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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Real EPA measurements of thallium for Washington water systems — Six-Year Review compliance samples 2012–2019 (historical). Methodology
EPA does not publish per-city thallium measurements for Washington in the datasets we use, so this section shows what regulators actually recorded: every Safe Drinking Water Act violation tied to thallium at the 4 Washington public water systems we track, since 2016. Source: EPA SDWIS via ECHO (2026 Q2 extract).
No thallium violations on record. None of the 4 tracked Washington systems has a SDWIS violation for thallium since 2016. That means no monitoring, reporting or limit violation was logged — it is not a lab result for your tap. Check your utility's annual Consumer Confidence Report for measured levels.
Every Washington system with a thallium result in EPA's data, sorted by level. Averages of 2012–2019 finished-water samples, non-detects counted as zero — historical, not today's tap.
No thallium detections have been reported in Washington cities.
Thallium is a highly toxic heavy metal. Short-term exposure can cause gastrointestinal irritation, nerve damage, and blood chemistry changes. Long-term exposure causes hair loss, changes in blood chemistry, damage to liver, kidney, intestinal, and testicular tissues, and neurological damage including numbness and muscle weakness.
Leaching from ore-processing sites; discharge from electronics, glass, and drug factories
Based on our analysis of EPA Safe Drinking Water Information System (SDWIS) data and local water utility reports,thallium has been detected in 0 Washington water systems.
The EPA MCL for thallium is 0.002 mg/L (2 ppb). The EPA MCL for thallium is 0.002 mg/L. This limit is set to protect public health based on available scientific evidence about the contaminant's health effects.
0 Washington cities have thallium detected in their water supply. All tested cities are within EPA safety limits.
Hair loss, nerve damage, liver and kidney damage, gastrointestinal effects. The most vulnerable groups include children and pregnant women.
The most effective methods for removing thallium include Reverse Osmosis, Ion Exchange, Distillation. Look for filters certified by NSF/ANSI for thallium reduction.
The EPA Maximum Contaminant Level (MCL) for thallium is 0.002 mg/L.The EPA MCL for thallium is 0.002 mg/L (2 ppb).
This page shows what Washington utilities reported for thallium. It cannot tell you what is coming out of your own tap: utility samples are taken across a whole system and averaged, levels vary by address and season, and anything picked up after the water leaves the main never appears in their report.
Home water test kitscheck your own tap before buying any filterRecommended filtration methods for thallium removal:
Very effective for thallium
Effective for heavy metals
Removes heavy metals
Paid links. We earn a commission if you buy, at no extra cost to you. Filters are matched to the removal methods listed above for thallium.