your filter is installed, it’s also crucial to stay on top of maintenance, he says. “The filter is not going to work if you don’t install it correctly and replace it when it needs to be replaced,” he adds.

While Stapleton says that filtering your water can be a good choice, she notes that this can be costly to maintain.

Plastic bottled water

There are a few potential concerns with plastic water bottles. “One is the plastic bottle itself,” Rumpler says. “There is some evidence to suggest that microplastics are in plastic bottled water — that’s a problem.”

Plastic water bottles can also be costly and create waste, Stapleton says. Bottled water has been surrounded by a health halo, Hu adds. “Bottled water is not necessarily safer than tap water, and oftentimes [the quality is] similar to or worse than tap water,” she says. “This is because bottled water is regulated by the Food and Drug Administration — not the EPA — and is not subject to the same level of scrutiny as public water supplies.” While some bottled water is from a spring or filtration system, research shows that nearly 65% of bottled water sold in the U.S. comes from municipal tap water.

But Rumpler says there can be benefits to drinking plastic bottled water. “If you have a lead pipe in your home or a lead service line, it could be that bottled water is a less risky choice,” he says. (However, Rumpler adds that filters designed for lead are often the best choice when you're concerned about contamination.)

Glass bottled water

Glass bottled waters are less common in the U.S., but there are some brands that sell them. “Glass avoids the problems related to plastic bottles, such as being environmentally unsustainable,” Rumpler says. “It also avoids the risk of microplastics potentially leaching from plastic bottles.”

But glass bottled water tends to be significantly more expensive than its plastic bottle counterparts. These bottles are also fragile, making them less reliable than plastic options, Stapleton points out. As for the quality of the water, a lot depends on where the water is sourced — the same potential issue with plastic bottled water, Rumpler says.

Fridge dispenser water

Water that’s dispensed from the refrigerator is a lot like filtered water from your tap, Rumpler says. “You’ll want to read the owner’s manual to see if the refrigerator has a filter that’s certified to remove the contaminants you want,” Rumpler says. “But there’s nothing magical about water from the fridge. Don’t assume that it’s cleaner coming from the fridge versus the sink.”

As with filtering water from your tap, it’s also important to ensure your refrigerator water filter is installed correctly and replaced as needed.

The bottom line

While there are concerns about drinking water, experts stress that most Americans have access to clean water — and should be drinking it. “Despite occasional concerns, tap water in the U.S. is generally high-quality and safe to drink,” Hu says. “Water remains the healthiest choice for hydration.”