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Public Notice – Important Information About Your Drinking Water

Mount Vernon Board of Water Supply




Treatment Technique Requirement Was Not Met


Our Water System recently violated a drinking water requirement. Although this is not an emergency, as our customers, you have a right to know what happened, what you should do and what was done to correct this situation.

During Hurricane Sandy, for a period of approximately 1½ hours during the late evening of October 29, 2012 and early morning hours of October 30th, the turbidity from the New York City (NYC) Water System (our source of water), exceeded the 5 Nephelometric Turbidity Unit (NTU) Maximum Turbidity Treatment Technique Performance Standard for Surface Water Systems operating under Filtration Avoidance. Normal turbidity levels on our source water are Less Than 1 NTU. Monitoring samples collected during this event showed levels of 6.6 NTU from the NYC Water system at our Entry Point. Turbidity, a measure of water clarity, has no health effects; its source is soil runoff. However, elevated turbidity can interfere with disinfection and provide a medium for microbial growth. Although subsequent monitoring indicated this elevated turbidity only lasted approximately 1½ hours, turbidity may indicate the presence of disease-causing organisms.


What was done to correct the situation?

The NYC Water System implemented operational changes the night of October 29th to reduce their elevated source water turbidity levels. Water sampling performed the morning of October 30th indicated that all Entry Point turbidity

levels returned back into compliance, below the 5 NTU level, after approximately 1½ hours. Throughout the event, personnel closely monitored the source water chlorine residuals coming in from NYC Water System to ensure that the Contact Time Inactivation Ratio for the inactivation of Giardia lamblia cysts and viruses was satisfactorily achieved before the water reached our 1st customer. As a precautionary measure, Entry Point disinfectant (chlorine) residuals were increased to enhance the effectiveness of disinfection. In addition, the NYC Department of Environmental Protection has reported that all the source water provided us during this event was also treated with UV light, which provided a secondary level of disinfection against potentially harmful microbiological contaminants such as Cryptosporidium and Giardia. Finally, routine water quality sampling following this event have not detected the presence of disease-causing organisms.


What does this mean?

This is not an emergency. If it had been, you would have been notified within 24 hours. This incident constitutes a treatment technique violation as specified in the Code of Federal Regulation (40CFR§141.71(c) (2)(i) and the New York State Sanitary Code Part 5, Subpart 5-1, Section 5-1.30(c) (2). The State has determined that this violation was not a public health hazard but does require Public Notification.


What should I do?

There is nothing you need to do. You do not need to boil your water or take other actions. We do not know of any contamination and none of our testing conducted throughout our Water System following this event has shown disease-causing organisms in the drinking water. However, State and Federal drinking water regulations require public notification that includes the following language: If you have a severely compromised immune system, have an infant, are pregnant, or are elderly, you may be at increased risk and should seek the advice from your health care provider about drinking this water. General guidelines on ways to lessen the risk of infection by microbes are available from EPA’s Safe Drinking Water Hotline at 1-800-426-4791. These microbes include bacteria, viruses and parasites which can cause symptoms such as nausea, cramps, diarrhea and associated headaches. Note, these symptoms are not caused only by microbes in drinking water. If you experience any of these symptoms and they persist, you may want to seek medical advice.

For more information, please contact the Board of Water Supply at (914) 668-7820. Landlords and businesses please share this information with other users at this location. This notice is being sent to you by the Mount Vernon Board of Water Supply, NY State Water System ID#5903441. Date of Notice January 31, 2013.

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