Northern Westchester Joint Water Works Lead & Copper Compliance
| TO: | Northern Westchester Joint Water Work’s Board of Trustees (via email) |
| FROM: | Matthew Geho, Operations Director |
| RE: | NWJWW Lead and Copper Compliance |
| CC: | Catherine Paget, Tom Wood, Ray Reber (via email) |
| DATE: | February 1, 2016 |
As you are aware, Flint Michigan is experiencing a water quality issue (elevated levels of lead and copper) that has been making both National and International news. The elevated lead levels in the public drinking water was caused by a change in source water, which was not properly treated and monitored. The intent of this memo is to provide the members of Northern Westchester Joint Water Works (NWJWW) with information about their lead and copper levels, the monitoring program we are mandated (New York State Department of Health-NYSDOH) to follow, and compliance reporting.
All members of the NWJWW are on a reduced monitoring frequency for compliance monitoring, which is every three (3) years. This reduced monitoring is the result of multiple sampling events reported to the NYSDOH, in which there was no exceedance of either the lead or copper action limits. Compliance is determined by calculating the 90th percentile for all samples collected during the assigned sampling event. In summary, the data collected is compiled in descending order, and the total number of samples collected is multiplied by 0.9 (90%). This number represents the total number of sample sites that can exceed the lead and copper action limits. For example, if 30 samples are collected 27 of them must be at or below the action limits (lead is 15 ug/l and copper is 1300 ug/l*).
- * ug/l – microgram per liter or part per billion. 1 ug/l of lead would equate to 1 part of lead in 1 billion parts of water. This is 1/1000th of a mg/l or part per million
Steps are taken at both NWJWW’s treatment plants to ensure lead and copper levels remain below federal action limits. These steps include 1) utilization of high quality source water 2) addition of corrosion control inhibitors (Phosphoric acid), and pH adjustment (sodium hydroxide) to minimize the corrosiveness of the water.
The data, as reported to the NYSDOH, for each member’s latest compliance monitoring is listed below:
| System | Date | # of Samples | Lead (ug/l) | Copper (ug/l) |
|---|---|---|---|---|
| Somers Amawalk Heights** | 2013 | 5 | 2.4 | 91.25 |
| Somers Shenorock** | 2014 | 10 | 3.8 | 387 |
| Somers Windsor Farms** | 2015 | 5 | 3.8 | 123 |
| Yorktown Consolidated Water** | 2014 | 30 | 2.2 | 210 |
| Cortlandt Consolidated Water** | 2015 | 30 | 3.0 | 90 |
| Montrose Improvement District** | 2014 | 10 | 1.3 | 96 |
| Action Limits | 15 | 1300 |
** all members of the NWJWW are in compliance with the testing of lead and copper in the water provided to their communities.
If additional information is requested, please don’t hesitate to direct all inquiries to my office. Office # 914-737-3558 Ext # 111 or [email protected].
