To accelerate Denver Water鈥檚 lead reduction program and prioritize communities most at risk to lead exposure, we developed a predictive model using machine learning and known pipe and water quality samples that accurately predicts the location of lead service lines across entire networks.
It is estimated there are 9.2 million lead service lines (LSL) serving water to properties in communities across the U.S. Owned by the customer, these LSLs contaminate clean drinking water with lead creating a risk to human health.
In 2019, we helped Denver Water negotiate a variance from the United States Environmental Protection Agency (EPA) and Colorado Department of Public Health and Environment to allow a holistic approach to lead reduction rather than optimal corrosion control treatment (CCT) with orthophosphate. Proactive LSL replacement was determined to be a more cost-effective approach to protect public health and the environment, and to advance the benefits of lead reduction by decades. LSL replacement provided the added benefit of avoiding phosphate loading in the wastewater system and the need for expensive treatment upgrades. We are now overseeing the implementation of the accelerated lead service line replacement program.
Our approach
With an estimated 64,000 to 84,000 LSLs and an Administrative Order mandating their replacement within 15 years, we prioritized activity based on health equity and environmental justice needs. To accelerate the program, we developed a lead service line predictive model using machine learning and known pipe and water quality samples to make predictions across entire networks and prioritize filter distribution to reduce lead exposure prior to LSL replacement. Task orders for the accelerated LSL replacement works were defined to address communities at greatest risk of lead exposure and its consequences, including young families in underserved communities.
Outcome
The program has accelerated dramatically: after replacing about 5,000 LSLs annually from 2020 to 2022, IIJA funding doubled that pace in 2023, bringing total replacements to more than 35,000. This progress puts Denver Water on track to eradicate LSLs in their network well in advance of their initial 15-year deadline and protect communities from exposure to lead in drinking water.