Water Testing
Testing drinking water for lead serves many valuable purposes including:
- Determining effectiveness of corrosion control,
- Evaluating potential exposure,
- Helping communities set priorities,
- Engaging consumers in understanding the issue; and
- Determining compliance with EPA regulations.
Tap sampling can identify homes with lead levels high enough to suggest that further sampling and investigation should be done. However, water testing alone, particularly a single water test, cannot reliably determine if a property has a lead service line (LSL).
The City of Montreal showed success with a method that involved a 30-minute stagnation period on systems without corrosion control. However, those results have not yet been reproduced in the United States. The Water Research Foundation reported inconsistent results with water testing to identify leaded portions of service lines.
Until more is known, the Collaborative does not recommend water testing for the sole purpose of conclusively identifying whether or not an LSL is present. The risk of false-negatives and false positives is too high.
Where communities use water testing as a service to engage consumers and help them understand the issue better, they should be careful to convey that a single test does not reflect the actual risks posed by LSLs. They should communicate that as long as an LSL is present, periodic testing is advisable and the LSL should eventually be replaced.
The City of Montreal showed success with a method that involved a 30-minute stagnation period on systems without corrosion control. However, those results have not yet been reproduced in the United States. The Water Research Foundation reported inconsistent results with water testing to identify leaded portions of service lines.
Until more is known, the Collaborative does not recommend water testing for the sole purpose of conclusively identifying whether or not an LSL is present. The risk of false-negatives and false positives is too high.
Where communities use water testing as a service to engage consumers and help them understand the issue better, they should be careful to convey that a single test does not reflect the actual risks posed by LSLs. They should communicate that as long as an LSL is present, periodic testing is advisable and the LSL should eventually be replaced.