FOLSOM, California — The City of Folsom has experienced a significant decrease in pinhole leaks in copper water pipes in local residences since adding orthophosphate to the water system.
This past summer, the California city of 80,000 experienced what residents dubbed "a pinhole leak apocalypse."
Water leaks in homes have developed nearly 1,400 times since the onset of the problem.
On the recommendation of consultants, the city started adding orthophosphate to the water treatment system in October.
Folsom's environmental and water resources director, Marcus Yasutake, says it's had the desired effect.
"If you just look at weekly trends in terms of the number of calls, it's been reduced significantly in the last, I would say, four weeks," Yasutake said in an interview with TBNewswatch.
He said the city received 131 complaints about pinhole leaks five weeks ago, but the weekly total fell steadily to just a dozen reports in the most recent week, adding "so the trend is going in the right direction."
Orthophosphate applies a protective coating layer to the inside of water pipes.
Along with sodium hydroxide, it is also one of several methods approved by the Ontario government for mitigating lead corrosion, as outlined in a statement from the environment ministry earlier this year:
- pH adjustments or alkalinity increases to make water less corrosive when it contacts lead bearing-pipes and faucet fixtures. The use of sodium hydroxide is one method of adjusting pH, and the ministry also accepts the use of calcium hydroxide
- apply a protective coating to surfaces of lead pipes through the use of orthophosphate
- removal of lead service lines, and lead filters on faucets
- education and outreach regarding lead exposure and measures residents can take to limit exposure to lead in drinking water
Although sodium hydroxide is approved for corrosion control, the City of Thunder Bay stopped adding it to its water supply earlier this year after receiving increasing reports of pinhole leaks.
According to the environment ministry, it's used by many cities in North America including Ottawa, London, Ont., Edmonton, New York City and Boston as part of their measures to minimize corrosion and control lead "without any pinhole issues."
The chemical characteristics of Folsom's water system may be quite different from Thunder Bay's, so it's not certain that orthophosphate would be a suitable alternative treatment for Thunder Bay's water system.
Folsom's consultants said that city's problem likely arose from a combination of factors.
The consultants found that the water's purity, combined with a pH above 9.0 – pH being a figure expressing the acidity or alkalinity of a solution on a scale on which 7 is neutral – and the use of chlorine could contribute to pitting of copper pipe, eventually leading to pinholes.
Thunder Bay's 2019 drinking water quality report shows the pH level last year ranged between 8.3 and 9.6, and that the objective was 7.0 to 9.5.
It's unknown whether treatment with orthophosphate is one of the options that Thunder Bay is now looking at.
In a statement in October, it said "The City is committed to ensuring that Thunder Bay's drinking water is safe for consumption through its review of the Corrosion Control Plan. The City has nothing further to offer in terms of further comment on the situation."
The city is now facing two major lawsuits related to pinhole leaks, including a $350 million class action on behalf of affected homeowners, and a separate $350 thousand lawsuit from St. Joseph's Care Group for the cost of damages and repairs in the PR Cook apartment complex at St. Joseph's Heritage.