What’s wrong with northeast Fresno water? Virginia Tech tests underway seek answers

A university professor in Virginia is conducting tests on pipe and water samples from Fresno in search of solutions to discoloration and lead contamination issues in tap water in northeast Fresno.

Two employees from the city’s water division are heading to Blacksburg, Va., to meet Monday with Virginia Tech professor Marc Edwards, one of the nation’s leading experts into corrosion in municipal water systems. Edwards, a professor of civil and environmental engineering, is consulting on the city’s investigation into residents’ complaints about red- and brown-tinged water coming from their faucets in the area served by Fresno’s Northeast Surface Water Treatment Plant.

The plant is shut down for three months while the irrigation canal that feeds it goes through annual maintenance.

Edwards’ pipe tests come as the number of residents asking for water testing because of the discolored-water issues continues to mount. There are about 22,500 homes in the northeast Fresno area served by the treatment plant.

Since January, when the water problems in homes plumbed with galvanized pipes gained widespread attention, about 1,800 homeowners in northeast Fresno have asked the city to test their water.

To date, of more than 1,400 homes for which the city has received test results, 315 have at some point shown levels of lead in the water above 15 parts per billion – the maximum allowable under U.S. Environmental Protection Agency standards – from at least one indoor faucet.

As repeat tests have been done and the city has adjusted its treatment at the plant, the number of homes exceeding the lead standard has dropped to 276, in which 29 are reporting lead from kitchen faucets and 126 from bathroom sink faucets, according to figures released Friday by the city.

Also, of residents who have requested water testing and responded to a survey sent last month, 42 percent reported either reduced or no discoloration in their water, said city spokesman Mark Standriff.

The EPA and health experts say kitchen and bathroom sink faucets are of the greatest concern for lead because those are fixtures most frequently used for drinking water, compared to bathtubs, showers and laundry/utility rooms. About 75 percent of all fixtures tested by the city have shown no detectable signs of lead.

Detailed pipe tests

Edwards and his research team, who also are investigating lead contamination issues in Flint, Mich., were awarded a $150,000 contract last month by the city to test samples of galvanized pipes collected from Fresno homes and water from the Enterprise Canal, which supplies water from Pine Flat and Millerton lakes to the city’s treatment plant on Chestnut Avenue north of Behymer Avenue. The treated water is then piped through the city’s water mains to residents and businesses in northeast Fresno.

Various pipe samples are being submerged for extended periods of time in samples of water with varying levels of pH, alkalinity and corrosion-control chemicals. The combinations of water chemistry that cause the lowest degrees of corrosion and release of zinc from the galvanized coating inside the pipes will then be applied to “pipe loop” testing, in which treated water is pumped through pipe segments on a continuous basis and monitored for corrosion.

Vernon Snoeyink, a professor emeritus at the University of Illinois at Urbana-Champaign, and Los Angeles-based Water Quality & Treatment Solutions Inc. will do the pipe loop tests under a separate $200,000 contract from the city.

For decades, Fresno relied solely upon pumped groundwater to meet the drinking water demands of residents and businesses across the city. But as constant pumping strained the area’s water table and wells in northeast Fresno struggled to keep up with demand, the city developed plans for a treatment plant to use surface water, too. The northeast plant, which can treat up to 30 million gallons of water daily, opened in 2004.

Some residents have said they’ve been dealing with discolored water problems since shortly after the treatment plant became operational 12 years ago.

While the scientists said the water coming from the treatment plant met water-quality standards on its own, Edwards and Snoeyink believe the differences in water characteristics between the surface water and groundwater – and the fluctuation between the two sources depending on daily swings in customer demand – destabilized deposits of rust and minerals that had accumulated for years on the inside of galvanized pipes in some northeast Fresno homes. That, in turn, resulted in discolored water flowing from taps in affected homes.

Snoeyink told residents this year that lead found in the water at some homes was more likely leaching from household fixtures made with lead in the brass from which they were manufactured, rather than from corroded galvanized pipes.

He encouraged residents to replace older brass faucets in kitchens where households draw most of their drinking water. Faucets manufactured before 2010, Snoeyink added, contain about 8 percent lead and tend to release higher levels of lead into water.

New treatment plan

Edwards’ tests and Snoeyink’s pipe loop tests will provide the basis of a water treatment strategy for not only the northeast treatment plant, but also for a new, larger treatment plant now under construction in southeast Fresno.

It will supplant a 1998 corrosion-control study that the city commissioned as it planned the northeast treatment plant. That study, which Edwards described as “state of the art” for its time, likely gave Fresno’s plant operators a sense of false confidence in their treatment strategy from 2004 through 2015.

“I wouldn’t say the report was inherently flawed,” Edwards said of the 1998 research. “I think it reflects the naiveté of the time that we thought we understood something we really didn’t.

“We can do all the lab studies in the world and make a hundred predictions, but the bottom line is, is this performing satisfactorily in people’s homes?” Edwards said. “If the answer is no, our science was wrong. And that’s what happened here (with treatment at the northeast plant). The predictions just were not right.”

Since this spring, the city has tinkered with incremental adjustments to treatment at the northeast plant to bring the pH and alkalinity of the treated surface water more in line with the groundwater.

The plant was shut down in late September, an annual hiatus while the Fresno Irrigation District conducts maintenance and repairs to its Enterprise Canal, Standriff said. The plant will remain closed until January, when the city will resume treatment operations using the revised strategy.

This story was originally published October 28, 2016 at 3:15 PM with the headline "What’s wrong with northeast Fresno water? Virginia Tech tests underway seek answers."