There is a lot in the news these days concerning lead in drinking water, and whether or not public water systems are being kept safe from this deadly contaminant. There have been high profile failures documented in some systems and current practices are being questioned in others.
As a customer of the Columbus City Utilities, you should be fully aware that your water is safe and exceeds all the requirements set forth by the U.S. Environmental Protection Agency (USEPA) and the Indiana Department of Environmental Management (IDEM), and that these results were obtained using accurate and approved sampling and testing procedures.
For lead to be present in drinking water, there have to be two conditions met. Lead has to be present and available somewhere within the plumbing and the water had to have the proper chemistry to draw the metal out of the piping.
Lead has been used in water pipe for a very long time. (We’re not going to go into just how long, but if you’re interested, click here.) In the United States, and specifically in Columbus, lead has not been used in construction for many years.
The primary use of lead in the local public system has been in the use of a “lead gooseneck” as a component of the water service. In older service lines, the straight section from the meter pit to the main was made of iron galvanized piping. The final two feet between the service line and the tap onto the public water main was, typically, a short section of lead pipe curved into place. The malleability of the lead provided flexibility to the service line and prevented fractures and leaks due to expansion and contraction during seasonal temperature changes.
By 1955, Columbus had quit using lead in its water service lines. Any home constructed or connected after 1955 is not at risk from lead contamination coming from the water service.
The Columbus City Utilities replaces over 100 water service lines every year, for various reasons. Most of these are the older type. So, even if your home has been connected to the water system since before 1955, the odds are pretty good that the service line has already been replaced since its original installation.
However, water service lines are not the only source of lead in water systems. Copper plumbing has been a very popular construction material in residential homes since the late 1950’s. These pipe sections were joined together using solder that was an alloy of lead and tin prior to 1978. After 1986, lead free solder was required to be used in all drinking water systems.
Let’s assume you have a house connected to City water prior to 1955 or you have a somewhat newer home, but it’s older than 1978 and it has copper plumbing. Are you drinking toxic lead?
Not likely. For lead to leach out of piping, the water that comes into contact with it must be “aggressive”. That means it must have chemical characteristics (i.e. low pH) that draw metallic particles out of the pipe and into the drinking water.
Columbus water is pH neutral to slightly alkaline (higher pH). In its natural form it doesn’t dissolve piping, it tends to plate it. To further protect against corrosion, the treatment process utilized includes the introduction of a small quantity of polyphosphate that acts to further coat piping and protect against corrosion.
Beyond what we know about the piping in Columbus and the chemistry of the water, we test the water in people’s homes on a regular basis to ensure its safety. The Indiana Department of Environmental Management and the USEPA have requirements that all public water systems must follow regarding the regular testing of water customers for high levels of lead (and/or copper). (IDEM lead and copper rule; USEPA Lead and Copper Rule)
Every three years, Columbus is required to test water from 30 homes for lead and copper. The water must be collected from water faucets inside the home and the water must have been in contact with the plumbing for at least six hours (no flushing, before sampling). If more than 10% of those homes tested produce concentrations above 0.015 milligrams per liter, we would be required to take corrective actions that would include public announcements and education of the risks involved. Columbus has always met these requirements.
We constantly monitor the pH of the water leaving our treatment facilities. In addition, we test at locations within our distribution system to see if the water has become corrosive in transit. All tests continue to confirm that Columbus water is not aggressive in nature.
Not quite. As long as lead exists in the distribution system, the risk is still there (albeit a small one) for lead to leach out some day and enter the drinking water. Of the 15,000 accounts currently served but the Columbus City Utilities, we estimate that 1,000 to 2,000 still have a component of lead in the water service line. We are currently committed to conducting a full inventory of the water distribution system to locate and log each old style service line in the system, and to adopt a program for their timely and total replacement.
The three year testing cycle approved by IDEM for our system is based upon the fact that we have had such good and consistent results in prior years. To maintain our customers’ confidence in the quality of our water, we are conducting an “off-schedule” series of tests. In addition, we can perform screenings for customers upon request that, although not a substitute for certified testing, can provide assurances that lead is not present.