Lithium occurs naturally in drinking water, and the amount varies with local geology and water sources. You can now look up measurements from many U.S. public water systems. Here's how to understand the units, the data, and the difference between a water result and a health recommendation.
How much lithium is in US drinking water?
Lithium in US drinking water is measured in micrograms per liter (µg/L) and varies enormously by location and source. A USGS national assessment of public-supply and domestic wells found lithium ranging from below 1 to 396 µg/L, with a public-supply median of about 8.1 µg/L, highest in arid regions and older groundwater (Lindsey and colleagues, 2021; DOI). A later USGS-led model grouped estimated concentrations across the conterminous US into four bands, ≤4, >4–≤10, >10–≤30, and >30 µg/L (Lombard and colleagues, 2024; DOI).
EPA’s UCMR 5 monitoring collected lithium samples during 2023–2025. Its minimum reporting level is 9 µg/L, a measurement threshold rather than a health threshold. Public data releases can be updated as results are processed. EPA explains the monitoring program and reference values.
Non-detect does not mean zero. It means the laboratory did not quantify lithium at or above the stated reporting limit. The exact amount below that limit is unknown; the result should not be assigned a made-up number.
How does lithium in water vary by state and region?
Groundwater lithium tracks local geology: areas with certain rock and aquifer types carry more lithium, so concentrations vary by state, metro area, and even neighborhood within a region. Arid regions and certain aquifers tend to be higher, and surface water (rivers, reservoirs) often differs from the groundwater beneath the same area. Because the variation is geological rather than political, state-level averages hide large within-state differences, and the four occurrence bands above are a more useful frame than any single state figure.
To see how this plays out where you live, explore our interactive map of EPA drinking water monitoring data, searchable by state and city.
How to read water lithium levels
Keep three things separate when you read a result:
- Concentration: µg/L is micrograms of lithium per liter of water. It is not a daily dose.
- Reporting limit: UCMR 5’s 9 µg/L level determines whether a result is quantified in that monitoring program.
- Health reference: EPA’s 10 µg/L health reference level provides monitoring context. It is not an enforceable limit or a nutritional target.
A USGS map’s concentration bands describe estimated occurrence, not categories of dementia protection. See EPA’s fact sheet and our testing guide.
Is lithium in drinking water good or bad?
Water-exposure studies have produced mixed findings. Some associate higher lithium with lower dementia or regional suicide rates; a Danish pregnancy study associated higher estimated exposure with autism diagnoses in children. These studies differ in design and cannot show that raising or lowering one person’s lithium intake will improve their health.
None establishes an optimal lithium concentration for brain health. Health reference values and environmental monitoring answer a different question from whether a nutrient or supplement improves memory.
The deeper evidence sits on the cluster pages: see lithium and dementia for the dementia epidemiology, lithium, mood and depression for the suicide-rate research, and the full studies database, by form to see how trace water-lithium evidence differs from carbonate and orotate evidence.
How do you test your water for lithium?
Check your supplier’s available lithium results first. A laboratory can test your tap or private-well water if you need a direct measurement. Ask about lithium specifically, including the method, reporting limit, sampling instructions, and price. Some water-quality reports include lithium; others do not.
Full detail: how to test your water for lithium →
Do water filters remove lithium?
Whether a filter removes lithium depends on the technology. An EPA study of multiple water-treatment sites found that reverse osmosis removed more than 90% of lithium, while conventional surface-water treatment, adsorptive media, biological/aerobic groundwater treatment, and manganese-removal filters were not effective; cation exchange was inconsistent, and lime softening removed 11–54% (Keithley and colleagues, 2025; DOI).
| Filter or treatment type | Effect on lithium (Keithley 2025) |
|---|---|
| Activated carbon / conventional treatment | Not effective for dissolved lithium |
| Reverse osmosis (RO) | Removed more than 90% of lithium |
| Ion exchange (cation exchange) | Inconsistent removal |
| Lime softening | 11–54% removal (often still above 10 µg/L) |
These results describe the systems studied. They do not certify every household filter or brand. Consumer filters may combine different media, and reverse-osmosis performance depends on the system, maintenance, and blending. Look for testing of the exact model.
Full detail: do Brita filters remove lithium? →
Is dietary lithium intake lower today than it used to be?
The studies cited here do not establish a historical decline in dietary lithium. Treatment research shows that some processes remove lithium, and food surveys show that sampled products differ. Neither tells us how a population’s total intake has changed over generations.
What we can say is more useful: lithium intake varies with food, water source, and treatment. There is no established dietary requirement against which to label that intake adequate or deficient.
Limitations and safety
Water-lithium epidemiology is almost entirely ecological: it compares regional water concentrations with regional disease rates and cannot establish that water lithium causes any outcome in an individual. Reported associations are inconsistent, appearing protective, null, or (prenatally) harmful depending on the outcome and concentration, and regional confounders such as socioeconomic status, geology, and longevity are difficult to disentangle. There is no US federal maximum contaminant level for lithium in drinking water, and there is no evidence basis for deliberately adding lithium to, or removing it from, household water for brain-health reasons. This article is educational and is not medical advice.
For how trace water-lithium fits within the wider research on lithium and the brain, see lithium and the brain: the complete guide and dietary lithium intake.
Frequently asked questions
How much lithium is in tap water?
It varies widely. A USGS assessment found public-well lithium from below 1 to 396 µg/L, with a median near 8.1 µg/L (Lindsey and colleagues, 2021), and a USGS model groups estimates into ≤4, 4–10, 10–30, and >30 µg/L bands (Lombard and colleagues, 2024). Many public systems report "non-detect" under EPA UCMR5, meaning below the laboratory reporting floor (commonly cited near 9 µg/L), which is not the same as zero. Local geology is the main driver.
Is lithium in drinking water dangerous?
There is no federal enforceable limit, but EPA uses a 10 µg/L health reference level to interpret monitoring results. A water number is not a health diagnosis. Ask your supplier or local public-health agency for context if a result concerns you.
Which states have the most lithium in water?
Lithium concentration follows geology, not state lines, and varies within states. Arid regions and certain aquifers tend to be higher. State averages hide large within-state differences, so the USGS occurrence bands described above are a more useful frame than any single state figure.
Does boiling water remove lithium?
No. Boiling does not remove dissolved lithium ions and can slightly concentrate them as water evaporates. Reverse osmosis is the most effective documented method (more than 90% removal), whereas conventional and carbon-based treatment are not effective (Keithley and colleagues, 2025).
Do Brita or carbon filters remove lithium?
These results describe the systems studied. They do not certify every household filter or brand. Consumer filters may combine different media, and reverse-osmosis performance depends on the system, maintenance, and blending. Look for testing of the exact model.
Should I add lithium to my water for brain health?
No. There is no evidence basis or safe established dose for adding lithium to household water, the population research does not prove benefit, and self-dosing lithium can be unsafe. Any interest in lithium should be discussed with a clinician.
References
- Fraiha-Pegado, de Paula, Alotaibi et al. (2024). Trace lithium levels in drinking water and risk of dementia: a systematic review. International Journal of Bipolar Disorders.
- Iordache, Voica, Roba et al. (2024). Lithium Content and Its Nutritional Beneficence, Dietary Intake, and Impact on Human Health in Edibles from the Romanian Market. Foods.
- Keithley, Jordan, Muhlen et al. (2025). Lithium Removal From Drinking Water. AWWA Water Science.
- Kessing, Gerds, Knudsen et al. (2017). Association of Lithium in Drinking Water With the Incidence of Dementia. JAMA Psychiatry.
- Liew, Meng, Yan et al. (2023). Association Between Estimated Geocoded Residential Maternal Exposure to Lithium in Drinking Water and Risk for Autism Spectrum Disorder in Offspring in Denmark. JAMA Pediatrics.
- Lindsey, Belitz, Cravotta et al. (2021). Lithium in groundwater used for drinking-water supply in the United States. Science of The Total Environment.
- Lombard, Brown, Saftner et al. (2024). Estimating Lithium Concentrations in Groundwater Used as Drinking Water for the Conterminous United States. Environmental Science & Technology.
