For residents of Green Bay, Wisconsin, Arsenic has appeared in public water supply sampling data.

Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-05-14

Arsenic in Green Bay Tap Water

Arsenic has been detected in Green Bay, Wisconsin drinking water at a maximum level of 9.5 ppb — below the EPA MCL of 10 ppb.

This analysis covers 177,103 residents across 12 ZIP codes in Green Bay.

Green Bay's overall water quality grade is B (78/100).

Is Arsenic in Green Bay Water Safe?

Arsenic was detected in Green Bay water but currently falls within EPA limits. However, some health organizations argue the EPA MCL may not be protective enough.

If you are concerned, a reverse osmosis filter can reduce arsenic levels further.

Arsenic Levels by ZIP Code

Average arsenic level across Green Bay: 9.5 ppb

Health Effects of Arsenic

• Increased risk of skin, bladder, lung, and kidney cancer
• Cardiovascular disease and type 2 diabetes
• Skin changes (darkening, thickening, lesions)
• Developmental effects in children exposed in utero

Health risk severity: High. Governed by the Arsenic Rule (2006).

How Arsenic Gets Into Drinking Water

• Natural deposits in rock and soil (especially in western U.S.)
• Runoff from orchards and glass/electronics production
• Historical use of arsenic-based pesticides
• Well water in areas with arsenic-rich geology

What to Do About Arsenic in Green Bay Water

1. Install a reverse osmosis (RO) system certified under NSF 58
2. Adsorptive media filters (iron-based) can also reduce arsenic
3. Have well water tested if on a private supply
4. Boiling water does NOT remove arsenic — it concentrates it

Look for filters certified under NSF 53 / NSF 58 for arsenic removal.

Related

• Arsenic — National Overview
• Arsenic in Wisconsin
• Wisconsin Water Quality
• Green Bay Water Quality
• Check Your ZIP Code