March 15, 2022

NOM-001-SEMARNAT-2021 Limits Wastewater Pollutants in Mexico

Holland & Knight Alert
Rodolfo Rueda | Adrián Ortiz de Elguea

The Mexican Environmental and Natural Resources Ministry (Secretaria de Medio Ambiente y Recursos Naturales or SEMARNAT) published the NOM-001-SEMARNAT-2021 in the Federal Official Gazette on March 11, 2022. The NOM-001-SEMARNAT 2021 establishes the permissible limits for pollutants in wastewater discharge in receiving bodies owned by the nation.


The NOM-001-SEMARNAT-2021 has replaced the NOM-001-SEMARNAT-1996, which was issued 25 years ago and had not been modified since that date. It is important to note that this document will be mandatory for those responsible for wastewater discharges on any type of receiving bodies owned by the nation as of its entry into force on March 11, 2023, one year after its publication, with exception of the following:

  • permissible limits parameters (will become effective on April 3, 2023)
  • permissible limits parameters on real color and toxicity (will become effective as of the fourth year from the publication date of the NOM-001-SEMARNAT-2021)


NOM-001-SEMARNAT-2021 mainly modifies the classification of the wastewater discharge receiving bodies, strengthening the permissible limits. It also updates the specifications, taste methods, sampling, temperature parameters, toxicity measurement, assessment procedures, and approach to subsequent uses to improve the management and protection of water bodies, as well as the international standards.

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