Lithium in Drinking Water: What the First EPA Data Shows

What is lithium in drinking water?

Lithium is a naturally occurring alkali metal that dissolves into groundwater as water passes through lithium-bearing rocks — particularly spodumene, lepidolite, and other mineral deposits. It enters surface water through natural weathering and industrial discharge.

Unlike most drinking water contaminants, lithium has a dual identity: it is both a trace mineral with potential biological activity and the active ingredient in psychiatric medication at much higher doses. That duality is why its presence in tap water is worth understanding, even though most people's exposure from water is orders of magnitude below any pharmacological effect.

Natural and industrial sources

UCMR5: what the first national lithium monitoring found

EPA's Fifth Unregulated Contaminant Monitoring Rule (UCMR5), which ran from 2023 to 2025, is the first time lithium has been systematically measured in US public water systems. The data covers thousands of utilities serving communities across the country and provides the most complete picture of national lithium exposure from tap water ever assembled.

UCMR5 results show that lithium in tap water is widespread — detected in systems across dozens of states, with higher concentrations concentrated in areas with lithium-rich geology such as parts of the Southwest, Mountain West, and Nevada basin. Most detections fall well below 10 µg/L, but some systems in high-geology areas have measured levels above 100 µg/L.

EPA is using UCMR5 data to determine whether a Maximum Contaminant Level (MCL) is warranted. No MCL has been proposed as of mid-2026. The monitoring data is public and feeds directly into this site's utility reports — you can check your specific water system below.

Is lithium in drinking water safe?

For most adults, tap water lithium levels are unlikely to cause harm. The concentrations found in UCMR5 are typically thousands of times lower than therapeutic doses. Neither the EPA, WHO, nor any major health authority has established a drinking water limit, which reflects the current assessment that typical exposure does not present an acute risk to the general population.

The picture is more nuanced in two directions:

The possible benefit: neuroprotection at trace doses

Several epidemiological studies have found that regions with higher naturally occurring lithium in tap water have lower rates of suicide, dementia, and certain psychiatric conditions. A 2009 Japanese study by Ohgami et al. found an inverse correlation between tap water lithium and suicide mortality across 18 municipalities. Similar findings have been reported in Texas, Austria, and the UK.

These are population associations, not randomised trials. They cannot establish causation, and confounding factors (diet, urban density, healthcare access) are difficult to fully isolate. No health authority has acted on this research by recommending lithium supplementation through water supplies.

The possible concern: vulnerable populations

Three groups have legitimate reason to pay closer attention to their lithium exposure from water:

• People taking lithium medication. Lithium carbonate has a narrow therapeutic window — the difference between an effective blood level and a toxic one is small. Any additional consistent source of dietary lithium, including water, can affect the balance and complicate dosing. People on lithium therapy should tell their prescriber if they learn their water supply contains elevated lithium.
• People with chronic kidney disease. The kidneys are the primary route for lithium excretion. Impaired kidney function can cause lithium to accumulate. People with CKD stages 3–5 should discuss their water lithium levels with their nephrologist.
• Pregnant women and infants. Therapeutic lithium during pregnancy is associated with a small increased risk of cardiac malformations. Evidence at trace water concentrations is far less clear, but the developing fetal brain and kidneys are generally more sensitive to mineral exposures. The precautionary principle applies particularly when exposure is easy to reduce.

How to remove lithium from tap water

Lithium is a dissolved ion — it behaves like other dissolved minerals in water and is not removed by activated carbon filtration. The filters that work are those designed to remove dissolved solids, not just particles and organic compounds.

If you are in one of the three higher-risk groups above, a reverse osmosis system installed under the kitchen sink is the most practical solution for consistent lithium reduction across all drinking and cooking water. Look for NSF/ANSI 58 certification — this confirms the membrane meets performance standards for dissolved-solid removal.

For the general population with no specific risk factors, reducing lithium from tap water is optional. The data does not currently support treating it as a priority contaminant for healthy adults.

Note on water ionizers (Kangen or similar): The built-in carbon pre-filter reduces chlorine but does not remove dissolved lithium ions. Electrolysis changes water pH and ORP — it does not function as a dissolved-solids filter. For lithium reduction, a dedicated reverse osmosis or deionisation system is required alongside any ionizer.

What to do if lithium is detected in your water

A practical approach based on your situation:

1. 01Check your utility's UCMR5 result using the ZIP tool above. Note the level in µg/L and whether it's above or below 10 µg/L.
2. 02Assess your risk profile. Are you taking lithium medication, have kidney disease, or are you pregnant or feeding an infant? If none of these apply, no action is required at typical detected levels.
3. 03If you are in a higher-risk group and your utility detected lithium above 10 µg/L, discuss with your doctor or nephrologist before deciding on filtration.
4. 04If you choose to filter, select an NSF 58 certified reverse osmosis system for under-sink installation. ZeroWater pitchers are a lower-cost alternative for drinking water only.
5. 05If you take lithium medication, tell your prescriber your tap water lithium level — it may be relevant to your dose management and monitoring schedule.

Frequently asked questions

Sources and methodology

• US EPA (2023). Unregulated Contaminant Monitoring Rule 5 (UCMR5). epa.gov/dwucmr/fifth-unregulated-contaminant-monitoring-rule
• Ohgami, H., Terao, T., Shiotsuki, I., Ishii, N., & Iwata, N. (2009). Lithium levels in drinking water and risk of suicide. British Journal of Psychiatry, 194(5), 464–465.
• Kabacs, N., Memon, A., Obinwa, T., Stochl, J., & Perez, J. (2011). Lithium in drinking water and suicide rates across the East of England. British Journal of Psychiatry, 198(5), 406–407.
• Szklarska, D., & Rzymski, P. (2019). Is lithium a micronutrient? From biological activity and epidemiological observation to food fortification. Biological Trace Element Research, 189, 18–27.
• Liaugaudaite, V., Mickuviene, N., Raskauskiene, N., Naginiene, R., & Sher, L. (2017). Lithium levels in the public drinking water supply and risk of suicide. Journal of Trace Elements in Medicine and Biology, 43, 197–201.
• Memon, A., Rogers, I., Fitzsimmons, S. M. D., et al. (2020). Association between naturally occurring lithium in drinking water and suicide mortality: systematic review and meta-analysis. British Journal of Psychiatry, 217(6), 667–678.
• US EPA (2022). UCMR5 Health Reference Levels. epa.gov/dwucmr
• World Health Organization (2020). Lithium in Drinking Water: Background Document for Development of WHO Guidelines for Drinking-water Quality. WHO/HEP/ECH/WSH/2020.6.
• NSF International. NSF/ANSI 58: Reverse Osmosis Drinking Water Treatment Systems. nsf.org
• WaterHealthCheck UCMR5 ingestion pipeline: data sourced directly from EPA UCMR5 occurrence data file, aggregated per public water system. See our methodology.