Frequent Questions

Systems choosing to use membrane filtration to meet the additional Cryptosporidium treatment requirements under the Long Term 2 Enhanced Surface Water Treatment Rule (LT2) are required to conduct direct integrity tests on each membrane unit at a frequency

The LT2ESWTR requires that direct integrity testing be conducted on each membrane unit at least once each day that the membrane unit is in operation for rule compliance, even if the unit is operational for only a fraction of each day. It is also recommended, though not specifically required by the rule, that testing be conducted at approximately the same time each day in order to maintain a roughly consistent time interval. Public water system operators may only conduct this testing less frequently than daily with approval from the state. (Membrane Filtration Guidance Manual, EPA815-R-06-009; November 2005).
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