Lead and copper have the potential to be dissolved in water but only if the conditions are conducive to such. Lead and copper are not present in the source of water. The can only enter the water supply if they are part of the plumbing system that conveys water to your house.
In order for lead or copper to leach into the water in the pipes, there must be older pipes that use lead solder or copper pipes that are commonly used. In addition, the water must be of a nature that will allow for the lead and or copper to be dissolved into the water. The amount of time water sits in contact with the pipes has an influence on the possible leaching of the lead and/or copper.
In order to minimize the probability of lead and or copper to enter the water, treatment is performed at the water plants to reduce any natural tendencies of the water to leach out the lead and copper.
The District is required to do extensive testing of the water supply to ensure the levels of lead and copper are below federal and state standards. The results of the testing have always and continuously indicated the levels of lead and copper are in compliance.
One way a homeowner can further ensure there is no lead or copper in their tap water is to flush the tap before filling up a drinking glass. By flushing the water for a few minutes to remove the first slug of water that may have been in contact with lead plumbing.