Approved CWA Chemical Test Methods
The analytical methods promulgated under Clean Water Act section 304(h) are sometimes referred to as the "304(h)" or "Part 136" methods. The methods measure chemical and biological pollutants in media, such as wastewater, ambient water, sediment, and biosolids (sewage sludge). These various CWA methods are tested in a variety of labs and matrices.
In addition to 40 CFR Part 136 methods, some approved industry-specific methods are published or incorporated by reference at 40 CFR Parts 401 through 503.
On this page:
- Approved methods listed by method number
- Approved methods listed by analyte (reference tables in 40 CFR 136.3)
Approved Methods Listed by Method Number
| Number | Method Title |
|---|---|
| 120.1 | Conductance (Specific Conductance, μmhos, 25°C) by Conductivity Meter |
| 130.1 | Hardness, Total (mg/L as CaCO3) (Colorimetric, Automated EDTA) by Spectrophotometer |
| 150.2 | pH, Continuous Monitoring (Electrometric) by pH Meter |
| 160.4 | Residue, Volatile (Gravimetric, Ignition at 550°C) by Muffle Furnace |
| 180.1 | Turbidity by Nephelometry Revision 2.0 |
| 300.0 | Inorganic Anions by Ion Chromatography Revision 2.1 |
| 300.1 | Inorganic Anions in Drinking Water by Ion Chromatography Revision 1.0 |
| 310.2 | Alkalinity, Colorimetric, Automated Methyl Orange |
| 335.4 | Total Cyanide by Semi-Automated Colorimetry Revision 1.0 |
| 350.1 | Ammonia Nitrogen by Semi-Automated Colorimetry Revision 2.0 |
| 351.1 | Total Kjeldahl Nitrogen (Colorimetric, Automated Phenate) by Autoanalyzer |
| 351.2 | Total Kjeldahl Nitrogen by Semi-Automated Colorimetry Revision 2.0 |
| 352.1 | Nitrogen, Nitrate (Colorimetric, Brucine) by Spectrophotometer |
| 353.2 | Nitrate-Nitrite by Automated Colorimetry Revision 2.0 |
| 365.1 | Phosphorus by Semi-Automated Colorimetry Revision 2.0 |
| 365.3 | Phosphorus, All Forms, Colorimetric, Ascorbic Acid, Two Reagent |
| 365.4 | Phosphorus, Total, Colorimetric, Automated, Block Digester, Automated Analyzer II |
| 375.2 | Sulfate by Automated Colorimetry Revision 2.0 |
| 410.3 | Chemical Oxygen Demand (Titrimetric, High Level for Saline Waters) by Titration |
| 410.4 | Chemical Oxygen Demand by Semi-Automated Colorimetry Revision 2.0 |
| 1627 | Kinetic Test Method for the Prediction of Mine Drainage Quality |
| OIA-1677-09 | Available Cyanide by Ligand Exchange and Flow Injection Analysis (FIA) • Regulatory history |
| Number | Method Title |
|---|---|
| 200.2 | Sample Preparation Procedure for Spectrochemical Determination of Total Recoverable Elements Revision 2.8 |
| 200.5 | Trace Elements in Drinking Water by Axially Viewed Inductively Coupled Plasma-Atomic Emission Spectrometry Revision 4.2 |
| 200.7 | Metals and Trace Elements in Water and Wastes by Inductively Coupled Plasma-Atomic Emission Spectrometry Revision 4.4 |
| 200.8 | Trace Elements in Water and Wastes by Inductively Coupled Plasma-Mass Spectrometry Revision 5.4 |
| 200.9 | Trace Elements by Stabilized Temperature Graphite Furnace Atomic Absorption Spectrometry Revision 2.2 |
| 206.5 | Arsenic, Sample Digestion Prior to Total Arsenic Analysis by Silver Diethyldithiocarbamate or Hydride Procedures |
| 218.6 | Dissolved Hexavalent Chromium in Drinking Water, Groundwater, and Industrial Wastewater by Ion Chromatography Revision 3.3 • Regulatory history |
| 231.2 | Gold, Atomic Absorption, Furnace Technique |
| 235.2 | Iridium, Atomic Absorption, Furnace Technique |
| 245.1 | Mercury in Water by Cold Vapor Atomic Absorption Spectrometry Revision 3.0 |
| 245.2 | Mercury, Cold Vapor Technique, Automated |
| 245.7 | Mercury in Water by Cold Vapor Atomic Fluorescence Spectrometry Revision 2.0 • Regulatory history |
| 252.2 | Osmium, Atomic Absorption, Furnace Technique |
| 253.2 | Palladium, Atomic Absorption, Furnace Technique |
| 255.2 | Platinum, Atomic Absorption, Furnace Technique |
| 265.2 | Rhodium, Atomic Absorption, Furnace Technique |
| 267.2 | Ruthenium, Atomic Absorption, Furnace Technique |
| 279.2 | Thallium, Atomic Absorption, Furnace Technique |
| 283.2 | Titanium, Atomic Absorption, Furnace Technique |
| 289.2 | Zinc, Atomic Absorption, Furnace Technique |
| 1631E | Mercury in Water by Oxidation, Purge and Trap, and Cold Vapor Atomic Fluorescence Spectrometry Revision E • Regulatory history |
| Number | Method Title |
|---|---|
| 420.1 | Phenolics, Total Recoverable, Spectrophotometric, Manual 4-AAP With Distillation |
| 420.4 | Total Recoverable Phenolics by Semi-Automated Colorimetry Revision 1.0 |
| 525.1 | Organic Compounds in Drinking Water by Liquids-Solid Extraction and Capillary Column Gas Chromatography/Mass Spectrometry Revision 2.2 |
| 525.2 | Organic Compounds in Drinking Water by Liquid-Solid Extraction and Capillary Column Gas Chromatography/Mass Spectrometry Revision 2.0 |
| 601 | Purgeable Halocarbons |
| 602 | Purgeable Aromatics |
| 603 | Acrolein and Acrylonitrile |
| 604 | Phenols |
| 605 | Benzidines |
| 606 | Phthalate Ester |
| 607 | Nitrosamines |
| 608 | Organochlorine Pesticides and PCBs |
| 608.1 | Organochlorine Pesticides in Municipal and Industrial Wastewater |
| 608.2 | Certain Organochlorine Pesticides in Municipal and Industrial Wastewater |
| 609 | Nitroaromatics and Isophorone |
| 610 | Polynuclear Aromatic Hydrocarbons |
| 611 | Haloethers |
| 612 | Chlorinated Hydrocarbons |
| 613 | 2,3,7,8-Tetrachloro Dibenzo-p-Dioxin |
| 614 | Organophosphorus Pesticides in Municipal and Industrial Wastewater |
| 614.1 | Organophosphorus Pesticides in Municipal and Industrial Wastewater |
| 615 | Chlorinated Herbicides in Municipal and Industrial Wastewater |
| 617 | Organohalide Pesticides and PCBs in Municipal and Industrial Wastewater |
| 619 | Triazine Pesticides in Municipal and Industrial Wastewater |
| 622 | Organophosphorus Pesticides in Municipal and Industrial Wastewater |
| 622.1 | Thiophosphate Pesticides in Municipal and Industrial Wastewater |
| 624 | Purgeables |
| 625 | Base/Neutrals and Acids |
| 632 | Carbamate and Urea Pesticides in Municipal and Industrial Wastewater |
| 1613B | Tetra- through Octa-Chlorinated Dioxins and Furans by Isotope Dilution HRGC/HRMS Revision B • Regulatory History |
| 1624B | Volatile Organic Compounds by Isotope Dilution GC/MS |
| 1625B | Semivolatile Organic Compounds by Isotope Dilution GC/MS |
| 1664A | n-Hexane Extractable Material (HEM; Oil and Grease) and Silica Gel Treated n-Hexane Extractable Material (SGT-HEM; Non-polar Material) by Extraction and Gravimetry Revision A • Regulatory history |
| 1664B | n-Hexane Extractable Material (HEM; Oil and Grease) and Silica Gel Treated n-Hexane Extractable Material (SGT-HEM; Non-polar Material) by Extraction and Gravimetry Revision B • Regulatory history |
Approved Methods Listed by Analyte
The lists of approved methods at 40 CFR 136.3, with footnotes, are provided here as a reference. To download specific method publications, refer to the tables above.
- Lists of methods by analyte; from 40 CFR 136.3
- IB: Inorganics
- IC: Non-pesticide organics
- ID: Pesticides
- IF: Pharmaceutical
- IG: Pesticide active ingredients