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Homeland Security: Keeping an Eye on Our Drinking Water Supply

EPA researchers test commercial, readily-available water sensors for use in early warning systems for detecting biological and chemical contaminants in drinking water.

Glass filling with tap water

The vast majority of Americans need look no further than their kitchen faucet to find clean, abundant drinking water. The nation’s water distribution system is a model of success. Following the terror attacks of 2001, however, concern has grown over the risk of deliberate sabotage.

EPA researchers are working to lower that risk.

Scientists and engineers at EPA are working to verify and evaluate technologies to prevent, prepare for, and if necessary clean up biological, radiological, and chemical agents that could be used in a terrorist attack, including the deliberate contamination of public drinking water supplies and distribution systems.

Researchers in the program recently delivered some welcome news: sensors already widely used for real-time water quality monitoring offer the potential to also serve as early warning systems for detecting intentional contamination of drinking water systems.

Results of a series of tests EPA researchers conducted on the use of sensors to detect intentional contamination in drinking water distribution systems are highlighted in the recently-released Distribution System Water Quality Monitoring: Sensor Technology Evaluation Methodology and Results (PDF) (60 pp, 1.7 MB).

“Five years of EPA sensor detection data are summarized in the report.” says Jeff Szabo, one of the report co-authors.  “It is a useful tool for anyone involved in contamination warning system design or online monitoring research.”

The report summarizes the testing of various online, real-time water quality sensors to evaluate their ability to provide warning of intentional contamination. Only sensors that are already commonly used by water utilities were tested. The research team identified free chlorine and total organic carbon (TOC) sensors as the most successful technologies for detecting select biological and chemical contaminants.

The report provides a “lessons learned” section, a summary of estimated operation and maintenance costs, and recommends best practices for online sensor contaminant warning systems, including instrument set up and acquisition; testing procedures and safety precautions; data analysis; and operation, maintenance, and calibration of online instrumentation.

The research has led to contaminant warning system pilots conducted by water utilities in major cities throughout the country, helping ensure we continue to look no farther than the kitchen tap for our drinking water.

Learn more
Commonly Used Water Quality Sensors Can Detect Intentional Drinking Water Contamination

EPA research on water quality sensors supports the Agency’s Water Security Initiative, a program established in response to a Homeland Security Presidential Directive calling for the Agency to develop robust, comprehensive, and fully coordinated surveillance and monitoring systems.

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