Orthophosphate and Lead Contamination in Drinking Water

Analies Dyjak  |  Policy Nerd

Lead contamination in drinking water is a huge problem for municipalities with an older infrastructure. Lead contamination occurs when water comes in contact with lead pipes. This article discusses a common additive used to combat lead pipe corrosion.

What is Orthophosphate?

Orthophosphate is a common corrosion inhibitor used by water suppliers to prevent lead pipes from leaching. When orthophosphate water treatment is added to a water source, it reacts with lead to create a mineral-like crust inside of the lead pipe. This crust acts as a coating which prevents further lead corrosion. The use of orthophosphate treatment in drinking water became popularized in 2001, during the lead crisis in Washington, D.C. Lead contamination in many cities including D.C. and Flint, occurs when a city’s water becomes more corrosive, which can allow for lead from pipes to leach into the drinking water supply. When the lead problem initially occurred, cities such as Flint, Michigan, Durham and Greenville, North Carolina, and Jackson, Mississippi didn’t learn from D.C’s mistakes and all had lead outbreaks. 

Does Orthophosphate Fix Lead Contamination?

It certainly can. Once the protective layer is formed, cities can find that lead concentrations in the water drop by 90%. However, Orthophosphate is somewhat of a bandaid to temporarily fix the presence of lead in drinking water. For example, if the protective layer is corroded away or otherwise disturbed (e.g. in the case of a partial service line replacement or the water’s corrosivity changes), lead can leach back into the water. Finally, not all municipalities are adding orthophosphate to drinking water because of its cost. If you have any questions regarding lead prevention in drinking water, send us an email at hello@hydroviv.com.