In late 2023, EPA released the proposed Lead and Copper Rule Improvements (LCRI). See this article for more information on the proposed LCRI.The LCRI is intended to improve upon the requirements promulgated in early 2021 in the Lead and Copper Rule Revisions (LCRR). The LCRR/LCRI will affect more than 1,050 community and non-transient, non-community public water systems in Colorado, serving nearly 6.5 million people. The LCRI public comment period is closed and EPA is planning to finalize the rule in October 2024. The LCRI compliance date is estimated to be late 2027. This gives water systems time to prepare and optimize their corrosion control treatment (CCT) before the LCRI requirements take effect.
What is corrosion control treatment (CCT)? CCT is chemical treatment at the water treatment plant that makes the potable water less corrosive to water lines and premise plumbing. CCT is typically achieved by adding a phosphate-based corrosion inhibitor or with pH/alkalinity adjustment. The Lead and Copper Rule (Section 11.26 of Regulation 11) requires installation of CCT for systems with action level exceedances (ALE) and requires optimal corrosion control treatment (OCCT) for all systems serving more than 50,000 people. Approximately 65 systems in Colorado are operating OCCT with Department set optimal water quality parameters (OWQP) to comply with the current Lead and Copper Rule.
Several changes in the proposed LCRI may impact systems that either have corrosion control treatment (CCT) installed currently or that may need to install CCT as a result of elevated lead or copper levels. Proposed LCRI changes that may impact CCT include:
- Setting a lower lead action level at 10 parts per billion (ppb).
- 1st and 5th liter lead sampling at lead service lines may result in higher lead levels than seen under the current rule.
- Corrosion control study required for large systems without OCCT that exceed the practical quantitation limit (PQL) of 5 ppb based on 90th percentile lead levels.
- Medium and large systems with lead service lines that are required to conduct a corrosion control study must use harvested lead pipe in a pipe loop rig.
- Deferred OCCT installation or re-optimization for systems that replace 100 percent of lead service lines within five years of the date they trigger CCT steps.
- Removal of hardness as a corrosion control treatment option and specifies any phosphate inhibitor must be orthophosphate.
- Small system compliance options (e.g., point of use devices, replacement of all lead-bearing plumbing materials) for community water systems with 3,300 people or less and all non-transient, non-community systems.
- Review of CCT during sanitary surveys.
While these changes were part of the proposed LCRI, we will need to wait for the final rule to see if all of these items are included and if new items are added. Also, under the proposed LCRI, water systems will also have to provide Tier 1 public notice to consumers within 24 hours after a lead action level exceedance.
Possible actions to take:
- Review your 90th percentile lead results: One of the key changes in the draft LCRI is setting the lead action level at 10 ppb; the current lead action level is 15 ppb. Since 2010, approximately 115 systems had 90th percentile lead levels that were between 10 ppb and 15 ppb. Investing in operational controls, treatment, and/or treatment optimization now may allow you to lower your lead levels below the 10 ppb action level before the LCRI takes effect.
- Evaluate treatment at large systems that are deemed optimal: Systems that have a population of more than 50,000 people “large systems” are required to have optimal corrosion control treatment (OCCT). The majority of Colorado’s systems that serve over 50,000 people have been “deemed” to have OCCT based on low source water lead and 90th percentile lead concentrations less than 5 ppb. The proposed LCRI requires large systems with a 90th percentile lead value greater than 5 ppb to complete a corrosion control study (CCS). For systems with lead service lines, the proposed LCRI requires the CCS be completed using harvested lead lines in a pipe loop. Many large systems have treatment processes that may impact corrosion. If possible, you should work on optimizing any existing treatment to lower lead levels as much as possible.
- For systems with CCT, determine if you can optimize your treatment process: Analyze your treatment process and determine if your corrosion control treatment could be optimized. A great tool for this is a bench scale immersion coupon study.
- pH/alkalinity CCT systems: Systems using pH/alkalinity adjustment may want to more tightly control pH and/or find the optimal target pH. The EPA guidance document recommends a pH range at the entry point of 0.4 s.u. (for example: 7.8 to 8.2 s.u.) and a 0.6 s.u. range within the distribution system. Maintaining a tighter pH range may also improve other water quality contaminants such as disinfection byproducts. Conducting an immersion study to determine the optimal pH target may also be beneficial.
- Phosphate-based inhibitor systems: Phosphate-based inhibitor systems may want to optimize their dosing. Orthophosphate is the chemical that is effective at corrosion control and the EPA generally recommends a minimum orthophosphate concentration of 1.0 mg/L as PO4 in the distribution system. Blended phosphate inhibitors are a blend of orthophosphate and polyphosphates, which are typically used to sequester iron and manganese. These systems may want to review the percentage of orthophosphate in their chemical to better control corrosion. A bench scale immersion coupon study may be advantageous to determine the more effective dose and/or chemical.
- Systems with CCT and OWQPs should review their OWQPs: Systems with OWQPs should review their monitoring schedule to verify the required OWQPs at the entry point(s) and in the distribution system. You may want to request an OWQP modification if you have additional water quality data or immersion coupon study results.
Making changes to your CCT now can help you meet the LCRI requirements that are coming down the pipe. If you have any questions, please contact Melanie Criswell at melanie.criswell@state.co.us.
Resources:
- LCRR guidance, FAQs, and forms are available on the department’s Lead and Copper Rule & Revisions Webpage.
- Review the department’s initial service line inventory development policy.
- Visit the department's drinking water training and assistance website to register for upcoming Lead and Copper Rule courses (online and in-person options available) and other free training opportunities.
➽ Melanie Criswell Lead Service Line, Corrosion, and Emerging Contaminants Engineer
➽ Haley Orahood Regulatory Development and Implementation Specialist
