Your system must meet two strengthened combined filter effluent turbidity limits.
(a) The first combined filter effluent turbidity limit is a “95th percentile” turbidity limit that your system must meet in at least 95 percent of the turbidity measurements taken each month. Measurements must continue to be taken as described in § 141.74(a) and (c). Monthly reporting must be completed according to § 141.570. The following table describes the required limits for specific filtration technologies.
| If your system consists of * * * | Your 95th percentile turbidity value is * * * |
|---|---|
| (1) Conventional Filtration or Direct Filtration | 0.3 NTU. |
| (2) All other “Alternative” Filtration | A value determined by the State (not to exceed 1 NTU) based on the demonstration described in § 141.552. |
(b) The second combined filter effluent turbidity limit is a “maximum” turbidity limit which your system may at no time exceed during the month. Measurements must continue to be taken as described in § 141.74(a) and (c). Monthly reporting must be completed according to § 141.570. The following table describes the required limits for specific filtration technologies.
| If your system consists of * * * | Your maximum turbidity value is * * * |
|---|---|
| (1) Conventional Filtration or Direct Filtration | 1 NTU. |
| (2) All other “Alternative Filtration” | A value determined by the State (not to exceed 5 NTU) based on the demonstration as described in § 141.552. |
[67 FR 1839, Jan. 14, 2002, as amended at 69 FR 38856, June 29, 2004]