This weekend, more than 1,000 households in the Sunland Park and Santa Teresa neighborhoods were asked not to drink or bathe in water provided by their regional water utility.

Camino Real Regional Utility Authority says water is now safe for the areas in southern New Mexico that showed high pH readings due to a pump failure at a treatment plant that increased the basicity of the water. People in impacted areas will need to run their taps to clear water when they use water for the first time. 

The measure pH describes how acidic, neutral or basic water is. Measures that are too high or low can impact human health. 

The pH levels were high enough to potentially cause stomach and skin irritation, said Brent Westmoreland, the executive director for Camino Real Regional Utility Authority. The utility provides water and wastewater for 7,300 households along the southern portion of Doña Ana County.

“We’re shooting for 7.5,” he said about the pH level for drinkable water. “Some readings were up around 10.5 to 11, and that’s just too high.”

Water was not shut off in Sunland Park or Santa Teresa. Instead, Camino Real Regional Utility Authority directed Sunland Park Fire Department to flush higher-pH water out of the water system by opening fire hydrants near Valencia Park starting early Friday, said Chief Danny Medrano.

The utility, the City of Sunland Park, and the Doña Ana County Office of Emergency Management all bought pallets of water to hand out to residents. By Dec. 3, officials distributed at least 30 pallets of water, said Doña Ana County Emergency Manager Stephen Lopez. 

Gadsden Independent School District required eight schools to temporarily transition to remote learning starting Monday, citing the water quality issue. 

Guillermo Carmona, the spokesperson for the district, told Source NM in an email Monday evening that all eight schools will return to normal schedules Tuesday, Dec. 5. 

What happened to the water?

Westmoreland said the high pH stemmed from a malfunctioning pump for sulfuric acid at the utility’s arsenic treatment plant on the West Mesa in Las Cruces. The groundwater around Santa Teresa and Sunland Park has high naturally-occuring arsenic levels, which must be removed to make the water safe to drink.

Westmoreland said the chemical is used to increase the pH after the arsenic’s removed from the water pumped from wells at the facility.

“It was supposed to turn off automatically,” Westmoreland said. “Well this time it didn’t, and that’s what caused the problem.”

Acids, including sulfuric acid, are commonly used in water treatment to lower the pH, according to the U.S. Environmental Protection Agency. 

Westmoreland said the utility noticed the high pH on Wednesday, and had received complaints about bitter or slimy water. He said utility staff did not find the source until Thursday afternoon. He said Camino Real Regional Utility Authority repaired the pump, and there’s no expectation of further needs for funding. 

“Now we’re working on cleaning up the system,” he said, as all affected neighborhoods were able to use their tap water Monday afternoon. 

The New Mexico Environment Department was notified by the utility about the incident on Friday, according to Drinking Water Bureau Chief Joe Martinez.

He said staff with the state environment department have been on-scene since Saturday, offering technical support.

“We’re still in the preliminary stages of investigating what’s going on,” Martinez said, but anticipated there would be a report published by the state environment department at a later date.

Martinez said he expects Camino Real Regional Utility Authority to investigate and “make sure their infrastructure hasn’t been impacted,” by the change in water chemistry. 

“Once we’re confident in knowing what exactly happened, we will be working with the system to make sure that they put some safeguards in place to make sure it doesn’t happen again,” Martinez said.

What are the health concerns?

There is little harm to health from ingesting small amounts of high-pH water, said Srikanth Paladugu, the bureau chief of Environmental Health Epidemiology at the New Mexico Department of Health.

The ideal pH variation for the human body is 6.5 to 9 on a 14-point scale, Paladugu said. 

“Drinking small quantities of (basic) water does not cause any harm, because the human body is very resilient in managing the pH for itself,” he said.

Paladugu said Camino Real Regional Utility Authority water reaching 10 on the pH scale during this incident means it’s outside of that ideal range and can have some side effects. Drinking alkaline or basic water at that level can cause irritation of the stomach, tongue and throat, and if used for bathing, also irritate the skin. 

“If you keep drinking that water, it’s not safe,” Paladugu said. “That’s why the do not drink order was issued.” 

Camino Real Regional Utility Authority water has high levels of arsenic, both from the geology of the groundwater, but also from industry sources, according to its end of year water quality report. 

Paladugu said that more basic water can increase arsenic levels, and recommended customers using home filtration systems that push water through membranes for additional safety. 

“If people are using a reverse osmosis system at their home, that will get rid of arsenic anyway,” he said.