The Carlsbad Unified School District says repairs have been completed to purge contaminated drinking water at Hope Elementary School, which may have been present in the school's water system for several months.
In a statement issued Monday, the district said that there were "sporadic reports" of water discoloration shortly after the school reopened in the fall. In November, more complaints were lodged regarding the color, taste and smell of the water, though testing did not indicate the water was unsafe, the district said.
Following further investigation, which concluded that no E. coli or other harmful bacteria was found in the water, the district shut off water at the campus last Thursday after concluding that domestic water lines at the school were crossed with reclaimed water irrigation lines on campus.
According to the district, the cause of the cross-connection remains under investigation, though it said "it appears that this happened during the course of construction based on the timing of complaints and the location of the cross-connection."
City crews have since purged the system with highly chlorinated water, then flushed out the chlorinated water with potable water. The school's drinking water dispenser filters have also been replaced.
Following the repairs, the city conducted further water testing, which was reviewed by the county of San Diego before the school was reopened Monday, the district says. No similar reports have occurred at other district schools, but the city is conducting cross-connection testing at Kelly and Magnolia elementary schools as a precaution.
In a Frequently Asked Questions document issued for parents, the district says reclaimed water contains "higher levels of salts, dissolved minerals, nitrogen and phosphorus than drinking water," but stressed that it is treated and disinfected, per EPA guidelines aimed at keeping biological contaminants "to a safe minimum."
The FAQ states that per the State Water Resources Control Board, parents whose children exhibit symptoms of a stomach or intestinal illness should seek medical attention.
The district says that when it received the initial complaints, construction teams said the issue was merely aesthetic and would be resolved by flushing the system. It also emphasized that testing results did not initially indicate anything was amiss, though subsequent test results indicated increased levels of chlorine, water hardness and alkaline content.
"We are sincerely sorry that this was not reported earlier," the district said in its statement. "We relied on the reports and information from our contractors, construction and bond program managers that the water had been tested for safety, that the issue was aesthetic, and would resolve. We did not anticipate the cause of the problem, and we regret that we did not discover the cause sooner. Once we were alerted to the cause, we took all the steps necessary to prevent further exposure; to inform our community; and to resolve the problem."
