The old Public Registry of Water Rights (REPDA) isn't called that anymore: since 12 December 2025, when Mexico's new General Water Law and the reforms to the National Water Law took effect, it became the National Public Water Registry (REPNA). It records concession titles, assignment titles and discharge permits, along with any changes to their characteristics. Separately from the registry, any company holding a valid title must declare and pay the fee for the use or exploitation of national waters every quarter to Mexico's tax authority (SAT), based on its meter readings.
What changed: from REPDA to REPNA
The decree enacting the General Water Law and reforming the National Water Law was published in the Official Gazette of the Federation (DOF) on 11 December 2025 and took effect the following day, 12 December 2025. The reformed National Water Law itself defines the REPNA, in Article 3, section XLIV, as the registry that provides information and legal certainty to users of national waters and inherent assets, through the recording of concession titles, assignment titles and discharge permits, as well as any changes made to their characteristics.
Administration of the registry stays with Mexico's National Water Commission (CONAGUA): Article 9, section XX, empowers the Commission to issue titles and keep the registry, and Article 12 BIS 2, section V, also empowers the River Basin Organisations (Organismos de Cuenca) to issue titles and record them.
The reform isn't just a name change. It eliminates three arrangements that existed under the previous regime: the transfer of water rights between private parties, the provisional supply of concessioned water to third parties, and changing the use originally granted under a concession. If your company relied on buying water rights from another titleholder, or on receiving provisional supply from someone else's concession, that route no longer exists under the new framework. The decree also anticipates streamlined mechanisms for reassigning titles, though the operational details are still pending a subsequent regulation.
To renew a title, the application must be filed within the last three years of its validity and no later than six months before it expires. Missing that window is the costliest mistake a company with an industrial concession can make: letting the deadline pass means starting a new title process from scratch, with the risk that water availability in that basin may have changed in the meantime.
What your company declares and pays: water rights
Separately from the registry, using national waters creates a recurring tax obligation. Mexico's Federal Duties Law, in Article 226, states that the taxpayer calculates the water duty quarterly and pays it no later than the last business day of January, April, July and October. The calculation is based on the volume of water used or exploited during each quarter, determined from meter readings taken at period end, and the filing is made at offices authorised by the tax authority (SAT), not directly with CONAGUA.
Besides this use-and-exploitation duty, the Federal Duties Law separately regulates duties for wastewater discharge. If your facility discharges into a national receiving body, confirm the applicable chapter and frequency in the current text of the Federal Duties Law before setting an internal calendar: we weren't able to verify a single fixed schedule here for that duty, distinct from the use-and-exploitation one.
What your company should have in place
- A valid concession or assignment title, recorded in the REPNA, for every point where the facility extracts national water.
- Calibrated meters at every extraction point, since the quarterly declaration is based on their readings, not an estimate.
- An internal calendar with the four filing dates: the last business day of January, April, July and October.
- An expiry alert on the title, with enough lead time to file the renewal within the window running from three years to six months before expiry.
- A review of the declared use on the title, since the new framework removes the option of changing the water's originally granted use without a formal process.
This filing sits alongside the rest of the environmental obligations a company in Mexico may carry, and it's worth coordinating with whoever handles the Annual Operations Report and the RETC filing, since all three ask for water data that should be consistent with each other.
If your company doesn't hold its own concession
Not every plant extracts water directly from a national source. Many operate on supply from the municipal water utility, which holds the assignment title with CONAGUA and passes the duty's cost through the tariff it bills the company. In that case, your company doesn't appear as a titleholder in the REPNA, but you still have two fronts to manage: the consumption billed by the utility, which is the starting point for your water footprint, and wastewater discharge into the municipal network or a receiving body, which may need its own permit depending on flow and pollutant load. More and more industrial companies are also exploring industrial water reuse precisely to reduce dependence on a concession title that, under the new law, can no longer be transferred or provisionally lent between private parties.
How this connects to corporate water footprint
The volume you declare quarterly to the SAT is, in fact, the same starting data you need to measure your company's water footprint: water withdrawn by source, with its unit and period. The difference is that the tax filing ends once the duty is paid, while corporate water footprint work goes further, classifying that consumption by water type, cross-referencing it against the basin's water stress, and increasingly reporting it to customers or investors. For a company with several plants across different basins, having both exercises draw on the same meter data avoids calculating the same thing twice under two different criteria, something we cover in more detail in our guide to water footprint in Mexico.
Frequently asked questions
What is the REPNA and how does it differ from the REPDA?
The REPNA is the National Public Water Registry, the name that replaced the Public Registry of Water Rights (REPDA) as of 12 December 2025, under the new General Water Law and the reform of the National Water Law. Its function is the same, recording concession, assignment and discharge-permit titles, but under the new legal framework.
Do I need a concession title to use water at my plant?
Yes, if you withdraw national waters from your own point (a well, a river, a national water body). The corresponding concession or assignment title must be recorded in the REPNA.
How often do I declare and pay water duties?
Quarterly, no later than the last business day of January, April, July and October, under Article 226 of the Federal Duties Law, based on your meter readings.
Can I transfer my concession to another company in the group?
The reform that took effect on 12 December 2025 eliminates the transfer of water rights between private parties as it existed under the previous regime. It's worth reviewing the regulation and the reassignment mechanisms the reform itself anticipates in detail, rather than assuming a transfer remains possible on the same terms.
What happens if I miss the deadline to renew my title?
The renewal application must be filed within the last three years of validity and no later than six months before expiry. Outside that window, the company has no margin left to renew and would have to apply for a new title.
What if my plant uses water from the municipal utility, not its own concession?
You don't need to register in the REPNA or file the quarterly use-and-exploitation duty: that's the utility's responsibility, which it passes through in your water bill. It's still worth checking whether your discharge into the municipal network needs its own permit, and using your billed consumption as the basis for your water footprint.
Does the reform affect titles that were already granted before December 2025?
Existing titles remain the reference point for the company's water rights, but the registry they're recorded in changed name and legal basis, and the rules around transfers, provisional supply and renewal windows now follow the new law. It's worth checking an existing title's status directly against the REPNA rather than assuming nothing changed.
Keeping the title valid, the meters calibrated and the quarterly declaration current is the foundation any serious water footprint exercise is built on. Our water footprint solution starts from that same withdrawal-by-source data so you don't have to capture it twice.
