DENVER – Denver Water is proposing replacing up to 90,000 lead water service lines for older buildings with copper lines over the next 15 years in what could cost hundreds of millions of dollars.

Denver Water said Monday that it has a new proposal to reduce potential lead exposure caused by household plumbing and service lines that contain lead – despite Denver Water’s pipes being lead-free.

In 2012, some water quality monitoring showed levels were above Environmental Protection Agency (EPA) requirements. Denver Water was required to take action, which included coming up with a plan to reduce the risk of lead-tainted water for homes by March 2020.

The Colorado Department of Public Health and Environment required Denver Water to start adding orthophosphate to the water in 2018 to reduce levels of lead and copper. Denver Water said it will continue that effort but is proposing the new alternative method of replacing the service lines and increasing the water’s pH level.

In addition to boosting the pH level, which will make the water less corrosive, Denver Water wants to replace what it says are between 50,000 and 90,000 lead service lines with copper lines over the next 15 years. Most of the service lines are for homes built before 1951.

Denver Water says those replacements would be done free-of-charge to the customers, though rate-hikes would likely increase.

It also wants to give all customers in the Denver area that have suspected lead service lines at-home water filters for free.

The plan will still have to go through the EPA approval process, but Denver Water plans small-scale testing before finalizing its proposal.

A release from Denver Water said the cost of the changes to the plan “will be better understood after further analysis this summer” but The Denver Post reports replacing the service lines would cost around $5,000 per home – up to nearly $500 million if 100,000 homes need to have their lines replaced.

Denver Water plans to host community events this summer to further discuss the proposal with community members. Denver Water says it is continuing to identify and confirm where all the service lines exist.

Part of the project would be developing new mapping tools and ways to identify where the lines were placed in the first place.

In the meantime, people can request a test for lead here. For more information on the proposal, click here.

In response to the project, the CDPHE released the following statement: