I want to tell you about the year I was absolutely, bone-deeply exhausted — and I had no idea why. It was a Tuesday morning in October, and I remember sitting at my kitchen table with my third cup of coffee, staring at the wall like someone had unplugged me from the wall socket. I was sleeping eight hours a night. I was eating well — mostly, anyway. I’d been doing my yoga, taking my magnesium, reading all the right things about morning routines. And yet I felt like I was living my life underwater. Foggy. Heavy. Like everything I did required twice the energy it should have. My doctor ran the usual panels. Nothing alarming. “Maybe stress,” she said. “Maybe seasonal.” I nodded and drove home feeling that particular kind of defeat that comes when something is clearly wrong but nobody can name it. What finally cracked it open? An offhand conversation with my neighbor, who’d just come back from visiting her sister in another state. Her sister had been dealing with the same thing — chronic fatigue, brain fog, weirdly persistent headaches — and a functional medicine practitioner had asked her one simple question: What does your tap water taste like? I know. It sounds almost laughably simple, doesn’t it? But I remember laughing a little nervously, walking to my kitchen sink, filling a glass, and actually paying attention to it for the first time in years. There was a faint metallic edge. Something slightly… off. I’d been drinking that water every single day. Multiple glasses. Cooking with it. Making my morning green tea with it. Within two weeks of switching to filtered water, I felt like someone had turned the lights back on in my brain.
The Connection Nobody Talks About Enough
Here’s the thing about water — we treat it like it’s neutral. Like it’s just there, a blank canvas that nothing can ruin. But your tap water travels a long, complicated journey before it hits your glass. It moves through aging infrastructure, picks up runoff from surrounding land, absorbs traces of whatever it brushes against along the way. Municipal water treatment does a genuinely important job, and I want to be clear: I’m not here to scare anyone. But treatment doesn’t remove everything. And some of what slips through? It has a very real impact on how you feel.
I’ve written a bit before about my own water-quality journey — the testing I did, the rabbit hole I fell down, the surprising things I found — and if you want the deeper backstory, that post is a good place to start. But today I want to talk specifically about the five contaminants that came up again and again in my research. The ones that are most commonly present in household water. The ones that can quietly, subtly, drain your vitality without you ever connecting the dots.
Let’s dig in.
1. Chlorine and Chloramine Byproducts
Chlorine is genuinely useful. Water treatment facilities use it to kill bacteria and pathogens, and without it, waterborne illness would be a much bigger problem than it is. So I want to give chlorine its due. But here’s the complicated part: when chlorine reacts with natural organic matter in water — things like decaying leaves, sediment, plant material — it forms compounds called disinfection byproducts, or DBPs.
The most studied of these are trihalomethanes (THMs) and haloacetic acids (HAAs). Long-term exposure to elevated levels has been associated with increased oxidative stress in the body — which is basically your cells working harder than they should to manage cellular damage. Think of oxidative stress like your body’s engine running slightly too hot, all the time. It’s one of the sneakiest energy drains there is, because there’s no single moment where you feel terrible. You just feel… less.
Many municipalities are now using chloramine (chlorine combined with ammonia) instead, which creates fewer THMs — but its own set of byproducts that researchers are still studying. The science is evolving. What we do know is that these compounds aren’t inert once they’re in your body.
2. Lead
This one gets headlines when it’s really bad — Flint, Michigan being the most heartbreaking example — but the quieter reality is that low-level lead exposure through tap water is more common than most people realize. Here’s why: the EPA’s regulations focus on water leaving the treatment facility, not water arriving at your tap. And a huge portion of American plumbing infrastructure — especially in homes built before 1986 — includes lead pipes, lead solder, or lead-containing fixtures.
Lead leaches into water as it sits in those pipes. And lead, even in small amounts, is a neurotoxin. It competes with calcium and iron in the body, disrupts neurotransmitter function, and has been directly linked to fatigue, difficulty concentrating, and mood disturbances in adults. Not just in children. In adults.
I had my water tested and found low but measurable lead levels. Low enough that nobody would flag it as an emergency. High enough that once I understood what lead does in the body at a cellular level, I didn’t want any of it in my morning glass.
3. Nitrates
Nitrates mostly enter water supplies through agricultural runoff — fertilizers, animal waste, that kind of thing. If you live in a rural area or near farming land, your risk of elevated nitrate levels is higher, but urban wells and municipal systems aren’t immune either.
At high levels, nitrates are acutely dangerous, especially for infants. But at lower, chronic levels — the kind that slip under regulatory thresholds — nitrates interfere with your blood’s ability to carry oxygen efficiently. That process is called methemoglobinemia at its clinical extreme, but the subclinical version is basically: your red blood cells are slightly less effective at doing their job. Less oxygen delivery to your tissues and brain. Less energy. More brain fog. More of that “wading through mud” feeling I knew so well.
When I explain this to people, they often say, “But my water tests fine legally.” And I get that. But the legal limits are set based on acute toxicity thresholds, not on the subtler, cumulative effects of long-term low-level exposure. There’s a difference.
4. Pharmaceutical Residues and Endocrine Disruptors
Okay, this one still kind of blows my mind a little.
Wastewater treatment plants are incredibly sophisticated, but they weren’t originally designed to filter out pharmaceuticals. When people take medications — hormones, antidepressants, antibiotics, painkillers — some of those compounds pass through the body and enter the sewage system. Treatment removes a lot of it. Not all of it.
Studies have found trace levels of hormones (including estrogen-like compounds), antidepressants, and antibiotics in treated drinking water across the country. These are genuinely tiny concentrations — we’re talking parts per trillion in most cases. The research on what that means for human health long-term is still developing, and I want to be honest about that uncertainty.
But endocrine disruptors — compounds that mimic or interfere with your hormonal signals — are uniquely concerning because hormones operate at incredibly small concentrations naturally. The thyroid, for example, functions on nanogram-level hormone signals. Compounds that disrupt that system don’t need to be present in massive amounts to have an effect. Fatigue, weight changes, mood shifts, sleep disruption — these are all classic symptoms of subtle hormonal disruption.
Your water might be a piece of that puzzle.
5. Heavy Metals: Arsenic, Mercury, and Copper
Beyond lead, there’s a whole cast of heavy metal characters that can show up in tap water depending on where you live and how old your plumbing is.
Arsenic occurs naturally in some groundwater sources — particularly in parts of the western US and New England — and has been linked to mitochondrial dysfunction, which is basically a fancy way of saying it messes with your cells’ ability to produce energy. At the mitochondrial level. The foundational energy level.
Copper can leach from copper pipes, especially in slightly acidic water, and while your body needs trace copper, excess copper competes with zinc and can create neurotransmitter imbalances — affecting mood, focus, and yes, energy.
Mercury is less common in municipal water but can show up in areas near certain industrial sites or through contaminated groundwater. It bioaccumulates and is a particularly potent neurological disruptor.
None of these are guaranteed to be in your water. But “I probably don’t have this problem” is a very different thing from “I know I don’t have this problem.” The test is the thing.
So What Can You Actually Do?
Okay. Deep breath. I don’t want this to feel overwhelming — I really don’t. Because the truth is, there are genuinely accessible things you can do, and it doesn’t have to cost a fortune.
Start with a water test. This is the most important step and the one most people skip. You can order mail-in testing kits online for anywhere from $20 to $150 depending on how comprehensive you want to be. The EPA also has resources to help you find certified local labs. Know what’s actually in your water before you invest in any solution. It changes everything.
Get a quality filter — and match it to your results. Not all filters do the same thing. A basic activated carbon filter (like a Brita) is great for chlorine taste and some organic compounds, but it won’t touch lead or nitrates. Reverse osmosis systems are much more comprehensive — they filter out a very wide range of contaminants, including heavy metals, nitrates, and many pharmaceuticals. Countertop RO systems have gotten much more affordable in recent years. If a whole-house or under-sink system isn’t in the budget right now, even a high-quality pitcher filter certified by NSF International for multiple contaminant categories is a meaningful step.
Let your tap run before you drink. Especially if your pipes are older or you haven’t used the tap for a few hours. Water that’s been sitting in lead or copper pipes has had time to absorb more of those metals. Running the tap for 30 seconds to two minutes before drinking or cooking can meaningfully reduce your exposure.
Advocate at the community level. Individual filters are important, but they’re also a bandage. The real fix is updated infrastructure, stricter regulatory standards, and community pressure on local water utilities to be transparent about what’s in the water and what they’re doing about it. You can request your local water quality report (called a Consumer Confidence Report) — utilities are required to provide them annually. Read it. Ask questions. Show up to city council meetings if this matters to you. It matters.
Stay hydrated — with the right water. I know this sounds obvious, but one of the sneaky side effects of water that tastes bad or makes you feel off is that you drink less of it. And dehydration alone — even mild dehydration — causes fatigue, headaches, reduced concentration, and mood dips. Once I started filtering my water and actually enjoying drinking it, my hydration went up, and that made its own positive difference.
Clean Water Changed Everything For Me
I’m not exaggerating when I say that improving my water quality was one of the most impactful wellness changes I’ve ever made. More impactful, honestly, than any supplement I’ve tried. It was foundational in a way I hadn’t expected, because I hadn’t been paying attention to the foundation at all.
Your body is somewhere between 55% and 75% water, depending on who you ask and how you’re measuring. You replace a significant portion of it every single day. What that water carries into your cells — or doesn’t carry — genuinely matters. It’s not woo. It’s not fear-mongering. It’s just basic biochemistry.
If you’re doing all the right things and still feeling tired, foggy, or off — please, before you chalk it up to stress or getting older or just being someone who needs more sleep, ask yourself: What’s in my water?
It might be the most powerful question you ask this year.
Have you ever tested your tap water or made a switch to filtered water? I’d love to hear your experience in the comments below. And if you’re just starting to look into this, be gentle with yourself — this is a journey, not a quiz. You’re already asking the right questions just by being here.
Sending you so much good energy,
— Rachel
Positively-you.com | Wellness that actually fits your real life