Most of the attention on lead has been focused on its effects on children. Nationally, more than 2.4 million children are at risk nationally from potentially high lead levels, nearly 250,000 children are exposed to lead levels high enough to impair their intellectual development, and as many as 70,000 children below age 5 have high lead levels in their blood. Lead usually makes its way into water supplies by corrosion of parts of the plumbing system such as lead pipes, solder, and fixtures. Both very old and very new homes pose the greatest lead threats. Many old homes were built with lead fixtures, while some new homes have not yet developed mineral coatings inside pipes that prevent lead contamination.
Hot water is likely to contain higher lead levels.
As a result, many experts advise flushing the system for a few minutes or using cold water when preparing baby formula. Even though replacement of lead lined fountains is taking place in many Texas schools, that step may not eliminate an area's lead problem. Officials in Round Rock reported lead levels in their drinking water at concentrations near EPA limits even after coolers were replaced. Radon is a naturally occurring element that is dissolved in groundwater and released when the water is agitated and heated from running water. The radon can then be inhaled and can lead to lung cancer.