In December 2022, the EPA announced final approval renewing Denver Water’s variance from the lead and copper rule provisions associated with Optimum Corrosion Control Treatment (OCCT). What a great success story for promoting the culture of health! Search the Aqua Talk blog for “culture of health” to learn more. The variance includes a multi-pronged approach to reducing lead in drinking water. This new variance replaces the initial variance approved by the EPA on December 16, 2019.
When a public drinking water system exceeds the lead action level, the state and water system must ensure that adequate steps are taken to limit lead contamination. One step in that process is often accomplished by installing OCCT, which is the treatment that minimizes lead concentrations in the tap water. Based on Denver Water’s corrosion control study, the data showed that orthophosphate was the OCCT. Denver Water, the department, and EPA worked in partnership to develop a variance from the treatment requirement. EPA approved the variance and we are responsible for ensuring the program is run under the agreement. All parties agree that this program is better for public health, environmental protection, environmental justice, and cost effectiveness.
Over the next 12 years, CDPHE will provide help and regulatory oversight of the variance. This effort includes:
- Removing all lead service lines (LSL) within the service area by the end of the variance.
- Providing filters that are NSF rated to remove greater than 90% of lead from the drinking water, while consumers are awaiting service line replacement. The filter program is currently serving approximately one hundred thousand people who all need new filters every six months! All residences estimated to have known or suspected lead service lines are enrolled in the program.
- Adjusting the pH of all water treated to reduce corrosivity. This pH adjustment will be the corrosion control treatment even after all of the LSLs have been removed.
- It is also important to note that there is also a great focus on health equity & environmental justice (HE&EJ) in the LSL removal process. Denver Water's LSL removal rate in communities identified by the EPA’s EJScreen tool is at least equal to the removal rate in the entire service area. For more information, please review the information provided by the EPA here.
- For updated statistics regarding the variance, please see Denver Water's Online Dashboard. The dashboard also shows how many lead service lines have been replaced.
It was an incredibly collaborative process to update the final variance between local, state, and federal agencies. This process took place over several months throughout 2022. The group analyzed what worked and what could be improved upon in 2020. Then, the variance review needed to go through the applicable legal processes, and public comment periods. It is exciting that local, state and federal partners effectively collaborated to develop and then implement this variance. Again, this has proven to be a success for public health, environmental protection and environmental justice. The department worked closely with Denver Water to implement this variance in the first three years. We will continue our oversight role throughout the duration of the variance.
At this point, Denver Water has met or exceeded all of the requirements of the variance. We are very grateful for the opportunity to work with everyone involved. We expect for this trend to continue, and even accelerate, as bilateral infrastructure law (BIL) money is awarded.
➽ Ben Keilly, Drinking Water Compliance Assurance
