Water that leaves the Ames Water Treatment Plant does not contain lead. However, once the water interacts with private water systems, lead can leach out of older pipes and lead-based solders at pipe joints, especially when pipes become corroded. Once a lead service line corrodes, the lead may then get into a home drinking water supply.
The City of Ames water utility has been treating water to control corrosion for decades. Even homes with lead pipes have built up a preventative coating inside pipes forming a protective barrier between any metal in the plumbing and the water.
Lead levels in drinking water depend on the chemistry of the water supply. Corrosion is more likely if the water has a low pH (is acidic) or if the alkalinity is too low (pH in water cannot be stabilized). The pH and alkalinity, among many other factors in managing the water chemistry, are controlled by the Ames Water Treatment Plant operators who are on duty 24 hours a day.
Even with all the City does to protect drinking water, residents can still be exposed to higher lead levels from stagnant water that sits in a home’s lead pipes. If water in the pipes is not used for several hours or days (such as overnight, during the work day, or while on a vacation) lead levels can increase in the water for those who have lead service lines.
Since lead and copper are regulated, the City is required to control the corrosiveness of our water. The pH and alkalinity of Ames water is maintained at a level which helps build a protective coating on the inside of pipes so lead and copper cannot leach into the water. Once this thin coating forms, there is a protective barrier between any metal in the plumbing and the water.
The U.S. Environmental Protection Agency requires the City to monitor the drinking water in the distribution system for lead and copper. Every three years, the Water & Pollution Control Laboratory tests targeted residences (homes known to possess lead service lines or that have copper plumbing/lead solder) for lead and copper levels.
Of all of the samples taken, at least 90% must be less than 15 micrograms of lead per liter of water. The City of Ames water has never exceeded this action level. The results of the lead and copper testing are submitted at the state level to the Iowa Department of Natural Resources.
A report is sent to the residents informing them of the results for their homes. The results are also published in our annual Consumer Confidence Report.