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Lithium in drinking water: a plain-English guide

Lithium is a naturally occurring element found in trace amounts in many U.S. groundwater sources. Therapeutic doses in psychiatry are orders of magnitude higher than typical drinking-water exposure. EPA has not set a regulatory limit; the non-enforceable Health Advisory Level is 0.04 mg/L. Tested nationwide under UCMR 5 (2023-2025) alongside 29 PFAS chemicals.

Where lithium in drinking water comes from

Lithium is a naturally occurring alkali metal found in some rock formations (granite, pegmatite, shale) and in geothermal water. It enters drinking-water sources by simple weathering of those rocks. Industrial contributions exist (lithium-ion battery manufacturing, ceramics, some pharmaceuticals) but are localized; the dominant U.S. source in drinking water is geology.

Concentrations vary by orders of magnitude across U.S. systems. EPA’s UCMR 5 sampling (2023-2025) found lithium above the minimum reporting level in a substantial fraction of tested public water systems, with the highest values clustered in the Southwest, parts of Texas, and the Great Plains.

Why it’s worth tracking

Lithium is medically used to treat bipolar disorder and treatment- resistant depression at doses of roughly 600 to 1,800 mg per day. At those doses, lithium has a narrow therapeutic index: too little is ineffective, too much causes kidney damage, thyroid disease, and acute neurotoxicity. Pregnancy exposure at therapeutic doses is associated with congenital heart defects, particularly Ebstein’s anomaly.

Drinking-water exposure is dramatically lower. At the EPA Health Advisory Level of 0.04 mg/L (40 µg/L), a person drinking 2 liters per day receives 0.08 mg of lithium daily, roughly 10,000 times less than a typical psychiatric dose. The active scientific question is whether environmental exposure orders of magnitude below therapeutic doses produces population-level effects.

Several ecological studies have reported associations between higher naturally occurring lithium in drinking water and lower suicide rates, lower dementia incidence, and reduced violent-crime rates. Other studies have found no effect. The literature is mixed and not policy-actionable; no public-health agency currently recommends lithium fortification of drinking water, and no agency treats current drinking-water levels as a known hazard.

EPA regulation

  • No enforceable MCL. Lithium is on EPA’s Contaminant Candidate List 5 (CCL 5), meaning it is under consideration for future regulation but is not currently regulated.
  • Health Advisory Level: 0.04 mg/L lifetime advisory, set in 2024. Non-binding; published to inform utilities and the public, not to require action.
  • UCMR 5 monitoring: every public water system serving more than 3,300 people was required to test for lithium between 2023 and 2025, alongside 29 PFAS chemicals.

The HAL is not enforceable. A utility above the HAL is not in violation of any rule.

Special populations

Talk to a clinician about drinking-water lithium exposure if any of the following apply:

  • Pregnancy or planned pregnancy (lithium is a known teratogen at therapeutic doses)
  • Current lithium prescription: drinking-water lithium adds to total daily intake, however slightly. A nephrologist or psychiatrist managing your dose should know your water source.
  • Thyroid disease or chronic kidney disease

For the general population at typical U.S. drinking-water levels, no specific action is recommended.

Treatment

If you choose to remove lithium from drinking water:

  • Reverse osmosis (most effective at the point-of-use)
  • Strong-acid cation exchange (whole-house)

Activated carbon does NOT remove lithium. Boiling concentrates it.

This page is general information, not medical advice.

Sources

Editorial review: reviewed 2026-05-11 by RK 2026-05-11. Editorial standards.