Notice to MCB Quantico Residents
1 Sep 2023

The Marine Corps Base Quantico Team want to make certain that all service members, residents and employees aboard the base understand that we are working at all levels to ensure the highest quality of life is afforded to everyone who calls Marine Corps Base Quantico home.

Regarding the water issues that we were experiencing this past week, we sincerely thank you for your diligence in reporting the issue, as well as your patience while the entire Marine Corps Base Quantico team worked to resolve.

Upon receipt of the initial concerns on August 29th, our Public Works department along with the teams at Liberty Housing, Environmental Affairs, and Naval Health Clinic Quantico worked quickly to understand the issue from multiple frames of reference and develop ways to solve the problem as quickly and safely as possible. Water Treatment Plant operators tested water samples from raw water (water that has yet to be treated using the Mainside Water Treatment Plant process) and finished water (which has been treated and is ready to be sent to the water distribution system). The results showed high concentrations of manganese in the raw water (0.38 mg/L) and finished water (0.12 mg/L). This shows an increase from the levels reported in Marine Corps Base Quantico’s historical average of approximately 0.04 mg/L. The Naval Health Clinic Preventative Medicine team worked closely with Public Works and Liberty Housing to quickly ensure this concern posed no threat to human health and has taken steps to conduct water surveillance of the affected housing areas.

The 0.12 mg/L of manganese in the finished water exceeds the Environmental Protection Agency's secondary drinking water standard of 0.05 mg/L.  However, the secondary drinking water standard is non-mandatory and established as a guideline to assist water systems in managing their drinking water for aesthetic (not health) considerations.

As soon as Public Works learned of the water discoloration issue in affected areas in base housing, spot flushing through hydrants and Uni-directional flushing were immediately conducted in the reported areas as a systematic and proactive approach to resolve the water discoloration in the distribution system.

After the discovery of a high concentration of manganese, treating those levels efficiently and effectively, required the Public Works branch to increase the chlorine dosage before the filtration process within the Mainside Water Treatment Plant. Increasing the dosage of chlorine before the filtration process, still within safe levels, helped change the chemical makeup of the manganese and allowed for the manganese to be filtered more easily at the Water Treatment Plant.  This minimized the formation of blackish brown manganese precipitates in the distribution system and prevented water discoloration at your taps.  Changing the dosage of chlorine before the filtration process did not result in increases to chlorine levels in the finished water, which are required to be present for safe drinking water.

Along with these actions, our Public Works team has also continued conducting daily samples of water from housing spigots to ensure we maintain up to date and accurate levels of manganese from the affected areas. These tests from samples collected on August 30 and 31 showed significant improvement in water quality.  Manganese levels measured from seven distribution samples within housing areas are still relatively high (0.04 – 0.09 mg/L) compared to EPA non-mandatory secondary manganese standard of 0.05 mg/g. 

These actions have resulted in Public Works receiving reports of clear water from residents living in the previously affected area. With on-going water treatment improvement efforts along with upcoming Fall Uni-direction flushing, manganese levels in the distribution system are expected to continually decrease and we are confident that the actions we have taken have resolved discoloration in your water.

Again, we would not have been able to respond as quickly and effectively without your continued communication with Liberty Housing and our base staff. We will continue to monitor all aspects of water quality to ensure every family, dependent, servicemember, and civilian employees on Marine Corps Base Quantico has access to safe drinking water. If you are still experiencing issues with your water quality, please email Marine Corps Base Quantico at immediately with your concerns so that we can appropriately address your concerns.

For more information about the water quality and to stay up to date on the base’s year round efforts to ensure we are providing the safest water available, please visit

Marine Corps Base Quantico