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 Part 136 methods, some approved industry-specific methods are published or incorporated by reference at 40 CFR Parts 401 through 503.