The city of Alamo Heights' water system says a raw ground water source sample has tested positive for E. coli.
According to a statement issued by the city on Wednesday morning, wells No. 3 and 7, in the 6100 block of Broadway at the city facilities.
The wells were immediately removed from service and a boil water notice has not been issued.
The wells produce raw water, which is groundwater from a well before being treated and disinfected, and before entering the distribution system.
All raw water is treated and disinfected before entering the distribution system as finished water for human consumption, Alamo Heights officials said in the statement.