Re:Hacker increased chemical level at Oldsmar's city water s...
by jcranmer on Tuesday February 09, 2021 @01:23AM
(#26074489)
Your understanding is incorrect.
It depends on what contaminant you are measuring, but the testing frequency can vary from "every several years" to "continuously monitored and sets off a SCADA alarm if it exceeds a given threshold." The biggies--IIRC, turbidity, pH, and dosages of coagulant and treatment chemicals--are logged every 15 minutes, with more tests happening on hourly 6-hourly, and daily frequencies, followed by yet more contaminants happening largely on monthly or quarterly assessment bases. The issue in question would have shown up in a pH measurement, so there's no reason it shouldn't have been caught within minutes.
It depends on what contaminant you are measuring, but the testing frequency can vary from "every several years" to "continuously monitored and sets off a SCADA alarm if it exceeds a given threshold." The biggies--IIRC, turbidity, pH, and dosages of coagulant and treatment chemicals--are logged every 15 minutes, with more tests happening on hourly 6-hourly, and daily frequencies, followed by yet more contaminants happening largely on monthly or quarterly assessment bases. The issue in question would have shown up in a pH measurement, so there's no reason it shouldn't have been caught within minutes.