Corrosion Control Studies
If your system has exceeded the lead action level of 15 μg/L, you will to follow the following schedule after consulting your state-specific regulations.
Within 6 months after the end of the monitoring period with the Lead Action Level (LAL) exceedance, recommend optimal corrosion control treatment (per 141.82)
Within 12 months after the end of the monitoring period with the LAL exceedance, the State may require the utility to perform corrosion control studies (per 141.82(b)). Corrosion control studies shall be completed within 18 months from when the State requires the studies. Studies may include pipe loops, coupons tests (only to reduce the number of alternatives tested in pipe loops), partial-system tests or analyses based on documented analogous treatments with other systems of similar size, water chemistry and distribution system configuration.
After corrosion control studies are complete, the State will designate optimal corrosion control treatment within 6 months.
Once State the optimal corrosion control treatment has been designated, you need to:
- Install optimal corrosion control treatment within 24 months
- Complete follow-up sampling within 36 months
State reviews system’s installation of treatment and designates optimal water quality parameters after follow-up sampling is complete.
System shall operate in compliance with the State-designated optimal water quality control parameters and continue to conduct tap sampling.
Acceptable treatment alternatives
- Alkalinity and pH adjustment
- Addition of orthophosphate as corrosion inhibitor (1 mg/L residual and 3 mg/L residual)
- Addition of a silicate-based corrosion inhibitor
- Other treatments approved on a case-by-case basis
- No calcium carbonate stabilization as it does not form a film on the lead pipes
Cannot exclude a treatment alternative based on impact on other water quality treatment processes, simultaneous compliance or other impacts. It is to be noted and considered as part of the CCT study.