40 CFR § 141.11 - Maximum contaminant levels for inorganic chemicals.
(a) The maximum contaminant level for arsenic applies only to community water systems. The analyses and determination of compliance with the 0.05 milligrams per liter maximum contaminant level for arsenic use the requirements of § 141.23.
(1) Such water will not be available to children under 6 months of age; and
(2) The non-community water system is meeting the public notification requirements under § 141.209, including continuous posting of the fact that nitrate levels exceed 10 mg/l and the potential health effects of exposure; and
(3) Local and State public health authorities will be notified annually of nitrate levels that exceed 10 mg/l; and
(4) No adverse health effects shall result.