Frequent Questions

When you refer to ?inactivation credits? or ?log credits,? do we use the same contact time (CT) tables as for Giardia-virus removal or are there Crypto-specific CT tables?

There are Crypto-specific inactivation tables for ozone, chlorine dioxide, and UV light.  These tables provide the credits for Crypto removal requirements.  The CT tables for other rules have not changed.

For additional guidance on the Long Term 2 Enhanced Surface Water Treatment Rule please visit

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