Lithium is a naturally occurring metal increasingly found in American drinking water supplies, yet many people have never heard of it as a contaminant. Unlike lead or arsenic, lithium doesn't have a federal drinking water standard, which means tap water supplies aren't regularly tested for it and there's no legal limit on how much can be present. This regulatory gap has raised concerns among scientists and public health officials, particularly in states like Texas, California, and other regions where lithium naturally occurs in groundwater or where wastewater from pharmaceutical manufacturing enters water sources. If you're concerned about what's in your tap water, understanding lithium's sources, health effects, and removal options is an important first step toward protecting your family.
What Is Lithium and Where Does It Come From
Lithium is a soft, lightweight metal that occurs naturally in soil and rock formations. It dissolves easily in water, which means it can leach into groundwater supplies over time. In drinking water, lithium exists as an ion (a charged particle) that can travel freely through water systems.
There are three main sources of lithium in American drinking water:
Natural Geological Deposits
The most common source of lithium in drinking water is natural occurrence in rock and mineral formations. Groundwater that passes through limestone, shale, and other sedimentary rocks picks up lithium naturally. This is especially common in the southwestern United States, where arid climates and certain geological formations concentrate lithium in water supplies. States like Texas, California, Nevada, and New Mexico have documented higher lithium levels in some municipal water systems due to these natural deposits.
Pharmaceutical Wastewater
Lithium carbonate and lithium citrate are widely prescribed medications for bipolar disorder and other mental health conditions. When people take these medications, some lithium passes through their bodies and enters wastewater. While wastewater treatment plants remove many contaminants, lithium is highly soluble and not effectively filtered out by standard treatment processes. As a result, treated wastewater discharged into rivers and streams can add lithium to water sources downstream.
Industrial and Mining Operations
Lithium mining and industrial production create waste streams that can contaminate groundwater. Additionally, some industrial cooling systems and manufacturing processes use lithium compounds, releasing them into the environment. Although less common than natural sources, industrial contamination can cause localized spikes in lithium levels near manufacturing facilities.
Current EPA Guidance and Regulatory Status
Unlike lead, which has a federal maximum contaminant level (MCL) of 15 parts per billion (ppb), lithium has no EPA drinking water standard. This means water utilities are not required to test for lithium or remove it from public water supplies. However, this doesn't mean the EPA has declared lithium safe.
In 2020, the EPA added lithium to its Candidate Contaminant List (CCL), a roster of substances that may warrant future federal drinking water regulations. The EPA collects occurrence data and reviews health effects studies to determine whether a contaminant poses enough of a public health threat to justify a national standard. The fact that lithium made the CCL reflects growing scientific concern about its presence in U.S. water supplies.
The EPA has established a reference dose (RfD) of 0.2 milligrams per kilogram of body weight per day based on animal studies. While this is not a drinking water standard, it gives scientists a benchmark for assessing safe exposure levels. Some water utilities and health agencies have suggested informal guidance levels ranging from 40 to 400 parts per billion, though these vary widely and are not federally mandated.
Health Effects of Lithium in Drinking Water
Lithium's most well-documented health effect involves thyroid function. Because lithium is chemically similar to sodium, the body can absorb it and it can interfere with iodine metabolism, which is essential for thyroid hormone production.
Thyroid and Metabolic Effects
Several peer-reviewed studies have found associations between elevated lithium in drinking water and increased rates of hypothyroidism, a condition in which the thyroid doesn't produce enough hormone. A 2013 study published in the American Journal of Epidemiology examined thyroid disease rates across different water districts and found that areas with higher lithium levels in drinking water had higher rates of hypothyroidism diagnoses. While these are observational studies and don't prove causation, they raise legitimate concern, especially for people who are already at risk for thyroid problems.
Neurological and Developmental Concerns
Lithium is used therapeutically in psychiatric medications because it affects brain chemistry. Some research has explored whether chronic, low-level exposure to lithium in drinking water might affect neurological development in children or cognitive function in adults. Studies in this area are still emerging, but animal research suggests that lithium exposure during critical developmental windows could have subtle effects on learning and behavior. Pregnant women and young children are generally considered more vulnerable populations for this reason.
Vulnerable Populations
Certain groups face higher risk from lithium exposure. These include people with pre-existing thyroid conditions, pregnant women, nursing mothers, infants fed formula made with tap water, individuals taking lithium medications for bipolar disorder, and people with kidney disease. If you fall into any of these categories, discussing your tap water with your doctor is a sensible precaution.
Which States and Communities Have Detected Lithium
Lithium has been detected in drinking water supplies across the United States, but some regions show higher concentrations:
- Texas has documented lithium in multiple water systems, particularly in the Panhandle and South Texas regions where natural geological deposits are common
- California has found lithium in parts of Southern California and the Central Valley, linked to both natural sources and wastewater discharge
- Nevada and Utah show elevated levels in certain groundwater-fed systems due to natural mineral deposits
- Oklahoma and New Mexico have also reported detectable lithium in some municipal supplies
- Arizona has found lithium in groundwater, particularly in agricultural areas
Eastern and midwestern states generally report lower lithium levels, though some detection has occurred near pharmaceutical manufacturing facilities or in areas with specific geological conditions. The variation is significant, which is why knowing what's in your specific tap water matters. You can check your local water quality using ClearWater's free ZIP code lookup tool at checkclearwater.com to see if lithium has been detected in your area.
How to Test Your Tap Water for Lithium
Because lithium testing isn't part of routine EPA oversight, you'll need to take initiative if you want to know your exposure level.
Get Your Water Quality Report
Every municipal water utility is required to publish an annual Consumer Confidence Report (CCR) that lists all contaminants detected in the water supply. However, most utilities only test for federally regulated contaminants, which doesn't include lithium. You can request a copy of your water utility's CCR by visiting their website or calling their office directly. This report won't tell you about lithium, but it will give you a complete picture of what else is in your water.
Use Free Online Lookup Tools
ClearWater provides a free, EPA-backed lookup tool where you enter your ZIP code and see reported lithium detections and other contaminants. This tool aggregates public data from EPA databases and can quickly show you whether lithium is a concern in your community.
Get Professional Water Testing
For the most accurate picture, you can hire a certified water testing laboratory to analyze a sample from your tap. They can test specifically for lithium as well as other unregulated contaminants. Expect to pay $100 to $300 for comprehensive testing that includes lithium. Your local health department can recommend certified labs in your area.
Methods to Remove Lithium From Drinking Water
If you've discovered that lithium is present in your tap water and you want to reduce your exposure, several effective treatment methods are available.
Reverse Osmosis Systems
Reverse osmosis (RO) is one of the most effective methods for removing lithium from drinking water. In an RO system, water is forced through a semipermeable membrane that filters out dissolved minerals and ions, including lithium. Most lithium ions are effectively removed by RO systems, typically reducing lithium concentration by 90 to 98 percent. These systems can be installed under the sink as point-of-use filters (serving just your drinking water) or as whole-home systems. The main drawback is that RO systems produce wastewater and remove beneficial minerals along with contaminants, though many people add a remineralization filter to address this.
Ion Exchange Resin Systems
Ion exchange systems use special resin beads that swap ions. An ion exchange water softener designed to remove lithium can be effective, though standard water softeners may not be optimized for lithium removal. These systems work by passing water through charged resin beads that capture lithium ions and release less harmful ions in their place. Ion exchange is particularly useful for whole-home treatment and can also remove other ions like calcium and magnesium. These systems require periodic regeneration with salt or potassium chloride.
Activated Carbon Filters
Standard activated carbon filters are not effective for removing lithium, since lithium ions aren't attracted to carbon in the same way that organic contaminants are. However, carbon filters are excellent for removing chlorine, some pesticides, and improving taste and odor, so they're often used alongside other treatment methods.
Distillation
Distillation systems boil water and collect the steam, leaving contaminants like lithium behind. Distilled water is essentially free of all dissolved minerals and ions. The drawback is that distillation is slow and energy-intensive, making it impractical for whole-home use. Some people use distillers for drinking and cooking water only.
Whole-Home vs. Point-of-Use Treatment
For most households, point-of-use systems like under-sink reverse osmosis filters provide a cost-effective solution for drinking and cooking water. Whole-home systems are more expensive but treat all water entering the house, which some people prefer for bathing and showering. Your choice depends on your budget, your household's water usage, and how concerned you are about total lithium exposure.
Steps You Can Take Today
If you're concerned about lithium in your tap water, here's a practical action plan:
- Check your water quality baseline. Use ClearWater's free ZIP code lookup tool to see if lithium has been detected in your area. This takes two minutes and gives you a clear answer about whether it's a concern for you.
- Request your water utility's Consumer Confidence Report. Call your local water department and ask for their latest annual report, which lists all detected contaminants and their levels.
- Assess your risk level. If you're in a vulnerable population (pregnant, thyroid issues, caring for an infant, or living in a high-lithium area), consider getting professional water testing to know your actual exposure.
- Talk to your doctor. If you're on lithium medication or have thyroid concerns, discuss your tap water quality with your healthcare provider. They can help you assess whether treatment is necessary for your situation.
- Explore treatment options. If testing confirms elevated lithium, research reverse osmosis systems or ion exchange filters that fit your budget and space. Start with point-of-use systems if whole-home treatment is too costly.
- Stay informed about regulations. The EPA continues to gather data on lithium. Following updates on the Candidate Contaminant List can help you understand whether federal standards might be coming.
The Bottom Line on Lithium in Drinking Water
Lithium is an unregulated contaminant increasingly detected in U.S. drinking water, with the highest concentrations found in the Southwest and areas affected by pharmaceutical wastewater. While the EPA hasn't set a mandatory limit, the scientific evidence linking lithium to thyroid effects and potential neurological impacts is strong enough that the substance made the Candidate Contaminant List. This suggests federal action may be on the horizon.
For now, the responsibility falls on individual households to assess their risk and take action if needed. By checking your local water quality, understanding your exposure, and knowing that effective removal methods like reverse osmosis exist, you can make informed decisions about your family's water safety. If you live in an area with documented lithium or if you're in a vulnerable population, taking the time to test your water and explore treatment options is a worthwhile investment in your long-term health.