A recent spike in phosphate levels in pools around Los Angeles has service technicians looking for answers. Some are blaming the local utility. But the problem doesn’t seem to affect the entire area. Specifically, techs have noticed the change in the San Fernando Valley and West L.A., including Beverly Hills and Bel Air.

Eric Nielson, owner of Willow Creek Pools in West Hills, Calif., said phosphate wasn’t a problem until the last couple of years.

“We didn’t have to [test] for it in the past,” he said. “All of a sudden, we go from nothing to between 3,000 and 5,000 parts per billion.”

Other professionals have seen readings as high as 6,000 ppb.

“The phosphate levels have been off the charts,” said Saul Krochmal, owner of Premium Pool Service in Los Angeles.

For some of these techs, the problem has necessitated the use of phosphate removers more often than normal.

Nielson believes the problem stems from a chemical compound that the Los Angeles Department of Water and Power has been adding to its system. Zinc orthophosphate is a corrosion inhibitor used to protect piping in water-delivery systems.

The substance coats the piping and is meant to prevent particles of lead and copper from leaching into the water.

But the cause for the high phosphate levels is not cut and dry.

For one thing, several technicians serving the areas in question haven’t had such problems.

Jeff Von Dwingelo, owner of Waterdog Pool Service in Los Angeles, counts among those professionals.

“I have 55 pools and none of them have any algae,” he said.

And while the LADWP confirmed that it has been adding zinc orthophosphate to its water system in West Los Angeles, it does not add anything in the San Fernando Valley.

“We do have one corrosion control station on the west side,” said Melinda Rho, a water quality manager for the utility. “We’ve been providing it there since 2010.”

And at least one expert doesn’t see a direct link between the increased dosing of zinc orthophosphate and the pool problems. Bruce Macler, a water program toxicologist for the Environmental Protection Agency, stated that phosphate readings of approximately 3,000 parts per billion are normal.

“Those levels are not problems for public health, nor are [they] likely to be of much concern for algal growth,” he said.

He added that LADWP would be adding the compound at the treatment plant, so if phosphate was high in one spot, it would be high all over the city.

According to Macler, the normal rate of phosphate in drinking water should fall between 1 and 10 parts per million. Rho stated that the average rate of phosphorus in Los Angeles ranges between .75 ppm and 2 ppm, well within Macler’s numbers.

Chemical expert Harold Evans doesn’t believe zinc orthophosphate alone has caused the phosphate spikes. Instead, he believes that because of the drought, any chemicals added to the water system become more concentrated.

“As water sources diminish, you get concentration — the TDS level is going to elevate,” said the president of Orenda Technologies.

Another factor may be the wildfires that have taken place in California, he added. The combination of ash from the blazes and phosphorus in fire retardants could be making its way into the water.

As Evans sees it, the pairing of a diminished water supply with the influx of phosphorus from several different sources could explain the phosphate spikes.

While the cause of high phosphate levels may remain in question, the LADWP indicated why there may be a rise in algal blooms. It began adding chloramines to its supplies in May 2014.

According to Jonathan Leung, assistant director of the utility’s Water Quality Division, the utility began using chloramines to replace the chlorine that they had used before.

“Nearly all Southern California utilities have switched to chloramines,” he said.

Chloramines are a combination of chlorine and ammonia. According to Rho, the ammonia disassociates from the chlorine. Because it’s full of nitrates, the disassociated ammonia provides a perfect breeding ground for algae.

“It’s why we encourage homeowners to cover their pools,” Rho said. “We’ve had to cover all of our reservoirs to prevent algal blooms.”