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.