3Ts: TRAINING, TESTING, TAKING ACTION
TAKING
ACTION
Module 6: Remediation and Establishing Routine Practices
Follow-Up Sampling

Follow-Up Sampling
Once a remediation option has been selected and implemented, there are additional follow-up
procedures that should be taken. Work with plumbers and maintenance staff to ensure that additional
samples are taken from any outlets that were impacted by replacement of fixtures, reconfiguration of
plumbing, or other remediation actions.
A comparison of original and additional samples will help to
assess whether the remediation has been successful in
reducing lead in drinking water. Additional samples may be
required to further pinpoint sources of lead contamination, if
lead levels are still elevated.
Follow-up sampling when flushing is being used
If flushing is selected as a remedy, follow-up testing procedures should include sampling to verify the
effectiveness of flushing procedures at each problem outlet. If the 30-second flush sample (in Step 2) is low,
flushing for 30 seconds may be sufficient. In other cases, a longer flushing duration may need to be
determined. See the Flushing Best Practices factsheet for additional information on outlet flushing
instructions.
After determining the required flushing duration, repeat sampling should be collected after flushing, followed
by a period of normal water use at the fixture, to determine whether flushing daily, twice daily, or at a
different frequency is needed to ensure lead levels remain low throughout each day. For determining if once-
daily flushing is sufficient, flush the outlet at the routine time and duration (e.g., 30 seconds) and then collect
one 250-rnL sample near the end of the day (e.g., after 10 hours of representative water usage following
morning flushing). If the sample collected at the end of the day contains high levels of lead, more frequent
flushing (e.g., every 4 hours or every time the outlet is used) or a different remedy should be evaluated.
v>EPA
OFFICE OF GROUND WATER
AND DRINKING WATER
Office of Water
EPA 815-F-18-026
October 2018
Ensure that additional samples are taken before a facility opens and before any water is used. Additional
samples should follow the same testing process as the initial samples. Sample any replaced or reconfigured
components using the recommended procedures for first-draw
and/or flush samples. Be sure to document (e.g., in sample
labeling) the conditions that follow-up samples were collected,
such as after fixture replacement or after POIJ installation.

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