Important Announcement about Friday Harbor Drinking Water

Trihalomethane (THM) Fact Sheet

During the past year you have been informed that the Town has been unable to fully comply with State mandated changes to the drinking water quality standards. While the Town is in compliance with all other requirements, we regret to inform you that the Town’s water system continues to not meet one of the requirements.

Friday Harbor water users have the right to know about the quality of their drinking water. They should be aware of problems that may cause a concern for immediate or long-term health, what they can do, and what the Town is doing to correct the situation.

The problem we are experiencing continues to be the result of using Chlorine as a disinfectant for our water. Chlorination has made the U. S. water supply safe from illness produced by bacteria, viruses, and parasites; and disinfection has almost completely eliminated risks of deadly waterborne diseases such as typhoid fever, cholera, and dysentery. However, when chlorine has long-term contact with any organic material, such as leaf foliage present in the Trout Lake reservoir, it produces a byproduct known as Trihalomethanes (THMs). THMs include four chemicals: chloroform, bromodichloromethane, dribromochloromethane, and bromoform.

The State of Washington has mandated public water systems check for THMs on a regular basis and that the level of THMs in the water be less than 80 micrograms per liter (ug/L) or 80 parts per billion (previously 100 ug/L).

The fourth quarter sample was measured at 76.2 ug/L; which meets the standard, however the twelve month average level of THMs is 88.23 ug/L, which is still above the maximum allowed. This violation requires that we again notify you that the level of THMs in the water exceeds the State level.

The State has set standards for THMs in water because there is a slight possibility of risks to your health over a lifetime of drinking water with THMs above 80 ug/L. These risks can include problems with the liver, kidneys or central nervous system. The EPA estimates drinking 2 liters of water containing 100 ug/L THMs every day for 70 years could result in 3 extra cases of cancer for every 10,000 people. The slight risk of increased cancer occurs only after decades of drinking water with elevated THMs. There is no immediate risk from the water with THM level above 80 ug/L. If it were, we would have notified you immediately. However, THMs are an important water quality issue faced by all public water systems that rely on a surface water supply.

The Town recently installed electrical power to the Trout Lake Dam. This will allow us to move a portion of our treatment process closer to the source of the high organic material. We have begun an intense series of testing of new products that will help reduce THM levels.

We will continue to work with the State Department of Health exploring alternatives and making adjustments in our treatment process. Our challenge is to find the most efficient and cost effective way of reducing these levels in order to provide you with safe and healthy water.

There are several ways to reduce THMs for drinking water at home. You may wish to filter your drinking water by using activated carbon filters or simply leave your tap water standing in a pitcher in the refrigerator overnight. These simple methods will also help lower THM levels.

If you have any questions regarding THM levels or other water quality related issues, please contact us at (360) 378 – 2810. The Town will continue to keep you informed of our progress.

02/25/2008