Thallium in Drinking Water
EPA limits, health effects, and what to do if your water is affected.
🩨 Health Effects
Long-term exposure above the MCL causes hair loss, changes in blood and kidneys, intestines, and liver. Thallium is highly toxic; acute high-level exposure can be fatal.
📍 Sources in Water
Enters water from leaching at ore-processing sites and from electrical, glass, and pharmaceutical industries. Thallium contamination in water is rare but has occurred near mining operations.
✅ What To Do
Reverse osmosis and activated alumina are the most effective treatment methods. Thallium violations in public water systems are very rare.
Check your tap water for Thallium
Search your ZIP code to see if your water system has had Thallium violations, plus lead testing results and an overall safety grade.
Search your ZIP code →Data from the EPA's Safe Drinking Water Information System (SDWIS). MCLs reflect minimum federal standards; some contaminants may pose health risks below these thresholds.