Hexavalent Chromium

Chromium is naturally occurring in soils, rocks, plants, humans and animals, and therefore could enter the source water from anywhere in our watershed. Certain industrial processes are also a source. These include steel manufacturing, pulp mills and chrome plating operations. Based on Prince William Water’s Industrial Pretreatment Survey results, we are unaware of any such manufacturing facilities in Prince William County.

Facts about Hexavalent Chromium

• Chromium has three common forms: trivalent (Cr3+), hexavalent (Cr6+) and elemental (Cr0).
• The Environmental Protection Agency (EPA) regulates hexavalent and trivalent chromium together as total chromium. It does not regulate hexavalent chromium separately.
• The maximum contaminant level (MCL) for total chromium is 100 parts per billion (ppb). Any water purveyor that exceeds 100 ppb of total chromium must notify the public and is in violation of the Primary Drinking Water Regulation for chromium.
• All Prince William Water water quality results comply with the current MCL.
• As part of the EPA’s Third Unregulated Contaminant Monitoring Rule (UCMR 3) that took place between 2013 and 2015, all water purveyors serving more than 10,000 people were required to test for a list of pollutants that included hexavalent chromium. Every five years, the EPA reviews and selects a list of unregulated contaminants to be monitored by public water systems. This study benefits the environment and public health by providing valid data on the occurrence of contaminants in drinking water. The EPA uses this data to develop regulatory decisions for emerging contaminants. Prince William Water participated in this study in 2014.
• Results of the UCMR 3 study conducted in 2014 for hexavalent chromium in Prince William Water’s East System ranged from 0.07 - 0.13 ppb. Results in the West System ranged from Not Detected (ND) - 0.16 ppb.  
• Prince William Water meets all requirements outlined in the Safe Drinking Water Act (SDWA). The SDWA is the federal law that protects public drinking water supplies throughout the nation. This gives Prince William Water confidence in the quality of the water it provides to customers. If or when the EPA establishes new standards concerning hexavalent chromium, Prince William Water will meet them.
• Prince William Water does not provide advice on any point-of-use treatment options or equipment for lowering hexavalent chromium in their tap water. Those seeking advice on which devices to install in their homes or businesses should consult with the manufacturers.
• Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompromised persons, such as people with cancer undergoing chemotherapy, people who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly individuals and infants may be at higher risk. Those with health concerns should seek advice about drinking water from their health care providers.