---
kind: "unit"
title: "40"
title_heading: "Protection of Environment"
key: "chI/subchD/part141"
level: "part"
label: "Part 141"
heading: "National Primary Drinking Water Regulations"
release: "ecfr-current"
date: "2026-08-27"
url: "https://uscodex.org/cfr/40/chI-subchD-part141"
sections_count: 199
---

# Part 141 — National Primary Drinking Water Regulations

Title 40 C.F.R. — Protection of Environment › Chapter I — Environmental Protection Agency › Subchapter D — Water Programs

## Contents

- [Subpart A — General](/cfr/40/chI-subchD-part141-subpartA.md)
- [Subpart B — Maximum Contaminant Levels](/cfr/40/chI-subchD-part141-subpartB.md)
- [Subpart C — Monitoring and Analytical Requirements](/cfr/40/chI-subchD-part141-subpartC.md)
- [Subpart D — Reporting and Recordkeeping](/cfr/40/chI-subchD-part141-subpartD.md)
- [Subpart E — Special Regulations, Including Monitoring](/cfr/40/chI-subchD-part141-subpartE.md)
- [Subpart F — Maximum Contaminant Level Goals and Maximum Residual Disinfectant Level Goals](/cfr/40/chI-subchD-part141-subpartF.md)
- [Subpart G — National Primary Drinking Water Regulations: Maximum Contaminant Levels and Maximum Residual Disinfectant Levels](/cfr/40/chI-subchD-part141-subpartG.md)
- [Subpart H — Filtration and Disinfection](/cfr/40/chI-subchD-part141-subpartH.md)
- [Subpart I — Control of Lead and Copper](/cfr/40/chI-subchD-part141-subpartI.md)
- [Subpart J — Use of Non-Centralized Treatment Devices](/cfr/40/chI-subchD-part141-subpartJ.md)
- [Subpart K — Treatment Techniques](/cfr/40/chI-subchD-part141-subpartK.md)
- [Subpart L — Disinfectant Residuals, Disinfection Byproducts, and Disinfection Byproduct Precursors](/cfr/40/chI-subchD-part141-subpartL.md)
- [Subpart M-N — Subparts M-N [Reserved]](/cfr/40/chI-subchD-part141-subpartM-N.md)
- [Subpart O — Consumer Confidence Reports](/cfr/40/chI-subchD-part141-subpartO.md)
- [Subpart P — Enhanced Filtration and Disinfection—Systems Serving 10,000 or More People](/cfr/40/chI-subchD-part141-subpartP.md)
- [Subpart Q — Public Notification of Drinking Water Violations](/cfr/40/chI-subchD-part141-subpartQ.md)
- [Subpart R — Subpart R [Reserved]](/cfr/40/chI-subchD-part141-subpartR.md)
- [Subpart S — Ground Water Rule](/cfr/40/chI-subchD-part141-subpartS.md)
- [Subpart T — Enhanced Filtration and Disinfection—Systems Serving Fewer Than 10,000 People](/cfr/40/chI-subchD-part141-subpartT.md)
- [Subpart U — Initial Distribution System Evaluations](/cfr/40/chI-subchD-part141-subpartU.md)
- [Subpart V — Stage 2 Disinfection Byproducts Requirements](/cfr/40/chI-subchD-part141-subpartV.md)
- [Subpart W — Enhanced Treatment for Cryptosporidium](/cfr/40/chI-subchD-part141-subpartW.md)
- [Subpart X — Aircraft Drinking Water Rule](/cfr/40/chI-subchD-part141-subpartX.md)
- [Subpart Y — Revised Total Coliform Rule](/cfr/40/chI-subchD-part141-subpartY.md)
- [Subpart Z — Control of Per- and Polyfluoroalkyl Substances (PFAS)](/cfr/40/chI-subchD-part141-subpartZ.md)