Marine Corps Base Quantico (MCBQ) routinely monitors drinking water to ensure compliance with National Primary Drinking Water Regulations. During the third quarter of 2025, we discovered that our water system exceeded the Primary Maximum Contaminant Level (PMCL) for Total Trihalomethanes (TTHM) at two sampling locations: Bobo Hall and 2700 Block Tank. The average level of TTHM over the compliance period (fourth quarter 2024 through third quarter 2025) was 0.093 mg/l at Bobo Hall and 0.092 mg/l at 2700 Block Tank, exceeding the standard of 0.080 mg/L.

This is not an immediate risk. If it had been, you would have been notified immediately. You do not need to use an alternative (e.g., bottled) water supply, or boil your water.

What happened?

The elevated TTHM levels were caused by a reduced flow of water due to the remote location of the sampling sites. This allowed increased contact time between chlorine and natural organic matter, resulting in excess buildup of TTHM. Some people who drink water containing high levels of TTHM over many years may experience problems with their liver, kidneys, or central nervous system, and may have an increased risk of getting cancer. There are no immediate health risks based on these levels; however, if you have specific health concerns, consult your doctor.

What is being done?

We are assessing our water treatment and distribution systems to address elevated TTHM levels at two sampling locations. This includes additional sampling of the treatment process, a review of treatment process data, and optimization of coagulation, filter backwash, and chemical dosing to limit natural organic matter and byproduct formation. We are also evaluating current flushing programs, with potential measures such as increased line flushing and more frequent water storage tank turnover to reduce water age. Disinfection byproduct levels will be re-tested in November 2025 per MCINCR-MCB Quantico’s regulatory schedule.

Additional Information:

Please share this information with all others who drink this water, especially those who may not have received this notice directly. You can do this by posting this notice in a public place or distributing copies by hand or email.

For more information, visit http://www.quantico.marines.mil/Water-Quality/, or contact Dr. HunHo Kim, Supervisory General Engineer, at 703-432-2466. This notice is being sent to you by MCINCR-MCB Quantico Installation and Environment Division (GF).

Date distributed: 10 October 2025