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. ------- |