This paper examines the GuardianBlue Early Warning System, the first drinking water monitoring technology certified by the U.S. Department of Homeland Security under the Safety Act. The paper describes the system's core components — the Event Monitor, Water Panel, TOC Analyzer, and Automatic Samplers — and explains how each contributes to real-time contaminant detection. It analyzes the system's strengths, including early detection of pipe bursts, identification of chemical overfeeds, and continuous quality monitoring, as well as its limitations regarding alarm testing. The paper also addresses cost justification, operational benefits, and overall acceptability among water utility personnel, concluding with a strong recommendation for widespread deployment.
Is the nation's drinking water supply safe from terrorist attack? Overall, the danger of contamination of drinking water through terrorist activity is small, but it can still happen. Many people do not realize that most contaminants would need to be introduced in very large quantities, which reduces the likelihood of a credible threat. Treatment processes already in place will neutralize many pollutants. In addition, following the catastrophic events of September 11, 2001, drinking water utilities across the country were warned about the need to increase security and have since adopted enhanced monitoring and protection measures.
GuardianBlue is one of those protections designed for use in extreme cases. GuardianBlue is the first and only wastewater early warning system to be certified and designated by the U.S. Department of Homeland Security for monitoring drinking water. The system is powered by its Agent Library — a proprietary database that enables the GuardianBlue Event Detection System to detect and classify 34 contaminants of greatest concern to drinking water operators and the USEPA. The system is capable of identifying water quality events within minutes and distinguishing clearly among fluoride overfeeds, pesticide contamination, chemical warfare agents, and cyanide.
Since 9/11, numerous communities have installed multi-parameter monitoring stations at many points throughout their distribution systems as early warning systems based on potential water security threats. These continuous online systems have recorded vast streams of data relevant to water quality in the distribution networks where they have been deployed. Data streams from a number of communities — both small and large — have been analyzed for information pertaining to the health and operation of distribution systems.
Changes in water quality are correlated with known causes attributable to day-to-day operational changes such as source water switching, chlorine shocking, pumps turning on and off, and pressure surges. They are also correlated with anomalous events such as pipe bursts, accidental backflows, cross-connections, chemical overfeeds, treatment plant problems, and nitrification events. Information concerning what action, if any, was taken to address the problem is also linked to the data for identified events. The data streams likewise reveal the diversity of what might be considered "normal" operating conditions, both within and between different classes and types of systems. This kind of information is critical for understanding and improving distribution system operations and is also valuable when considering regulations that affect those operations.
With GuardianBlue, common water quality events can be detected quickly. The GuardianBlue Event Detection System is also equipped with the ability to learn water quality events that are unique to the specific water being monitored. Users of the system can label learned events and assign an importance level, allowing GuardianBlue to log incidents and alert users to new and recurring events.
GuardianBlue is the first and only early warning system for drinking water to have earned both the Safety Act designation and certification from the U.S. Department of Homeland Security. "Designation" indicates the product has qualified as an anti-terrorism technology, while "certification" confirms that the product is accepted for homeland security purposes. GuardianBlue's Event Monitor, Water Panel, and TOC Analyzer have also undergone Environmental Technology Verification (ETV) conducted by the EPA for continuous multi-parameter water monitoring in distribution systems. Hach's GuardianBlue Early Warning System has demonstrated the ability to alarm on at least 100% of all contaminants injected into the system during ETV testing.
The Event Monitor analyzes all sensor data received from the Water Panel and the TOC Analyzer in order to identify whether water has been tampered with in the event of a terrorist attack. Should an assault on the water supply occur, approximately every 60 seconds the system applies a patented algorithm directly to sensor measurements and calculates the site's water quality baseline. The system sends an alarm as soon as a trigger indicator exceeds a user-set threshold, signaling a water quality anomaly referred to as an "event." The event's fingerprint is then compared against fingerprints stored in both the Plant Library and the Agent Library, and utility supervisors are alerted when a match is found. If no match is identified, utility operators are notified of an unknown deviation in water quality, and the event's fingerprint is placed in the Plant Library for further examination, documentation, and classification (Berry, Hart, and Phillips).
Positioned at the core of the system, the Agent Library represents the most scientifically advanced analytics software available for water quality monitoring. The Agent Library contains fingerprints for a broad range of threat contaminants. When the Agent Library matches an event to the fingerprint of a threat contaminant, it also provides a confidence score to assist operators in making appropriate response decisions.
The Water Panel continuously monitors free or total chlorine, pH, turbidity, conductivity, temperature, and pressure, transmitting this data to the Event Monitor via digital communication. As soon as an event occurs, the Water Panel begins detecting changes in water quality parameters. The Water Panel incorporates Hach's leading water quality instruments and has become an industry standard for water quality monitoring.
The TOC Analyzer continuously measures total organic carbon. It uses EPA Method 415.1 to achieve its analytical capabilities, ensuring accurate results (Hach Company GuardianBlue Early Warning System). The TOC Analyzer is a key component of GuardianBlue, providing increased sensitivity to organic contaminants.
Whenever the Event Monitor enters triggering mode, it immediately signals the Automatic Sampler to begin capturing a real-time water sample. This allows water utilities to conduct additional forensic analysis on actual water samples as part of an emergency response plan.
Historically, monitoring of operational parameters in distribution systems has been conducted in a piecemeal and disorganized manner. For the GuardianBlue Event Detection System to have its intended impact as a deterrent, it is important to understand that the distribution system represents the last logical frontier in the water quality field (Roberson and Morley). With this system in place, potential attackers would recognize that monitoring of source water and treatment plant processes has advanced to a level at which the U.S. Department of Homeland Security can be confident that safe drinking water is being delivered (Bennett). Attackers would also know that once water enters aging distribution systems, knowledge of its ongoing reliability has historically been limited by the quality and quantity of available data.
Potential attackers would find that much of the monitoring in distribution systems has previously relied on sporadic grab samples tested for a few narrow parameters, or the occasional regulatory testing required by rules such as the Total Coliform Rule. However, since 9/11, the adoption of the GuardianBlue Event Detection System has significantly improved this situation. Numerous communities have installed multi-parameter monitoring stations throughout their distribution systems as early warning systems based on potential water security threats (Vary). These continuous online systems have recorded — and continue to record — large volumes of data relevant to water quality in the distribution systems where they have been deployed.
The GuardianBlue system has a number of notable strengths and some limitations. One strength is its installation flexibility: it can be mounted on the floor or on a wall. Wall mounting requires approximately 10 feet wide by 5 feet high, with the auto sampler extending roughly 3 feet from the wall. Floor installation is equally straightforward and simply requires a slightly larger footprint.
Water distribution systems can also be vulnerable to accidental exposure to undesirable water quality events. In one real-world example, a water utility was forced to revert to operating an older water treatment plant while maintenance was performed on a newer one. A pump responsible for dosing fluoride into the treated water failed, causing the dose to increase over time. When the overfeed occurred, the GuardianBlue Early Warning System not only triggered an alarm but also identified the probable cause as a fluoride overfeed. This allowed a rapid response before customers were exposed to potentially hazardous levels of fluoride. While fluoride is beneficial for dental health at low doses, it can be harmful at moderate to high concentrations. The commonly recommended intake of fluoride is 1 mg per day.
Another strength of the GuardianBlue system is its ability to provide warnings well in advance of serious infrastructure failures. In one documented instance, the GuardianBlue system issued an alarm nearly three full days before a catastrophic pipe burst. Using its distinctive algorithm and frequently monitored parameters, GuardianBlue detected simultaneous changes in both conductivity and chlorine levels. These variations are generally subtle enough to escape human notice, but the algorithm identified the anomaly and continued alerting operators approximately 70 hours before a 36-inch main broke, releasing millions of gallons of water into a downtown area. Investigation revealed that a small crack in the pipe had altered conductivity and chlorine readings due to reduced water age. About three days later, the catastrophic break occurred. The monitoring station was located 2 miles upstream from where the break happened. The utility was able to name this event in the Plant Library so that, should a similar pattern be detected in the future, the Event Monitor would recognize and flag it. The EPA has estimated that the average pipe break costs approximately $28 million in repairs and lost revenue.
A further strength of the GuardianBlue Event Detection System is its reliability. In one case, a drinking water facility on a military base was receiving persistent customer complaints about unusual taste and odor. Each time a complaint was received, plant staff would travel to a sampling location in the distribution system and test the water, but repeated attempts failed to identify the cause. After installing the GuardianBlue Event Detection System, the facility was able to monitor water quality on a continuous basis and successfully correlate poor water quality readings with the complaints (Bush). The investigation revealed low-flow areas and dead ends within the distribution system. Armed with this information, plant operators improved their flushing schedule and significantly enhanced water quality, resulting in no further complaints.
One weakness of the system involves its alarm testing capabilities. Agent alarms cannot be systematically tested in the field because the agent list is proprietary and the actual agents are hazardous to handle. Third-party testing using thirteen specific agents has been conducted by the EPA and Battelle as part of an Environmental Technology Verification study. The results of these studies confirm that GuardianBlue is capable of accurately classifying agents.
"ROI justification and cost-offset strategies"
"Utility staff response and integrated monitoring benefits"
"Strong endorsement for broad system deployment"
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