Other
Diquat in U.S. tap water
27 public water systems across 3 U.S. states report Diquat in their annual Consumer Confidence Report. None currently sit at or above the federal limit.
Approaching the limit (1)
| Water system | Measured | vs. limit |
|---|---|---|
| Ontario, CA 2024 annual report | 18 ug/L | 0.9× the limit |
Within the federal limit (26)
Diquat by state
Every state where a public water system reports Diquat in its annual report, ranked by systems at or above the federal limit.
| State | Measuring | Over limit | Highest reading |
|---|---|---|---|
| California | 24 | 0 | 18 ug/L · Ontario, CA |
| Alabama | 2 | 0 | Not detected ug/L · Mobile, AL |
| Tennessee | 1 | 0 | Not detected mg/L · Nashville, TN |
Frequently asked
+What is Diquat?
Diquat is a contaminant some U.S. public water utilities measure and report in their annual Consumer Confidence Report.
+Does Diquat have a federal limit in drinking water?
Diquat does not have an enforceable federal MCL. Utilities still report any measured levels in their annual Consumer Confidence Report.
+How many U.S. water systems have Diquat over the federal limit?
Zero of the 27 public water systems in The Water Map dataset currently report Diquat at or above its federal limit.
+Which states report the most Diquat in their drinking water?
No state currently has a system reporting Diquat at or above its federal limit in The Water Map dataset. California, Alabama, Tennessee have the most systems measuring it.
+How can I check if Diquat is in my city's tap water?
Search your city on The Water Map (https://www.thewatermap.com/) or browse the list on this page. Every U.S. public water utility is required to publish an annual Consumer Confidence Report that lists every contaminant it measured, including Diquat.