Key takeaways
CONAGUA published the values that determine national water availability zones for 2026.
These variables directly affect the calculation of fees under the Federal Law of Fees.
Changes in classification may result in significant increases or adjustments in the tax burden
On February 27, 2026, SEMARNAT published in the Official Gazette of the Federation the Agreement announcing the values of each of the variables that make up the formulas for determining, during fiscal year 2026, the availability zones referred to in sections I and II of Article 231 of the Federal Law of Fees, effective as of January 1, 2014 (the “Agreement”). This update is particularly relevant for concessionaires and assignees of national waters, since the availability zone assigned to a supply source is one of the central elements for calculating federal rights for the use, exploitation, or utilization of national waters.
The Agreement does not modify the methodology, but rather updates the technical values that feed into the formulas provided for in the Federal Law of Fees to determine water availability, which in practice may change the classification applicable to each user, depending on the type of body and mechanism of use:
- Surface water: availability is determined by hydrological basin, considering variables such as runoff, returns, imports, extraction, and evaporation.
- Groundwater: availability is calculated by aquifer, based on average annual availability, recharge, and committed natural discharge.
Based on these values, the availability zone corresponding to each water body is defined, which directly affects the applicable quota for the payment of rights.
Consequently, even though there are no regulatory changes per se, the updating of variables may have significant economic effects, particularly for users with high concession volumes, by modifying the basis on which their tax burden is calculated in 2026.
Full text of the Agreement available here.
Next steps
- Identify the basin or aquifer through which water is supplied.
- Confirm the applicable availability zone in 2026.
- Model the impact on the calculation of fees.
- Anticipate budget adjustments or regulatory optimization strategies.
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