What is Lithium* and Why Does It Matter?

Lithium in Tap Water: What You Need to Know

Lithium is a naturally occurring metal found in rocks, soil, and groundwater. It enters drinking water supplies primarily through geological leaching — meaning water picks it up as it moves through mineral-rich rock formations underground. Mining operations, industrial discharge, and even some pharmaceutical manufacturing can add lithium to surface water as well. Unlike many contaminants, lithium in tap water is mostly a natural phenomenon rather than a sign of industrial pollution. That said, natural doesn't automatically mean harmless.

Most people associate lithium with batteries or psychiatric medication. At high prescription doses, lithium carbonate treats bipolar disorder — and that medical history is exactly why researchers started paying closer attention to lithium in drinking water. At low levels, some studies suggest lithium may have mild neuroprotective effects. At higher levels, though, it can stress the kidneys and thyroid, particularly in people who already have reduced kidney function, pregnant women, and young children. The kidneys filter lithium from the blood, so anyone with impaired kidney function may accumulate it more easily. The World Health Organization (WHO) has flagged the need for more research on long-term, low-level lithium exposure through drinking water, noting that current evidence is still developing.

Right now, the EPA has not set a maximum contaminant level (MCL) for lithium in drinking water. That means there is no federal legal limit that water utilities must meet. The EPA has acknowledged lithium as a contaminant of concern, but formal regulation has been slow to follow. The Environmental Working Group (EWG) does not currently publish a specific health guideline for lithium either, which is why the data shows 0 systems reporting levels above a guideline — not because the levels are confirmed safe, but because no enforceable benchmark exists yet. Across 1,248 water systems tested, the average lithium level was 27.669 parts per billion (ppb), with a maximum detected level reaching 400 ppb. That upper range is worth watching.

Lithium shows up most frequently in states with specific geological profiles. Texas leads with 202 affected systems, followed by South Dakota (121), Iowa and Colorado (tied at 86 each), and Missouri (85). Texas and South Dakota sit atop mineral-dense geological formations where lithium-bearing rocks are common. Colorado's Rocky Mountain geology contributes similarly. Iowa and Missouri draw from aquifers that pass through lithium-rich sedimentary layers. If you live in any of these states and rely on well water or a smaller municipal system, your exposure risk is higher than average. Larger city utilities often blend water from multiple sources, which can dilute lithium concentrations — but smaller systems may not have that buffer.

The good news is that lithium is removable. Reverse osmosis (RO) filtration is the most effective method, removing up to 95–99% of dissolved lithium from drinking water. RO systems work by pushing water through a semi-permeable membrane that blocks dissolved metals and minerals, including lithium. Ion exchange filters also reduce lithium levels meaningfully. Standard carbon filters — the kind in many pitcher filters and refrigerator units — do not effectively remove dissolved metals like lithium, so they aren't the right tool here. If you're in a high-lithium state or want to know your specific levels, start with a certified water test. Echo Water's reverse osmosis systems are designed to address exactly this category of dissolved inorganic contaminants, giving you cleaner water without guesswork. Until the EPA establishes a formal limit for lithium, taking action at the tap is the most reliable way to protect your household.

Regulatory Standards for Lithium*

Cities With the Highest Lithium* Levels

States Most Affected by Lithium*

Frequently Asked Questions

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