EPA Reference Ranges
“Contaminant” or Parameter |
EPA Maximum Level-Mg/L (ppm) |
ppb (ug/L) |
Source |
Health Effects |
Total Chlorine |
4.0 |
|
Water disinfectant |
Stomach discomfort |
Cadmium |
0.005 |
5 |
Heavy metal |
Kidney Damage |
Copper |
1.3 |
1300 |
Heavy metal |
Liver & Kidney Damage |
Lead |
0.015 |
15 |
Heavy metal |
Learning disorders in children, high blood pressure in adults |
Mercury |
0.002 |
2 |
Heavy metal |
Kidney damage |
Nitrate |
10.0 |
|
From fertilizers & animal waste |
Blue baby syndrome (age 6 and below), illness or death |
Nitrite |
1 |
|
From fertilizers & animal waste |
Blue baby syndrome and shortness of breath |
E.coli |
Negative result by testing |
|
Bacterial contamination |
Indicates water contamination and causes intestinal illness |
|
Non-EPA regulated but recommended |
|
|
|
pH |
Ideal 6.5-8.5 |
|
Measure of acidity in water |
Acidic pH causes pipe corrosion and heavy metal leaching from plumbing |
Hardness |
10-100 mg/L (ppm) |
|
Minerals |
Causes mineral scale, clogs faucets, damages water heaters |
Alkalinity |
75-150 mg/L (ppm) |
|
Minerals |
Low alkalinity is associated with acidic pH and corrosion |
Hydrogen sulfide |
0 mg/L |
|
Sulfur gas forming in water supply or water heater |
Causes rotten egg odor and bad taste |
Notes: The EPA uses mg/L (ppm) or ppb = microgram/L (ug/L), depending on the document.