Public health officials have issued a drinking water warning to Jurupa Valley residents after a positive case of E. Coli was discovered at a local water source.  The warning remained in effect through the weekend but was lifted on Monday afternoon after tests found that there were no traces in the water. The positive test sample of the fecal indicator was found on Wednesday, according to the Jurupa Community Services District. Authorities say that the sample was found before disinfection took place and it was subsequently removed from the water system.  They also said that the sample was not found in the distribution system nor was it discovered in the treatment system, but rather in a contained water source.