Tap water originates from surface water sources such as lakes, rivers, and reservoirs or from groundwater stored in aquifers and wells. Once collected, it undergoes treatment at municipal plants before being distributed through an extensive network of pipes. While the treatment process removes many contaminants, the journey of water doesn’t end at the treatment facility. As it travels through aging infrastructure—some of which is over a century old—it can pick up additional contaminants along the way.
A crucial but often overlooked factor is that water doesn’t just move through pipes; it interacts with them. Older lead pipes or corroded infrastructure can introduce harmful substances into otherwise clean water. Even within your home, the type of plumbing you have—whether PVC, copper, or aging lead—can affect water quality. If you’re considering upgrading your plumbing to ensure cleaner water, consulting a professional plumber can help you choose the best materials for your home’s water system.
Surprisingly, water in some cities undergoes “blending,” meaning different sources are mixed to manage shortages. As a result, your water’s composition can change daily, depending on where it’s sourced. This means the water flowing from your tap today might be quite different from what comes out tomorrow.
The Hidden Contaminants Lurking in Your Water
Many people assume their tap water is safe simply because it meets regulatory standards. However, even legally “safe” water can contain trace amounts of contaminants that accumulate in the body over time. These contaminants range from heavy metals like lead, arsenic, and mercury to disinfection byproducts such as trihalomethanes, which form when chlorine interacts with organic matter. Pharmaceuticals, including birth control hormones and antidepressants, have also been found in tap water, as traditional treatment plants aren’t designed to remove them entirely.
Some lesser-known threats include microplastics, which are found in 94% of U.S. tap water, and perchlorate, a component of rocket fuel, which contaminates some water supplies near military bases. Hexavalent chromium, a cancer-causing chemical made famous by Erin Brockovich, is present in the water of two-thirds of Americans. Algal toxins, which result from increasing algal blooms due to climate change, can also slip into drinking water and pose serious health risks.
One unexpected source of contamination comes from the improper disposal of human remains. Flushing cremated remains can introduce heavy metals like mercury into the water cycle, contributing to long-term pollution.
How Pollutants End Up in Your Drinking Water
There are several ways contaminants infiltrate water sources. Aging infrastructure plays a significant role, as rust, lead, and other materials from deteriorating pipes can leach into the water supply. Agricultural and industrial runoff introduce pesticides, fertilizers, and chemicals into lakes and rivers. Improper disposal of household products, including medications and cleaning agents, further pollutes wastewater. Additionally, natural sources such as heavy metals and radioactive elements can dissolve from rocks into groundwater.
One particularly concerning source of pollution is per- and polyfluoroalkyl substances (PFAS), commonly referred to as “forever chemicals.” Found in nonstick cookware, waterproof clothing, and fast-food wrappers, these chemicals do not break down in the environment and persist in water supplies indefinitely. Another surprising source is human excretion—pharmaceuticals pass through our bodies and enter the water cycle, where treatment plants fail to remove them effectively.
Why Water Treatment Plants Aren’t a Perfect Solution
Municipal water treatment plants are designed to meet legal safety standards, but that doesn’t mean they eliminate all contaminants. While they effectively remove bacteria, viruses, and large particles, they struggle with modern pollutants like PFAS, pharmaceuticals, and microplastics. The biggest misconception is that water meeting EPA standards is “pure.” In reality, it simply means contaminant levels fall within legally acceptable limits—not necessarily what’s ideal for long-term health.
Most treatment facilities still use filtration technology from the 1950s, which was developed to tackle problems of that era. However, today’s water contains new pollutants—synthetic chemicals, industrial waste, and microscopic plastics—that these systems weren’t designed to handle.
Simple Ways to Test Your Tap Water at Home
The only way to truly know what’s in your tap water is to test it. Homeowners have several options, ranging from basic DIY test kits to comprehensive lab analyses. DIY kits can detect pH levels, chlorine, and some heavy metals, but they lack the sensitivity to identify more harmful contaminants like PFAS and pharmaceuticals. Professional lab testing provides a more detailed breakdown, analyzing water for heavy metals, bacteria, and synthetic chemicals.
For a general overview, water suppliers provide annual Consumer Confidence Reports (CCRs), which outline detected contaminants. However, these reports don’t account for pollutants that enter your water after it leaves the treatment plant. To get an accurate picture, it’s best to test water from multiple points in your home, such as the kitchen sink and bathroom tap, as plumbing materials can impact quality.
The Health Risks of Unfiltered Tap Water
Even if your tap water is deemed safe by regulatory agencies, long-term exposure to low levels of contaminants can still pose health risks. Heavy metals like lead and mercury have been linked to neurological issues, especially in children. PFAS and pharmaceutical residues can disrupt hormones, while arsenic and disinfection byproducts are associated with an increased cancer risk. Additionally, chlorine-treated water can disrupt the gut microbiome, potentially leading to digestive issues and weakened immunity.
Some cities’ water supplies have chlorine concentrations higher than those found in swimming pools. While this helps control bacteria, prolonged exposure to chlorinated water can contribute to skin irritation and respiratory issues.
Do Water Filters Actually Work?
Not all water filters are equally effective, and it’s important to choose the right one based on your specific concerns. Activated carbon filters, like those in common pitcher systems, improve taste and reduce chlorine but don’t remove heavy metals or pharmaceuticals. Reverse osmosis (RO) systems are among the most effective, eliminating over 90% of contaminants, including PFAS and heavy metals. However, RO systems waste some water in the process. Distillation removes most impurities but is slow and energy-intensive, while ion exchange is useful for softening hard water but not for filtering toxins.
The best approach is a multi-stage filtration system combining activated carbon with reverse osmosis. It’s also crucial to replace filters regularly, as an expired filter can become a breeding ground for bacteria.
Tap Water vs. Bottled Water: Which Is Safer?
Bottled water isn’t necessarily cleaner than tap water. Over 60% of bottled water is sourced from municipal supplies, meaning it’s essentially filtered tap water. Unlike municipal water, which undergoes frequent testing, bottled water is often tested less rigorously—sometimes only once a year. Additionally, plastic bottles can leach chemicals and microplastics into the water, further compromising quality.
Instead of relying on bottled water, investing in a high-quality home filtration system can provide safer, more cost-effective drinking water in the long run.
The Biggest Myths About Tap Water, Debunked
A common misconception is that if tap water looks clear and has no smell, it must be safe. However, many harmful contaminants, such as lead and PFAS, are completely invisible. Some people assume that bottled water is inherently safer, but in many cases, it’s just repackaged tap water with fewer regulations. Others believe that boiling water removes all contaminants—while it kills bacteria, it does nothing to eliminate heavy metals or synthetic chemicals.
Take Control of Your Water Quality Today
Water quality isn’t just about what leaves the treatment plant—it’s about what reaches your tap. With aging infrastructure and increasing pollutants, testing your water and choosing the right filtration system is essential for long-term health. If you’re mindful of the food you eat, you should be just as careful about the water you drink every day.
