Chromium-6, linked to stomach, liver, and reproductive health risks, is present in water supplied to 251 million Americans, yet the EPA does not regulate its specific levels, only total chromium, despite evidence of health risks at lower levels.

Nitrate contamination, mainly from agricultural runoff and present in many water sources, is linked to cancers, birth defects, and preterm birth, yet the EPA’s current limit of 10 ppm is outdated, with new research indicating health risks below this threshold.

Analysis of over a decade of data from more than 17,000 community water systems shows that arsenic and hexavalent chromium (chromium-6) often co-occur in water supplies and can be effectively treated together using the same technologies.

Individuals are encouraged to use home water filters, particularly reverse osmosis systems, and to check their tap water quality via EWG’s database to reduce exposure to harmful chemicals.

Current regulatory practices evaluate contaminants separately, which leads to inefficiencies and increased health risks, especially for small and rural water systems that often lack the resources to upgrade infrastructure.

Arsenic, found in all 50 states and associated with bladder, lung, and skin cancers, has a federal limit of 10 parts per billion (ppb), but scientists recommend a much lower level of 0.004 ppb, with California aiming for this standard to eliminate cancer risk.

Reducing arsenic levels by 27% to 42% in systems with chromium-6 could potentially quadruple the number of prevented cancer cases compared to focusing solely on chromium-6 reduction.

A new peer-reviewed study by the Environmental Working Group (EWG) highlights that treating tap water for multiple contaminants simultaneously could prevent over 50,000 lifetime cancer cases in the U.S., challenging the traditional approach of regulating one contaminant at a time.

Proven treatment technologies like ion exchange and reverse osmosis can remove several harmful contaminants at once, offering a cost-effective solution to improve water safety and public health.

EWG advocates for updating water regulations to consider multiple contaminants simultaneously, citing the effectiveness of these technologies in addressing co-occurring pollutants such as arsenic, chromium-6, and nitrate.

The study emphasizes that treating multiple contaminants simultaneously is more effective and efficient, especially for small and rural communities that often lack resources for infrastructure upgrades, and advocates for a shift in federal and state water regulations towards multi-contaminant treatment approaches.