The Department of Public Works is meeting regularly with the Tompkins County Health Department to discuss the ongoing water discoloration issue, as well as follow up testing for City owned plumbing fixtures that had lead detected above the Action Level of 15 ppb.
The persistent water discoloration is in large part caused by the lack of rainfall this summer. The area creeks are showing the lowest flows on record, and the small flow from Six-Mile Creek into the City reservoir is coming mostly from groundwater. Groundwater in the Six-Mile Creek watershed contains higher amounts of iron and manganese than normal surface water runoff, so the water treatment plant is modifying its processes to respond to these different characteristics of the source water. Iron and manganese are the primary cause of water discoloration, and are being measured in the source water at levels nearly three times higher than the treatment plant normally receives.
The City is adding sodium permanganate at the raw water intake to the treatment plant to oxidize and precipitate iron and manganese out of the water in the early treatment processes. So far, this has been very effective and has eliminated nearly all of the iron and most of the manganese out of the finished water. The treatment plant has also been increasing the amount of corrosion inhibitor in the finished water to help reduce rust from mobilizing within the distribution pipes, made worse by warmer water temperatures. Finally, the City continues to flush fire hydrants in neighborhoods with discolored water. There are still areas of the city that are showing persistent problems, but all indications are that conditions are improving.
Drinking water tests for chlorine and bacteria counts throughout the distribution system have been normal, indicating that the discoloration is not affecting our disinfection processes.
For residents in the Southside and Titus Flats neighborhoods, the water turned much darker on July 19th due to early morning testing of the fire pumps at Titus Towers. These mandatory fire safety tests generate much higher flows than normal, and the higher velocity of the water in the water mains stirs up sediments and carries them to people’s homes. This effect is unfortunately more pronounced when the water is warmer, as it is now. Water and Sewer crews were out flushing the water in the neighborhood after the test until the stirred-up sediment was cleared from the system at around 2:00 p.m.
The Tompkins County Health Department is currently reviewing a plan to retest the plumbing fixtures at Cass and Stewart Parks and other City facilities that showed lead concentrations above the Action Level of 15 ppb. In the meantime, these fixtures have been shut off and/or labeled to prevent human consumption, and will remain shut down until the cause has been identified and fixed. The drinking fountains that are still operating at the parks are those that originally tested below 15 ppb.
A Water Conservation Advisory has been issued by the Tompkins County Health Department. The City of Ithaca is also asking its water customers to voluntarily conserve water use during this period of severe drought in the region. More information on the drought conditions can be found at: