40 CFR § 141.531 - What criteria must a State use to determine that a profile is unnecessary?

---
identifier: "/us/cfr/t40/s141.531"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 141.531 - What criteria must a State use to determine that a profile is unnecessary?"
title_number: 40
title_name: "Protection of Environment"
section_number: "141.531"
section_name: "What criteria must a State use to determine that a profile is unnecessary?"
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "D"
subchapter_name: "WATER PROGRAMS"
part_number: "141"
part_name: "NATIONAL PRIMARY DRINKING WATER REGULATIONS"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
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."
regulatory_source: "40 FR 59570, Dec. 24, 1975, unless otherwise noted."
cfr_part: "141"
---


# 141.531 What criteria must a State use to determine that a profile is unnecessary?

States may only determine that a system's profile is unnecessary if a system's TTHM and HAA5 levels are below 0.064 mg/L and 0.048 mg/L, respectively. To determine these levels, TTHM and HAA5 samples must be collected after January 1, 1998, during the month with the warmest water temperature, and at the point of maximum residence time in your distribution system. Your State may approve a more representative TTHM and HAA5 data set to determine these levels.

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