Techniques to Control Lead Exposure

from Replacement
As construction activity can release lead into drinking water, steps must be taken to protect consumers during the lead service line (LSL) replacement process. 

​The following flowchart illustrates the three phases of implementing protective measures in the course of planned service line replacement.
Lead service line replacement - Integrating protective measures

Determining how long to flush a structure

Currently, there is not a national best practice for how long to flush a service line immediately after a full LSL replacement, or how long precautionary measures are necessary following replacement. At present, the approach taken at the direction of EPA, states, and individual utilities includes the following steps:
  1. Establish a conservative approach based on available information.
  2. Collect data on lead levels before and after replacement to identify trends in:
    1. How high lead levels are post-replacement.
    2. How long lead levels, if elevated, remain so.
    3. ​What conditions at structures appear to influence lead levels post-replacement?
  3. ​Use the collected data to adjust practice.
Post-construction flushing can introduce debris into home plumbing. 
​Remove aerators on faucets.
Remove point-of-use filtration devices or if they cannot be readily removed, do not flush water through that faucet.
​Flush with cold water only. 
Do NOT use hot water.
​Available data is largely from partial LSL replacements and often from systems that are experiencing difficulty maintaining corrosion control. While lead levels in a home’s water may not be lower initially following replacement of the entire service line due to other existing sources of lead, the service line and replacement process is expected to contribute less lead over time than a partial LSL replacement.
Research is ongoing.  Water Research Foundation is currently supporting “Evaluation of Flushing to Reduce Lead Levels.”  The report is scheduled to be published in 2017.

Clearing the service line by flushing cold water through it removes debris after construction. Clearing the line requires moving water rapidly, which typically involves turning multiple faucets. It is useful to turn on faucets designed for larger flow rates, like bathtubs. Aerators should be removed and cleaned if possible. Flushing in drought-impacted areas or communities who are sensitive to the cost of water, “wasting” water can be difficult to communicate, as can convincing occupants to commit the time requested to completely flush a service line.
The following flowchart illustrates proper protocol for utilities for flushing a service line.
Flushing a Structure

Non-conductive plastic couplings

Non-conductive plastic couplings are used to provide a water tight connection between two pieces of pipe made of different metals without letting the two metal pipes touch. This prevents accelerated corrosion and deterioration in the piping system due to galvanic corrosion and stray current. When replacing an LSL, a connection between copper replacement pipe and residual pieces of lead pipe or galvanized pipe can be made using a non-conductive plastic coupling.  
Warning:
Non-conductive couplings will only work correctly if properly installed.
Warning
If the LSL is replaced with a non-metallic pipe or a non-conductive plastic coupling is used within a few feet of the home, the home owner may need to take additional measures to ensure the structure has sufficient grounding. Historically, connection to the home piping system was used for grounding the home’s electrical system. By removing the underground metal piping, an alternative grounding strategy may be needed. 

​All metal water systems should be “bonded.” Failure to adequately bond the potable water piping systems to the electrical system increases the potential for both fire and electrocution should the piping system become energized (see National Electric Code).