---
kind: "section"
citation: "40 C.F.R. § 141.171"
title: "40"
number: "141.171"
heading: "Criteria for avoiding filtration."
url: "https://uscodex.org/cfr/40/141.171"
---

# §141.171. Criteria for avoiding filtration.


In addition to the requirements of [§ 141.71](/cfr/40/141.71.md), a public water system subject to the requirements of this subpart that does not provide filtration must meet all of the conditions of paragraphs [(a)](#a) and [(b)](#b) of this section.

- (a) **Site-specific conditions.** In addition to site-specific conditions in [§ 141.71(b)](/cfr/40/141.71.md?p=b), systems must maintain the watershed control program under [§ 141.71(b)(2)](/cfr/40/141.71.md?p=b-2) to minimize the potential for contamination by Cryptosporidium oocysts in the source water. The watershed control program must, for Cryptosporidium:
  - (1) Identify watershed characteristics and activities which may have an adverse effect on source water quality; and
  - (2) Monitor the occurrence of activities which may have an adverse effect on source water quality.
- (b) During the onsite inspection conducted under the provisions of [§ 141.71(b)(3)](/cfr/40/141.71.md?p=b-3), the State must determine whether the watershed control program established under [§ 141.71(b)(2)](/cfr/40/141.71.md?p=b-2) is adequate to limit potential contamination by Cryptosporidium oocysts. The adequacy of the program must be based on the comprehensiveness of the watershed review; the effectiveness of the system's program to monitor and control detrimental activities occurring in the watershed; and the extent to which the water system has maximized land ownership and/or controlled land use within the watershed.

## Notes

### Source

Source: 63 FR 69516, Dec. 16, 1998, 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.