Is partial lead service line replacement helpful or harmful?

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In 1991, the Environmental Protection Agency published the Lead and Copper rule. There was clear evidence at the time that both copper and lead in drinking water caused health problems.

So what did the rule actually state? Essentially, the EPA stated samples had to be taken directly from customer’s tap water. If lead concentrations rose above 15 parts per billion, or copper at 1.3 parts per million in more than 10% of the samples, the public water system had to take direct actions to control corrosion. If lead was above the 15 ppb, the system is also required to notify the public.

The Lead and Copper rule has not sat stagnant. Since its creation, there have been several amendments and additions to the rule. Since 2011, the EPA has been reviewing the effectiveness of partial lead service line replacements. (If lead in water does not decrease after corrosion control treatments, partial line replacement is often a last resort.) Interestingly, this method of decreasing lead in water may actually increase lead for several months – or longer.

“The SAB [Science Advisory Board] found the available information is broadly suggestive that PLSLR may pose a risk to the population, due to the short-term elevations in drinking water lead concentrations.”

Unfortunately, the studies done have been limited in time. (The evidence suggests that the reason lead levels are heightened after partial replacement is due to galvanic corrosion.) It’s been suggested, such as in Flint, that flushing water through the taps could alleviate the levels of lead after partial line replacement, but it’s not a guarantee.

So what’s the correct “fix” in this situation if partial service line replacements actually lead to harm, not good? EPA is looking into a better answer than what is currently available. Currently, the EPA is reviewing expert peer candidates that would review a lead modeling report – a promising step in the right direction.

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