Using backpressure, attackers could launch a relatively widespread attack with similar results, using minimal tools and expertise, according to DHS. The agency says terrorists could use backpressure to intentionally distribute contaminants throughout the public water system, causing an instant public health emergency in addition to leaving a lasting economic and psychological impact.
DHS says police and firefighters should be aware of indicators of a potential backpressure attack. These include vehicles other than fire trucks being hooked up to fire hydrants, signs of tampering with water pipes in commercial buildings, and discolored water, water odors, or decline in water quality. A medical indicator: a burning throat after drinking water.
Dillard says a backpressure attack wouldn't be impossible, but the threat may be overstated because of several redundancies built into the existing water systems to protect from both backpressure and contaminants.
“It’s possible. Virtually any kid taking a high school science class could figure it out, but it would have to be done in such volumes that it would be relatively hard to do because of the fact that we use backflow prevention assemblies in major areas and almost all of your industrial areas,” he said.
If terrorists tried to use a biological agent, Dillard, a tap water enthusiast, said the chlorine in water would most likely take care of it. “That’s what we keep the chlorine for, to keep the nasties out. It also keeps dysentery and cholera out of our water systems."
Dillard said he thinks DHS probably released the bulletin as a reminder to remain vigilant around water systems and utilities infrastructure.
Additionally, all 50 states require controlled cross-connections or backflow prevention systems, and 32 states have active backflow prevention programs. “Our water systems are pretty well protected,” Dillard said.
If a person does notice something suspicious about their water, like strange smells or tastes, they should contact their local water purveyor and ask if there’s been any accident in the area or incidents reported, Dillard said.
Diagram via screenshot of Watts Water Technologies report
Photo by crawfish head/flickr