Latest information for Amston Lake water system customers
The Amston Lake water system serves 181 year round and approximately 170 seasonal customers in Hebron, Lebanon and Colchester
Written Notice mailed on April 16, 2012
Connecticut Department of Public Health - Amston Lake fact sheet
Connecticut Water - Amston Lake Summary
Last updated: May 15, 2012
Water samples are still being collected twice per week from 10 homes in the Amston Lake water system. The frequency and location of the samples were approved by Connecticut Department of Public Health (DPH) as being representative of the system. Since January 20, all 325 water samples collected have tested below the Action Level for copper. The most recent results from Tuesday, May 15, showed the average level of copper detected was 0.11 mg/L, far below the Action Level of 1.3 mg/L.
Since the water samples from these 10 homes are collected by customers we depend on them to provide the samples. Occasionally, a customer may not be able to provide a sample and that is why on the summary of copper test results at www.ctwater.com, you may see dates where less than 10 samples have been tested. Also, we continue to collect samples from customers upon request, which is why some dates have more than 10 samples.
Health effects
The DPH has stated in its Amston Lake fact sheet, which was distributed at last month’s Public Availability Session that based on their review of the specifics at Amston Lake that:
- Copper levels in the Amston Lake water system were not high enough to cause liver or kidney damage or any other permanent health effects.
- Historic data indicates that copper concentrations in the drinking water were high for only a relatively short period of time.
- No medical monitoring is recommended for Amston Lake customers.
The DPH Amston Lake fact sheet is also available by request to 1-800-286-5700.
Flushing activities
We continue to do flushing to move the water and maintain the desired pH levels throughout the system. We have received inquiries from customers asking if there are any impacts to Amston Lake from these flushing activities.
Connecticut Water is committed to protecting the environment and minimizing any potential impacts on land, water and air from our operations. We have taken steps, using best management practices, to reduce any impact on the lake.
- Dechlorinating (removing the chlorine) from the water as part of our flushing operations.
- Discharging water from flushing operations as far away from the lake as possible to allow for natural absorption and filtration through the soils.
Even during the period when elevated copper levels were experienced by homeowners, the level of copper in our distribution system was very low, often below the detection limit so discharges from our operations would not have had elevated copper levels.
A copy of the data sheet for Potassium Hydroxide, the treatment additive used to increase the pH, was provided to the Amston Lake District Board.
Consultant’s Report
We have received the final report from Matco Services. As you recall, Matco had requested pipe and water samples to determine whether it was electricity or water chemistry causing the elevated copper levels. The analysis of the pipe samples allowed Matco to conclude that it was not electricity but that the pH of the source water at the wells had dropped, or became more acidic, which led to the water becoming more corrosive. The pipe samples were taken solely for that aspect of the investigation and there will not be any additional pipe samples collected or analyzed.
Matco was not able to identify the precise cause of the recent drop in pH, but states in its report that it is likely related to natural hydrologic or meteoroligical events. Regardless of the cuase of drop in pH, we are able to effectively treat the water by increasing the pH of the water entering the distribution system. With the treatment in place, the pH of the water delivered to customers is maintained, even if the levels at the source should change again.
We are monitoring pH levels on a daily basis, as required by the DPH, and can effectively adjust our pH treatment to maintain pH in an optimal range when it is delivered to customers’ homes. Maintaining the proper pH has proven to be very effective in treating the copper issue. Customers can have confidence in the water quality now that treatment is in place, as evidenced by the fact that all samples (more than 300) tested from customers’ homes since January 20th have been below the Action Level of 1.3 mg/L.
Future communications
Connecticut Water will continue to update you weekly with reverse 911 calls and a written notice with a summary of the week’s copper test results and other important information. For ease and efficiency, we are planning to mail the notices going forward, unless the information requires more immediate notification. Also, we will use the reverse 911 calls if immediate notification is required.
We encourage you to contact Connecticut Water directly if you have questions about water system operations, if you would like your water tested for copper, or if you would like the latest copper results and are not able to access our web site. Connecticut Water can be reached at 1-800-286-5700 or by e-mail by clicking the Contact Us link on our Web site at www.ctwater.com.
If you have questions about drinking water quality standards and regulations please contact the DPH’s Drinking Water Section at (860) 509-7333.
If you have questions about the health effects of copper at the Amston Lake water system please call DPH’s Environmental Health Section at (860) 509-7748, or consult with your physician.
Copper test results for First Draw samples collected since January 19, 2012
Date |
Number of Samples |
Average Copper Level |
Highest Copper |
Number Above Action Level* |
Average pH |
Lowest pH |
5/15 |
9 |
0.11 mg/L |
0.24 mg/L |
0 |
8.34 |
8.16 |
5/10 |
8 |
0.16 mg/L |
0.34 mg/L |
0 |
8.21 |
7.96 |
5/8 |
8 |
0.14 mg/L |
0.48 mg/L |
0 |
8.28 |
8.00 |
5/3 |
9 |
0.18 mg/L |
0.54 mg/L |
0 |
8.27 |
7.80 |
5/1 |
10 |
0.13 mg/L |
0.39 mg/L |
0 |
8.34 |
7.88 |
4/26 |
10(F) |
0.13 mg/L |
0.39 mg/L |
0 |
8.42 |
8.03 |
4/24 |
9 |
0.11 mg/L |
0.18 mg/L |
0 |
8.45 |
8.14 |
4/19 |
9 |
0.29 mg/L |
1.25 mg/L(E) |
0 |
8.32 |
8.04 |
4/17 |
7(D) |
0.18 mg/L |
0.61 mg/L |
0 |
8.27 |
8.10 |
4/12 |
7 |
0.18 mg/L |
0.32 mg/L |
0 |
8.30 |
8.03 |
4/10 |
8 |
0.11 mg/L |
0.32 mg/L |
0 |
8.28 |
7.98 |
4/5 |
8 |
0.17 mg/L |
0.27 mg/L |
0 |
8.21 |
8.07 |
4/3 |
9 |
0.19 mg/L |
0.36 mg/L |
0 |
8.19 |
7.94 |
3/29 |
9 |
0.09 mg/L |
0.20 mg/L |
0 |
8.32 |
8.12 |
3/27 |
9 |
0.16 mg/L |
0.36 mg/L |
0 |
8.30 |
8.11 |
3/22 |
9(C) |
0.17 mg/L |
0.29 mg/L |
0 |
8.34 |
8.24 |
3/20 |
10 |
0.10 mg/L |
0.19 mg/L |
0 |
8.42 |
8.3 |
3/15 |
10 |
0.13 mg/L |
0.34 mg/L |
0 |
8.41 |
8.24 |
3/13 |
10 |
0.12 mg/L |
0.31 mg/L |
0 |
8.37 |
8.15 |
3/8 |
9 |
0.23 mg/L |
0.45 mg/L |
0 |
8.26 |
7.81 |
3/6 |
10(B) |
0.18 mg/L |
0.40 mg/L |
0 |
8.32 |
8.05 |
3/1 |
9 |
0.21 mg/L |
0.46 mg/L |
0 |
8.24 |
7.97 |
2/28 |
12 |
0.15 mg/L |
0.40 mg/L |
0 |
8.37 |
7.88 |
2/23 |
12 |
0.29 mg/L |
0.70 mg/L |
0 |
8.15 |
7.38 |
2/21 |
15 |
0.18 mg/L |
0.44 mg/L |
0 |
8.22 |
7.86 |
2/16 |
10 |
0.28 mg/L |
0.50 mg/L |
0 |
8.14 |
7.90 |
2/14 |
9 |
0.30 mg/L |
0.59 mg/L |
0 |
8.06 |
7.86 |
2/9 |
10 |
0.30 mg/L |
0.71 mg/L |
0 |
8.04 |
7.66 |
2/7 |
9 |
0.34 mg/L |
0.75 mg/L |
0 |
8.11 |
6.54 |
2/2 |
11 |
0.33 mg/L |
0.83 mg/L |
0 |
8.01 |
7.64 |
1/31 |
12 |
0.34 mg/L |
0.65 mg/L |
0 |
8.08 |
7.52 |
1/26 |
10 |
0.313 mg/L |
0.67 mg/L |
0 |
8.02 |
7.68 |
1/24 |
10 |
0.332 mg/L |
0.75 mg/L |
0 |
7.82 |
7.36 |
1/22 |
2 |
0.52 mg/L |
0.54 mg/L |
0 |
7.41 |
7.38 |
1/21 |
3 |
0.42 mg/L |
0.52 mg/L |
0 |
7.43 |
7.35 |
1/19 |
8 |
0.59 mg/L |
1.92 mg/L |
2(A) |
7.58 |
7.17 |
* the Action Level for copper is 1.3 mg/L.
(A) The two samples that came back above the Action Level on 1/19 were resampled on 1/21 and 1/22 and resamples results on both days were below the Action Level.
(B) Two samples were collected by customers on 3/6, but were not left out in time for the morning pick up. These samples were picked up on Thursday, March 8.
(C) One sample was collected by a customer on 3/22, but was not left out in time for the morning pick up. This sample was picked up on 3/27.
(D) Two samples collected on 4/17 were dated 4/3 and 4/5 respectively were not included included in the test results in the table for 4/17. Both samples were below the Action Level and the average copper level was 0.09 mg/L.
(E) One sample collected on 4/19 was significantly higher then all other samples and showed unusually high turbidity and color that was not seen in other samples collected that day, including those itaken n close proximity. Connecticut Water, the lab, and DPH are investigating to see if there is something unusual about this site or sample collection that would give a high reading.
(F) One sample collected on 5/3 was dated 4/26. The results for this sample have been added to the 4/26 results row.
Results for 1/6/12 through 1/19/12 are available here.
Public Availability Session
Customers of approximately 25 homes served by the Amston Lake water system attended the Public Availability Session on Thursday, February 16, 2012, and the majority indicated they found it to be helpful. At the Session copies of the Connecticut Department of Public Health's Amston Lake fact sheet and Connecticut Water's Amston Lake summary available. Both documents can be viewed here:
Connecticut Department of Public Health - Amston Lake fact sheet
Connecticut Water - Amston Lake Summary
One of the most commonly asked questions by the people who attended was: “How do I know that my water is safe and we will not have elevated copper levels in the future?”
We know that elevated copper levels experienced throughout the system were caused by water chemistry at the source wells and were not the result of stray electrical current affecting the entire system. Specifically, a recent drop in the pH at the source wells has been identified as the problem. The underlying cause of the recent drop in the pH of the source water has not been determined, but we are able to effectively treat the water by adjusting pH at the source wells.
Correcting low pH at the source wells is done by adding a treatment chemical that increases the pH of the water as it enters the distribution system. Once pH treatment has been implemented, we are required by the DPH to regularly monitor pH levels on a daily basis. We do this using pH analyzers and chart recorders. The pH analyzers continuously monitor the pH of the water going into the distribution system and alert our people via alarm system 24 / 7 if the pH goes above or below a set range. The chart recorder continuously records the pH of the water going into the system so that we can track pH data continuously going forward.
In the future, as the pH of the source water changes, we are able to adjust the amount of treatment chemical added to keep the water’s pH in an effective range. For example, if the pH at the wells were to drop to 5, we would be able to maintain a pH in the effective range by increasing the amount of treatment chemical added. The opposite is also true, if the source water pH were to increase, as it has done recently between mid-January and mid-February, then we are able to reduce the amount of treatment chemical.
Also, the type of treatment chemical used and the method for adding it to the water system requires approval from DPH. The DPH inspected and approved our chemical feed system and the treatment chemical (potassium hydroxide) that is being used before we implemented the pH adjustment. Any future change in the feed system or the treatment chemical would require approval by DPH.