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Our CEO addresses CDPHE requirement to add orthophosphate

Statement from Denver Water CEO Jim Lochhead regarding Colorado Department of Public Health and Environment’s decision that requires Denver Water to add orthophosphate to its drinking water supply for corrosion control by 2020:

Delivering safe water is our first responsibility. The water Denver Water delivers to our customers’ property is absolutely lead-free, but lead can get into water as it moves through customers’ lead-containing household plumbing and service lines. We are committed to taking the right steps to reduce the risk of lead leaching into water through customers’ plumbing.

In the interest of public safety, we believe further study is needed regarding the potential impacts of orthophosphate on health, the full water system, other water providers connected to Denver Water, wastewater treatment and the reservoirs and streams in our watershed before an irreversible change in treatment of our water is implemented. Once fully studied, Denver Water will implement the best approach, regardless of cost. 

Denver Water would like to work with CDPHE, EPA and other affected stakeholders on a phased approach, where we could accelerate enhanced treatment for corrosion control by beginning to implement pH/alkalinity adjustments within the next few months, while taking time to work together to study other viable alternatives that will be potentially less impactful than orthophosphate injection as currently proposed.

When it comes to lead in drinking water, no levels are safe, which is why Denver Water is proactively working to get the lead out by offering free lead testing kits for customers, replacing lead lines when we come across them during our construction work and by also partnering with the Denver Urban Renewal Authority on a pilot program to make low- or no-interest financing available to homeowners who want to replace their lead service lines.

Background on corrosion control:

Denver Water has taken a proactive approach to lead corrosion control treatment and has adapted our response to lead in drinking water as science and regulations have evolved.

Nearly all metals corrode to some degree and the corrosion rate is dependent on outside factors, including water. So, water systems across the nation work to reduce the risk of lead leaching from customers’ plumbing into their tap water by reducing the corrosivity of the water supply. Denver Water closely monitors how corrosive the water is and works to reduce corrosion in the system.

As part of our efforts to optimize corrosion control in our system, we conducted a pipe-loop study on multiple methods, including increasing the pH level and adding orthophosphate. While results of the study concluded that orthophosphate reduced the corrosivity of the water more than raising the pH/alkalinity levels, neither option completely eliminates the potential of lead leaching into the water from customer service lines or plumbing.

Because the scope of the study was only focused on testing lead lines harvested from the system, our preferred approach is to work collaboratively over the next year with CDPHE, EPA and all impacted stakeholders to further study the overall impacts of this treatment change over the next year.

Orthophosphate will take up to two years to implement, while we can begin increasing pH/alkalinity levels within a few months, providing more immediate public health benefits to customers with lead service lines. This would provide us more time for a thorough and careful consideration of the best and least risky means of corrosion control in our unique dry Colorado environment to ensure we fully understand the available lead reduction strategies that are most protective of public health for all of Denver Water customers and other water providers in the metro area.


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