Today's question: What would happen if somebody intentionally put a dangerous chemical in our water?
"Plain Talk" answer: Because water utilities are aware of the potential for malevolent attacks on water supplies, most have increased their monitoring and testing of water quality as a result of possible threats. This means that if something strange was added to the water, the water quality parameters, such as pH levels, flow and turbidity (the amount of suspended particles in water), would noticeably change and water system operators would be alerted during routine testing or through automated devices that constantly measure these parameters. The operators would then conduct more testing to determine what the added substance was and take precautions to prevent the contamination from becoming a problem at the tap.
If the contamination had already reached the distribution system, the water system would alert the end-users through public notification systems and possibly issue do-not-use or boil-water orders. The utility would then have to decontaminate the system, which would require shutting down the distribution system while it is cleaned and disinfected. In that case, the utility would provide consumers with bottled water or distribute clean water from trucks called water buffaloes.
For more information on this and many other water-related topics, check out "Plain Talk About Drinking Water" by Dr. James M. Symons.