Historically, sabotage to water and wastewater systems has not received much publicity as a viable threat. Safe and sustainable drinking water has been taken for granted. Today, sabotage has to be considered not only as a viable threat, but a plausible one. It is important that cities, counties, provinces, and private companies that own or operate water and wastewater systems consider what weaknesses may exist throughout their systems, what measures should be taken to prevent future acts of sabotage, vandalism, or terrorism, and be ready with a well-tested emergency response plan.

Two types of water system sabotage—vandalism and terrorism—need to be considered. Vandalism interrupts the supply of water and reduces its quantity. Terrorism contaminates the water and reduces its quality. Supply interruptions include the destruction of, or interference with, reservoir dams, water towers or storage facilities, pumping stations, intakes, valves, treatment plants, the distribution system, or fire hydrants, denying the population drinking water or firefighting protection. Supply interruptions can be caused by any number of acts, including physical destruction, interruption of the supervisory control and data acquisition system, or acts that could reduce the water pressure in a system. Supply interruptions can also occur as an indirect result of contamination. As drinking water is essential to human life, denying it for any period could cause panic and disrupt society. Acts of contamination could occur at the reservoir, intake structure, or treatment plants or within the distribution system. Some types of contamination are less effective than others.

With regard to wastewater systems, proximity or access to critical buildings is the main problem. Sewers that run beneath or near airports, critical structures, or federal facilities could allow explosives or other energetics or combustibles to be detonated close enough to create mass destruction. Individual treatment facilities should undertake their own vulnerability assessment, as every facility has different strengths and weaknesses, and then make appropriate modifications to their security systems. Emergency response plans should be updated to reflect the vulnerabilities identified during the assessment. To actively attempt to prevent all possible scenarios of sabotage, vandalism, or terrorism is impossible, but steps can be taken to reduce the chances of future occurrences and to make it as difficult as possible for potential saboteurs to succeed.

To secure water and wastewater systems against these possible threats, security will have to be scrutinized with renewed vigor. Security has to be established to defend against people with many motives, from teenage pranksters vandalizing property to international terrorists bent on mass destruction. When looking at defense of facilities, it is best to look at worst-case scenarios. In defending against saboteurs whose objective is mass destruction, examining the worst-case scenario will capture the lesser motives as well. To defend all water treatment facilities against state-sponsored terrorists whose objective is mass destruction would require resources that are not now available and probably never will be, so it becomes necessary to have a plan to respond to these acts. In general, all resources possible should be used to try to prevent an act of mass destruction. However, plans should be in place to recognize possible problems, delay the problem, and reallocate resources to contain the problem.

The following lists of general, commonsense, and basic security practices are intended to be a general starting point for water and wastewater facilities. These measures are intended for large plants, but some of the measures will apply to smaller systems. The information was gathered from sources such as foreign experts, domestic facilities, the Environmental Protection Agency (EPA) and the Federal Bureau of Investigation (FBI).

The following are general basic security measures to defend water facilities from supply interruptions: