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Frequently Asked Questions - Elevated Chlorine Levels


What happened?

What were the chlorine levels?

What was done to fix this situation?

Why weren't we notified right away? 


What is the standard for chlorine in a drinking water system?
 

What are some of the side effects of consuming water containing levels of chlorine seen during this event?

Why is there chlorine in my drinking water in the first place?

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Q: What happened?
A:  For a few hours on Monday, August 2nd, elevated levels of chlorine were present in a localized southern area of our drinking water distribution system. (see map) The elevated chlorine levels were a result of human error. 

Q:  What were the chlorine levels?
A: Instantaneous results from testing on August 2nd ranged from 2 to 8.6 parts per million between the hours of 5:30 a.m. to 5p.m.



Q:  What was done to fix this situation?
A:  Treatment staff at the Chaparral Plant took immediate action to mitigate the situation and crews began flushing the system as soon as possible.  Other water sources were also mixed into the distribution system to help bring down the chlorine levels.  Chlorine levels began dropping immediately and returned to normal by 5p.m. that day.

We have been working closely with Maricopa County Environmental Services since the situation began and are finalizing an investigative report. 

Corrective actions (protocols and system alarms) are in the process of being implemented to help ensure this type of situation does not occur again.



Q:  Why weren’t we notified right away? 
A:  If there had been a risk to you or your family, you would have been notified immediately. This situation was not an emergency and there was never a threat to your health or safety.

This notification is to inform you about what happened and what we did to correct the situation.  We take the health and safety of our citizens very seriously and immediately began working with Maricopa County Environmental Services Department to assess and correct the situation so that there was not a risk to the public. 

Maricopa County is delegated to enforce Safe Drinking Water Rules for public water systems by the state of Arizona.  We’ve been in constant contact with Maricopa County since this situation began and are working closely with them and following their direction.  Because there is not a health risk associated with short-term exposure to water chlorinated to these levels, we focused our efforts on ensuring the event was as short as possible.



Q: What is the standard for chlorine in a drinking water system?
A:  The standard for chlorine is 4 parts per million (or milligrams per liter) as a running annual average.  This event did not result in a drinking water violation.



Q:  What are some of the side effects of consuming water containing levels of chlorine seen during this event?
A:  Some people who use drinking water containing elevated levels of could experience irritation effects to their eyes and nose.  Ingestion of drinking water containing elevated chlorine could cause stomach discomfort.



Q:  Why is there chlorine in my drinking water in the first place?
A:  Chlorine is the most common form of disinfect for water throughout the world.