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CORRECTIVE ACTIONS AFTER TREATMENT VESSELq PRESSURE TANK and STROGAE TANK COMPONENT INVESTIGATION : Correct all identified structural deficiencies that allowed the entrance of bacteria.. After the corrections have been achieved, disinfect the effected vessel , tank, and water line connections between the effected component and the system , per the AWWA Standards , using NSF 61 approved chlorine. Effective disinfection of a pressure tank and storage tank includes the removal of sediment and flushing clear of all debris, before applying a 200 ppm chlorine solution to all surfaces of the vessel/tank. Once all surfaces have been washed with the solution , fill the vessel/tank to overflow level with a solution of 50 ppm and hold for 6-24 hours. After two hours of contact time with the disinfectant, sample the vessel/tank for the chlorine residual. If the residual tests below 50 ppm , increase the concentration to 50 ppm . A successful disinfection requires a residual of at least 10 ppm to be present after the 6-24 hours. If the chlorine residual is found to be non-detectable, then the disinfection process may not have been successful. Repeat the cleaning and disinfection process. The media in an effected vessel shall be disinfected per the manufacturer's specifications to eliminate the presence of bacteria in the media and vessel. The contaminated media may be removed from the vessel and appropriately disposed of or reconditioned per the manufacturer's specifications . The empty effected vessel is then disinfected (Le. initial contact with a solution of 200 ppm chlorine residual and then filled to overflow levels with 50 ppm for 6-24 hours). The vessel may be re-bedded with new media, after the vessel tests TC absent with <0 . 05 ppm chlorine residuals. Resample the disinfected component by directing your laboratory to collect samples and test for non-detect chlorine residuals and absence of TC bacteria using enumeration test methods, before connecting the components to the system. If the COMPONENT Continues to Fails: Contact the EHD for guidance at (209) 468-3420. DISTRIBUTION SYSTEM INVESTIGATION: Review the REPEAT results above. Of these results, which sample location is positive with the highest MPN count? Have your laboratory collect additional "Other" TC samples up stream and down stream of the site (with the highest MPN) to find where the system begins to test TC positive and the highest MPN count, within the system. These "Other" results will ID where bacteria are entering into the system . Inspect the system , looking critically up stream and down stream of the site with the highest MPN and review the history of the s stem for the possible cause of the TCR MCL as noted below. DISTRIBUTION SYSTEM SYSTEM RESPONSES What is the minimum pressure you are maintaining in the distributions stem? Must operate system at pressures > 20 psi at all times. Has the distribution system been worked on within the last week? (taps, hydrant flushing , main breaks, mainline extensions, etc.) If yes, provide details. YIN Are there any signs of excavations near your distribution system not under the direct control of your maintenance staff? YIN On what date was the distribution system last flushed? Is there a written flushing procedure you can provide for our review? YIN Investigate for backflow devices that have been removed that shouldn't have, that need repair, need to be installed or installed properly. Ensure all testable backflow devices are functioning by a Certified tester after being repaired or installed . Have the backflow devices been tested this year? If N , then have them tested now by a certified tester. Have the backflow devices been inspected for leaks, damage, or presence this month? YIN On what date was the system last surveyed to identify cross connections? Is the ground wet in an area that has not been irrigated? YIN Are the water meter readings indicating higher than normal water usage? YIN Could indicate a water line break. Has anyone connected to the system with: a high pressure washer, a neighboring water system, RV, a water tank, or a hose used to fill apool/tank? YIN If Y, note date of the event. Did the system experience a drop of pressure below 5 psi? (evidence of dirty water, no water, power outage, pump failure, break ih a water line, was system water used for an event that used more water then normal) If Y, note date of the event. YIN Was system or portion of the system (building, home, RV) not used for a while, then resumed normal water usage or experience a drop of pressure as described in box above)? If Y, note date YIN