Lithium in drinking water
A naturally occurring metal, high in some groundwater in the West and Southwest. Tested nationally for the first time under UCMR 5.
Health: No federal limit. EPA's screening level is 10 ppb, based on effects on the thyroid and kidneys at high doses (lithium is also a psychiatric medication).
Across the US
Those 2,627 systems serve about 84.1 million people.
From EPA's UCMR 5 testing, 2023–2025: every community system serving 3,300+ people and a sample of smaller ones.
Highest results
| Water system | People | Highest result |
|---|---|---|
| Waterpro Inc | 33,100 | 960 ppb |
| Creekside Village MHP | 115 | 921 ppb |
| Arizona Water Company – Apache Junction | 62,055 | 796 ppb |
| Aqua Pennsylvania Water Company Honesdale | 5,500 | 702 ppb |
| Bermuda Water Company Inc | 25,000 | 580 ppb |
| Bernalillo Water System | 11,810 | 537 ppb |
| City of Mesa | 466,000 | 525 ppb |
| Indianola Water Supply | 15,833 | 480 ppb |
| California American Water – Oakhurst | 3,710 | 474 ppb |
| City of Buckeye – Valencia Town Division | 30,377 | 468 ppb |
| Rio Rancho Water & Water Works Services | 107,350 | 467 ppb |
| Vermillion Water System | 11,695 | 440 ppb |
| Wapello Rural Water Association | 17,263 | 420 ppb |
| City of Woodway | 9,383 | 403 ppb |
| Coralville Municipal Water System | 22,318 | 390 ppb |
| Pima Utilities | 20,000 | 381 ppb |
| West Des Moines Water Works | 73,959 | 380 ppb |
| Mount Pleasant Municipal Utilities | 9,274 | 370 ppb |
| Arizona Water Company – Pinal Valley | 134,432 | 353 ppb |
| Laguna Valley Water System | 4,500 | 343 ppb |
| Goodyear Water Department | 50,001 | 335 ppb |
| Lower Rio Grande Pwwa South Valley Water System | 11,542 | 335 ppb |
| Anthony Water & Sewer District | 8,691 | 335 ppb |
| Woodridge Village Water System | 902 | 335 ppb |
| Tri County Special Utility District | 5,353 | 325 ppb |
States with the most detections
- Texas: 808
- California: 350
- Louisiana: 197
- Mississippi: 154
- Arizona: 151
- Missouri: 125
- Illinois: 116
- Iowa: 110
- Pennsylvania: 104
- Minnesota: 95
- Utah: 92
- Colorado: 92
Sources
The limits, health goals and health effects on this page come from these EPA sources. The results come from EPA's monitoring data for each water system.
- EPA: Fifth Unregulated Contaminant Monitoring Rule (UCMR 5)
- EPA: UCMR occurrence data (the test results)
This page summarizes public regulatory information. It is not medical advice. How we source and check this site.
Questions
What is the safe level of Lithium in drinking water?
There is no federal legal limit. EPA health reference level (HRL): 10 ppb.
How do I remove Lithium from tap water?
See the filter guidance on this page: look for a product certified for Lithium specifically, and check the claim in NSF's certified product listings.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.