Denver Water, which serves water throughout the region surrounding Denver, Colorado, USA, is set to receive $76 million in funding from the U.S. Bipartisan Infrastructure Law to accelerate the pace of its lead-service line (LSL) replacement plan.
That plan was recently given full approval1 and found to be effective by the nation’s Environmental Protection Agency (EPA) (Washington, DC, USA).
In doing so, the EPA openly backed the utility’s novel approach for reducing lead in drinking water by issuing a final variance under the U.S. Safe Drinking Water Act. The variance allows Denver Water to continue implementing its protocols.
“Denver Water’s approach to tackling lead in drinking water has been remarkable and an example for other communities across the country,” says KC Becker, regional administrator for the EPA. “Thanks to new funding from the Bipartisan Infrastructure Law, the utility’s customers can expect an even faster lead service line replacement schedule to deliver health protections.”
As a result of EPA’s first-of-its-kind lead variance approval, Denver Water says it will continue to:
- Replace all LSLs at no direct cost to customers;
- Control lead corrosion with pH and alkalinity treatment;
- Determine the locations of LSLs that connect homes and buildings to water mains;
- Provide a water pitcher filter certified to remove lead to customers with LSLs;
- Conduct extensive community outreach and education.
Three-Year Trial Program
On a three-year trial basis in 2019, EPA issued the first lead variance in the country to this project to evaluate whether Denver Water’s alternative approach could be effective.
After evaluating the data, EPA approved another variance to allow the utility to continue with its current plan. The agency says this plan has proven to be more effective than orthophosphate treatment, the method of water treatment that was previously required under federal and state regulations.
By adjusting the water’s chemistry, city officials believe it is possible to cause a buildup or coating on pipe walls, which can reduce the amount of lead released from lead-containing pipes and fixtures. Since the program officially started in January 2020, Denver Water has replaced more than 15,000 LSLs.
“Denver Water proposed this holistic approach because we believe it is most protective of future generations and is in the best interest of public health and the environment,” says Jim Lochhead, CEO and manager at Denver Water. “By tackling the issue at its source, our plan will eliminate lead-service lines—the most significant source of lead in tap water—within 15 years and have fewer impacts to rivers, streams, and reservoirs.”
How Lead Enters Water
While the source water delivered to homes and businesses is lead-free, lead can get into the water as it moves through customer-owned service lines and lead-containing plumbing, the utility explains. The service line is described as the small pipe that connects to Denver Water’s pipe in the street and carries water to homes. The area’s homes and buildings most likely to have LSLs are those built before 1951.
“Removing these lines is the most effective way to eliminate this source of lead exposure, and we are committed to this program until every lead-service line has been removed,” Lochhead says.
As part of its 2019 proposal,2 the utility asked EPA to grant a variance from the usual treatment requirements under the U.S. Safe Drinking Water Act’s Lead and Copper Rule (LCR). For nearly 30 years, as part of the LCR, the utility monitored the water quality of homes with LSLs to determine if the water’s corrosivity needed to be adjusted to minimize the risk of lead getting into the water supply.
Only once, in 2012, did sample results indicate that action needed to be taken to optimize corrosion control, and Denver Water says it remained in compliance. However, the utility is still required to implement the best method to reduce risks, and it found that orthophosphate treatments can have unintended consequences.
Unintended Consequences
“Despite its benefits, orthophosphate added to drinking water can increase phosphorous levels in wastewater and storm water, resulting in adverse impacts to wastewater treatment plants and downstream reservoirs, streams, and rivers,” the utility says. “Once started, orthophosphate treatment cannot easily be discontinued without causing an increase in corrosion, making orthophosphate a potentially permanent treatment method.”
As a result, Denver Water convened working groups in 2018 with the state’s public health and environmental agency, as well as other stakeholders, to evaluate the benefits and risks of orthophosphate alongside other options.
During that process, Denver Water investigated whether a lower dose of orthophosphate, increasing pH as part of an accelerated replacement of LSLs, and providing filters to affected customers could achieve the same or greater reduction in exposure risk. After analyzing, they chose the multi-faceted approach.
“Overall, as compared to orthophosphate, the program provides a holistic and permanent lead reduction approach that is as effective at protecting public health, more efficient in reducing lead exposure, less harmful to the environment, more equitable in its public health benefits, and potentially more cost-effective with fewer regional risks,” Denver Water says.
Specifically, the utility became concerned by the ripple effects of adding orthophosphate into the larger water supply. Under the right conditions, they believe this could set off a chain of problematic events, such as accelerating the growth of algae in area lakes, reservoirs, and ponds.
The New Approach
By contrast, this program aims to replace all customer LSLs to remove the most significant source of potential lead, as well as further increasing the pH level of drinking water to help prevent corrosion from homes with lead fixtures and pipes with lead solder.
As part of this program, Denver Water is providing at-home water filters to all customers suspected of having an LSL, free of charge, until the line is removed. They estimate that filters will be distributed to over 100,000 homes.
The original goal of this program, fully funded by the utility, was to replace ~75,000 LSLs within 15 years, all at an average of 7% per year. By comparison, the utility’s prior pace would have needed more than 50 years to achieve the same number of replacements.
However, the new Bipartisan Infrastructure Law funding will further speed up that timetable. According to Denver Water, the money will be spent in 2023 through 2025 and is expected to replace up to 7,600 LSLs, all while shortening the 15-year program by approximately 18 months. According to the utility, between 3,000 and 5,000 additional lines will be replaced in 2023—on top of the nearly 5,000 lines that were already planned for replacement this year.
“For every 4,500 additional lead-service lines replaced using the federal funding, the overall length of the program will be one year shorter,” Denver Water says.3
At this time, the utility is prioritizing replacements in underserved communities and homes with higher populations of children and pregnant women. According to EPA, no safe level of lead exposure has been identified for children, which makes them particularly vulnerable. Lead exposure can pose a significant health and safety threat to children and can cause irreversible and lifelong health effects.
“Local, state, and federal partners collaborated to develop and implement this innovative approach, which has proven to be a success for public health, environmental protection, and environmental justice over the last three years,” says Ron Falco, safe drinking water program manager for the Colorado Department of Public Health and Environment (Denver, Colorado, USA).
Upcoming Steps
The replacement work is being done by contractors and by Denver Water crews, who replace any LSLs found during scheduled pipe replacements or during repair work on a broken water main. In addition to installing a lead-free, copper line at no direct cost, customers also receive water pitchers and filters certified to remove lead.
The new plan is expected to have a positive economic impact, as well. The regional cost impacts related to orthophosphate were estimated to be between $480 million and $714 million, whereas the variance plan should cost between $304 million and $556 million, according to the utility’s estimates.
Established in 1918, Denver Water is a public agency funded by water rates and new tap fees, rather than taxes. It is Colorado’s oldest and largest water utility, and it serves approximately 1.5 million people in the Denver area.
Sources: Denver Water, www.denverwater.org; U.S. EPA, www.epa.gov.