A routine well test found E. coli and now the San Antonio Water System has shut down the source of that problem.
SAWS said a westside well tested positive for E. coli bacteria.
The well is located at the corner of Tippecanoe and Filmore.
SAWS said it immediately shut the well down and transferred about 19,000 customers to other SAWS water wells.
No service has been affected.
SAWS said the well is one of the former Bexar Met wells taken over by SAWS.
They said state rules require further testing, and that is now being done.
Until then, the well is cut off from the rest of the SAWS system, and crews will work to flush it out.