King George County officials said monthly water samples taken April 14 from Oakland Park Waterworks—the public water system that last month was under alert—showed no evidence of bacteria. “It appears that we may never know how the E. coli entered the system,” said Christopher Werle, chairman of the King George County Service Authority, which owns the Oakland Park system and eight others in the county. Oakland Park Waterworks services about 330 customers, including Sealston Elementary School, the King George Industrial Park and Oakland Park subdivision. From March 24–29, customers were told it wasn’t safe to drink the water without boiling it or treating it with purification tablets. Water samples from two homes in the Oakland Park subdivision showed levels of E. coli, which usually means there’s been sewage or animal waste contamination. Werle said E. coli contamination usually is found in shallow private wells with little to no monitoring or safeguards. It rarely occurs in…