---
kind: "section"
citation: "40 C.F.R. § 141.551"
title: "40"
number: "141.551"
heading: "What strengthened combined filter effluent turbidity limits must my system meet?"
url: "https://uscodex.org/cfr/40/141.551"
---

# §141.551. What strengthened combined filter effluent turbidity limits must my system meet?


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)](/cfr/40/141.74.md?p=a) and [(c)](/cfr/40/141.74.md?p=c). Monthly reporting must be completed according to [§ 141.570](/cfr/40/141.570.md). The following table describes the required limits for specific filtration technologies.
- (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)](/cfr/40/141.74.md?p=a) and [(c)](/cfr/40/141.74.md?p=c). Monthly reporting must be completed according to [§ 141.570](/cfr/40/141.570.md). The following table describes the required limits for specific filtration technologies.

## Notes

### Amendments

[67 FR 1839, Jan. 14, 2002, as amended at 69 FR 38856, June 29, 2004]

### Source

Source: 67 FR 1839, Jan. 14, 2002, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 300f, 300g-1, 300g-2, 300g-3, 300g-4, 300g-5, 300g-6, 300j-4, 300j-9, and 300j-11.

### Source

Source: 40 FR 59570, Dec. 24, 1975, unless otherwise noted.

### Amendments

[67 FR 1839, Jan. 14, 2002, as amended at 69 FR 38856, June 29, 2004]