Denver Water is looking to tackle lead in consumer drinking water head-on — by removing all the lead pipes in its system.

The utility organization recently announced a new three-part plan to remove the pipes in its service area over the next 15 years. Jim Lochhead, the CEO and manager at Denver Water, said that in order to get ahead of health concerns with lead in the water, “the ultimate solution is just removing these lines altogether.”

The organization presented the plan to the Environmental Protection Agency in September, and expects a decision by the end of 2019. Public comment on the plan is open until Oct. 10. Lochhead estimates the plan will cost between $300 million and $500 million depending on how many lead pipes there are.

In addition to replacing an estimated 50,000 to 90,000 lead service lines, Denver Water will distribute water filters to customers who may have lead lines, so they can get lead out of their drinking water before their lines are replaced. The utility will also increase the pH levels from 7.8 to 8.8, in order to prevent lead from leaking into the water.

The Colorado Department of Public Health and Environment asked Denver Water in March 2018 to begin the process of adding orthophosphate to its system by 2020. Similar to increased pH levels, orthophosphate creates a coating on the inside of pipes and reduces the likelihood of lead getting into water.

Ron Falco, the safe water drinking program manager for the department, said the state looked into putting the additive into the system after lead levels in Denver Water homes with lead service lines or plumbing were too high in 2012. Falco added that several utilities in the state are already using orthophosphate.

“It showed that (Denver Water’s) current corrosion control that they use is not optimized,” he said.

There are not dangerous levels of lead in the water currently. Denver Water collects tens of thousands of water samples annually, Locchead said. EPA rules require that action is taken if more than 10% of homes tested with known lead service lines or plumbing have lead levels above 15 parts per billion. The only time this happened in Denver Water was in 2012.

Since most of the lead lines are customer-owned, Denver Water does not know which homes have lead and which do not — and many customers don’t either. Homes built before 1951 are the most likely to have lead pipes, as Denver Water began to allow galvanized and copper pipes in construction in 1949. Copper pipes continued to have lead solders to connect the pipes. Denver Water banned the use of lead pipes in 1971, according to its website. Lochhead said the utility would use this information, as well as testing and permitting data they have collected to help determine which houses need line replacements.

“It’s a number of different ways to kind of sleuth out where we think they’re going to be,” he said. “Over the course of 15 years, we’re hopeful that our methods for identifying these lines will continue to improve.”

Denver Water’s policy is to remove lead pipes when it comes across them. Around 1,200 lines are replaced every year. The organization also offers free water testing to homes. Denver Water serves around 1.4 million people in metro Denver.

Denver Water also had concerns about using orthophosphate. On one hand, Lochhead called adding chemicals to drinking water a “delicate balance.” Denver Water wants to ensure its product is clean and safe to drink, but also tastes good for customers.

“We would prefer to avoid adding new chemicals to our drinking water,” he said. “We like to produce a really good product.”

Its research indicated that while orthophosphate would reduce lead levels by 74%, it would take 50 years to remove the pipes at the pace the organization currently works at. The lead pipe removal program, on the other hand, would have all lead pipes out of the system in approximately 15 years.

The organization also had concerns about investing in adding the additive to its water, when other organizations such as the Metro Wastewater Reclamation District would have to later remove orthophosphate from its system in order to prevent it from going directly into waterways. Neighboring water utilities in Highlands Ranch and Parker in the south, and Adams County and Thornton in the north, connect to Denver Water’s service network. Those entities would also have to remove orthophosphate from their systems.

A spokesperson from Metro Wastewater said the company was not taking questions at this time because the plan is still pending EPA approval.

“This issue presents an opportunity to collaboratively implement a comprehensive regional plan that prioritizes the full spectrum of public health factors,” reads a statement on the Metro Wastewater website. “By making smart infrastructure investments, like those Denver Water has recommended to CDPHE, we can maintain the top-quality drinking water we enjoy today while targeting and removing the source of lead contamination to permanently fix this critically important public health issue.”

Lochhead estimated that implementing orthophosphate into the Denver Water system would cost between $500 million and $700 million, as well as annual costs to purchase the additive.

Denver Water also had concerns about the environmental impact orthophosphate would have. Many of the organization’s customers use water for their lawns, which ends up in local streams and rivers. Under the right conditions, this could cause accelerated algae growth. Falco said that it often takes time for those impacts to become apparent. Smaller utilities have not seen issues yet, but Falco added that Denver Water is one of the largest water providers in the state.

Denver Water worked with the Colorado Department of Public Health and Environment, as well as Metro Wastewater and environmental groups, to come up with an alternative solution, and developed the lead pipe removal plan. If approved, it will be the largest removal program in the United States.

If the EPA does not approve the plan, Denver Water will begin implementing orthophosphate into its system in March 2020. Falco said that Denver Water has already been working with Public Health to prepare for implementation next year.

Lochhead said he thinks that the removal plan is safest. Instead of mitigating the issue through additives, the pipes are replaced altogether.

“The water that we have in our system in safe. It’s a plumbing issue in the system that needs to be corrected,” he said. “We think what we are proposing is more protective of public health.”