7 Water Toxins with Devastating Impacts to Human Health 

And how water management practices and technologies keep them at bay.

Google “dangerous tap water chemicals” and you’ll see an endless list of sensationalist articles. And fair enough. When left unchecked, toxins and pollutants in drinking water can have devastating impacts on human health. 

The good news? Your tap water is carefully treated to keep harmful toxins out of your glass. In fact, the United States and Canada enjoy some of the cleanest and safest drinking water in the world.

But there are still some risks you need to be aware of. Ongoing problems like lead pipes remain a concern in some cities, and new, emerging challenges like PFAS are starting to pop up. 

And what you may not realize is that you have a role to play in keeping the water safe.

So what can you do about it?

Here are seven of the most common water toxins and pollutants, how your water provider protects against them, and how you can help keep freshwater fresh. 


You’ve heard or read about PFAS. But is it something you should be concerned about? Well, yes—on a few levels. PFAS stands for poly- and perfluoroalkyl substances. And what you might not realize is that they are used to make everyday items in your home water and heat resistant (takeout packaging, nonstick pans, and food containers are just a few examples). 

So, why should you be concerned? PFAS are often referred to as “forever chemicals”. Meaning that they cannot naturally break down. That means a growing amount of PFAS are making their way into water sources. Health consequences could include cancer, organ failure, and hormonal changes—but research is ongoing. 

Water providers have a variety of techniques to remove PFAS from drinking water. Because this is a relatively new problem for water providers however, these technologies are only starting to be adopted.

If that worries you, there are some actions you can take. Ask your water provider for data on PFAS testing from your area. Avoid Teflon and nonstick pots and pans. Opt for household cleaners that don’t contain PTFE in the ingredients. And if you’re still concerned about PFAS in your home, consider installing a reverse osmosis filtration unit in your home. But be prepared to pay. These units can get expensive.


Lead is extremely toxic and dangerous to human health, even in low quantities. It usually enters fresh water sources via old, corroded lead pipes. Sadly, this is a known problem in some communities—we’ve all heard of the devastating Flint water crisis. Cities at risk of lead contamination are working quickly to identify and eliminate this aging infrastructure, and for good reason: memory loss, lack of concentration, muscle aches, depression, and body aches and pains are just some of the symptoms of lead poisoning.

Unlike removing mercury or microorganisms from fresh water supplies, locating dangerous lead piping is a complicated process. Cities like Toledo, Ohio have introduced smart technologies to pinpoint problematic pipes.This type of technology could help water management providers prevent future lead-based water crises from ever occurring again. 

If you’re concerned about lead in your water, check with your local water provider, municipality, or a plumber about the status of your pipes. When in doubt, opt for a filtration unit. Simple absorption or (you guessed it) reverse osmosis units will both do the trick. 


This is a bit of a mixed bag. On one hand, excessive chlorine exposure can cause skin and eye irritation. However, chlorine is a “miracle chemical” when it comes to keeping freshwater supplies safe and drinkable. Your tap water contains small levels of chlorine, and that’s critical for filtering out harmful microorganisms.

If you notice your water has a strong chlorine smell, a charcoal filter (like a Brita) can go a long way to neutralizing the taste.


Mercury is naturally occurring, and usually appears in non harmful concentrations. However, excess mercury levels from industrial pollution can be extremely harmful. Long term health problems include tremors, decreased mental function, and—in extreme cases—respiratory failure and death. 

Thankfully, water providers are very effective at preventing mercury from reaching unsafe levels. So while the health effects of mercury are alarming, it’s unlikely to put your household at risk. 

If mercury does concern you, for example, if you’re on well water rather than a municipal water supply, a reverse osmosis or absorption filtration can easily remove 95-97% of mercury from your water.


Did you know that flushing your unused medication down the toilet can be harmful to your community’s waterways? Trust us—those disposal instructions on your medications are there for a very good reason. 

Hospitals and care facilities dispose of an average of 250 million tons of unused medication a year. Can you imagine the impact on your health if that made it into your tap water? 

Water pollution from unused medications is usually from medical or manufacturing facilities not following the rules. But chucking a few of your unused pills in the garbage or toilet also adds to the problem. So, the next time you’re emptying out the medicine cabinet, follow those instructions.


Love a lawn that looks its greenest? Then you’ve probably used herbicides. Used to kill unwanted plants (weeds, mostly), herbicides can quickly spread to freshwater sources. Farms and golf courses are the primary culprits of herbicide introduction into water sources, but the herbicides you use to keep your lawn looking fresh also contribute. 

Seem harmless? It isn’t. Potential long-term impacts include organ damage (the liver, in particular), hormonal imbalances in children, and cancer. 

The good news is that filtration techniques like activated carbon, clay, and peat can all minimize the risks of herbicides, and your water is treated to remove these toxins before it even reaches your tap. Still, when it comes to personal lawn care and gardening, use best practices to prevent unwanted herbicides from entering your community’s water.


Similar to herbicides, pesticides are used to kill unwanted insects and bacteria in agriculture and lawn care. Pesticides can spread to fresh water sources much like herbicides—generally through rainfall and irrigation runoff. Like herbicides, there are a massive number of pesticides out there—and we don’t yet know the long-term health impacts of all of them. However, municipalities and water networks have effective ways to minimize their impacts.

There are a wide range of toxins and pollutants that can have harmful impacts on human health. But generally, the techniques your municipality uses to keep those risks at bay are very effective. 

Still, there are small actions we can all take to reduce exposure to potential pollutants, and to help ease the load on your water community’s water provider. 

When in doubt, make responsible choices, invest in a high quality water filtration service, and do your part to reduce the introduction of further toxins and pollutants into something so fundamental and critical to all of us—fresh water. 


Klir is the all-in-one water regulation and compliance platform built by water experts, for water experts. See how Klir works, and how we can help your utility save time and money—all while keeping your water safer and more secure.