Frozen in 2001
The federal arsenic standard of 10 ppb was finalized in 2001 and has never been updated, despite two decades of cancer-incidence data calling for a sub-1 ppb limit.
Peer-reviewed thresholds
Health guidelines used here are sourced from the California OEHHA, the U.S. EPA Integrated Risk Information System, and meta-analyses published in peer-reviewed toxicology journals.
Transparent methodology
Every multiplier on the platform is computed as (utility detected level) ÷ (health guideline). We never hide the math — every row is auditable.
Comparative table
EPA Legal Limit vs. Independent Health Guideline
Arsenic
Effect: Bladder, lung & skin cancer
Unit: ppb
Health Guideline
0.004
EPA Legal Limit
10
Legal is
2,500×
above health guideline
Total Trihalomethanes (TTHMs)
Effect: Cancer; fetal development harm
Unit: ppb
Health Guideline
0.15
EPA Legal Limit
80
Legal is
533×
above health guideline
Hexavalent Chromium (Cr-6)
Effect: Stomach & gastrointestinal cancer
Unit: ppb
Health Guideline
0.02
EPA Legal Limit
100
Legal is
5,000×
above health guideline
Nitrate
Effect: Cancer; blue-baby syndrome
Unit: ppm
Health Guideline
0.14
EPA Legal Limit
10
Legal is
71×
above health guideline
Radium 226 + 228
Effect: Cancer; bone toxicity
Unit: pCi/L
Health Guideline
0.05
EPA Legal Limit
5
Legal is
100×
above health guideline
PFOA (Forever chemical)
Effect: Immune, thyroid, kidney cancer
Unit: ppt
Health Guideline
0.0079
EPA Legal Limit
4
Legal is
506×
above health guideline
Editorial Note
The standards your family drinks under were written in a different century.
Updating a single federal drinking-water standard now requires an average of 17 years of regulatory review — far slower than the pace at which new contaminants enter the supply.
Until the legal framework catches up, household-level filtration remains the single most effective public-health intervention an individual family can take.