On 28 June 2022 Conagua's director general, Germán Martínez Santoyo, said that industrial concession holders in Nuevo León would put 200 liters per second into Monterrey's municipal network, with a target of 500. Conagua counted 64 concession holders in Nuevo León holding close to 50 million cubic meters a year between them, roughly 1,600 liters per second, and named Ternium de México as the one supplying the most water at that point. Monterrey's metropolitan system needed 16,180 liters per second. Its dams were delivering 7,760.
The transfer was not a commercial negotiation. The Acuerdo de carácter general de inicio de emergencia por ocurrencia de sequía severa, extrema o excepcional en cuencas para el año 2022, published in the Diario Oficial de la Federación on 12 July 2022, set out the route. It relies on article 29 BIS 3, fracción VI of the Ley de Aguas Nacionales, which lets a concession holder cede volumes temporarily to the water authority while an emergency is declared.
That is the exposure this piece is about. A plant in Mexico does not buy water on a supply contract. It holds a federal concession title for a stated annual volume, recorded in the Registro Público de Derechos de Agua, and a separate discharge permit. Both are administrative instruments and both can be narrowed. The question to answer before the next dry season is what output does at a reduced allocation, and what reuse capex closes the gap.
What the Nuevo León episode established
Conagua published a partial conclusion of the 2022 drought emergency in the DOF on 16 December 2022, lifting it for basins that no longer met the severe, extreme or exceptional threshold in the Monitor de Sequía. The instrument did not disappear. It is a standing federal power that reactivates with the drought classification. A site in a stressed basin should treat a cession request as a recurring scenario rather than a one-off.
Two features of the 2022 round matter for planning. Volumes moved from private holders into the municipal network within weeks of the declaration, not over a budget cycle. And the largest contributors were the largest holders, so the sites with the most process water carried most of the reduction.
What a site actually holds under the Ley de Aguas Nacionales
Congress enacted the Ley de Aguas Nacionales, published in the DOF on 1 December 1992. Conagua administers that law. It does not write it, and the distinction matters when a site decides whether to contest a determination or renegotiate a volume.
The federal fee per cubic meter on extraction comes from article 223 of the Ley Federal de Derechos, and the rate depends on the zona de disponibilidad of the basin or aquifer the site draws from. Article 231 of that law sets four zones. Conagua published the assignments for fiscal year 2023 in the DOF on 31 March 2023. The Área Metropolitana de Monterrey aquifer is Zone 1, the scarcest and dearest band. Citrícola Norte, also in Nuevo León, is Zone 3.
Two plants in the same state can therefore carry different water costs for the same draw, and an administrative table sets the difference. Any serious view of industrial water management at a Mexican site starts with that table and with the REPDA record behind it.
Discharge is the second permit, and it changed in 2023
NOM-001-SEMARNAT-2021 was published in the DOF on 11 March 2022 and replaced NOM-001-SEMARNAT-1996. Its general limits became mandatory on 11 March 2023, and the specific parameter limits applied from 3 April 2023. Conagua issues the discharge permit and collects the federal derecho on discharges to national water bodies under the Ley Federal de Derechos. A site that met the 1996 norm was not automatically compliant in 2023, and the sampling record is what a verification tests. The rules on industrial water discharge sit alongside the concession, not inside it.
What Conagua is building, and what it does not change
Conagua reported on 31 May 2023 that 93.5 billion pesos had been invested across 15 federal water projects. Martínez gave progress on six of them. The Yaqui aqueduct stood at 45% and the Santa María dam in Sinaloa at 88%. El Zapotillo in Jalisco carried a total of 17.26 billion pesos, of which 7.646 billion had been exercised. Three were targeted for completion in December 2023, the Yaqui aqueduct, the Santa María dam and El Zapotillo.
Monterrey's project moved faster. The Gobierno de Nuevo León reported the inauguration of the El Cuchillo II aqueduct on 13 September 2023, at 93 kilometers and 12,244 million pesos, of which 5,701 million came from the state and 6,543 million from the federation. It opened at 1,500 liters per second in its first phase, against a design capacity of 5,000.
New conveyance raises municipal supply. It does not enlarge a private concession title, and it does not remove the cession mechanism from the statute. On our read, federal works change the probability of a curtailment rather than the consequence of one.
Reuse moves two cost lines and adds a third
Article 224, fracción II of the Ley Federal de Derechos exempts the use of wastewater from the extraction fee where the user gives up an equal proportion of other water, or where the effluent comes directly from urban or industrial collectors. Reuse therefore cuts the article 223 liability on the displaced volume, and it cuts the volume at risk in a cession.
It also adds electrical load. Reclaim pumping, aeration blowers and membrane trains run close to continuously, and they run through the peak hours. On a CFE Gran Demanda en Media Tensión Horaria supply, the capacity and distribution charges are billed on measured demand rather than on energy alone. A reuse case built on kWh understates the operating cost. Size the load, then re-check the billed demand it creates, before the capex goes to the board.
What the Ternium figure covers
Ternium announced a USD 3.2 billion investment at Pesquería, Nuevo León, reported by El Financiero on 21 June 2023. The money is for a new slab steel mill with cold rolling, hot rolling, galvanizing and pickling lines, rated at 2.6 million tonnes of cast steel, with start-up in the first half of 2026. The company said the whole of the process water for the new plant would come from treated wastewater for industrial use.
The 3.2 billion is the mill. It is not a water investment, and quoting it as one overstates what Mexican steel and metals operations spend on water by a wide margin. The narrower reading is the useful one. A new plant in a Zone 1 aquifer was designed around treated effluent because fresh concessioned volume was not a safe planning assumption in that basin.
What to confirm before the next dry season
Pull the REPDA record for every title the site holds and compare the concessioned annual volume against the past twelve months of metered draw. A site drawing well under title has room to cede. A site drawing at title has none.
Then model production at a reduced allocation. Use the reduction the site would face if a cession request arrived in the middle of a hot season, and price the lost tonnes or units. That number, not the water bill, is the exposure.
Check the discharge analyses against NOM-001-SEMARNAT-2021 rather than against the norm the permit was written under. Where the site fails a specific parameter, the treatment step that fixes it is often the same step that returns reuse volume. Cost the two together.
Check your site's water exposure before the next dry season
Send the REPDA concession title, twelve months of water and drainage invoices, the discharge analyses against the applicable NOM, and a process water balance. Mexico Energy Partners returns the concessioned volume against actual draw, the production loss at a reduced allocation, and the reuse or treatment options that close the gap, including the electrical load each one adds to contracted demand.
Sources
- Expansión Política, "Crisis de agua en NL: empresas acuerdan aportar 200 litros por segundo a la red", 28 June 2022.
- Diario Oficial de la Federación, "Acuerdo de carácter general de inicio de emergencia por ocurrencia de sequía severa, extrema o excepcional en cuencas para el año 2022", 12 July 2022.
- Diario Oficial de la Federación, "Acuerdo de carácter general de conclusión parcial de emergencia por sequía severa de cuencas en 2022", 16 December 2022.
- Diario Oficial de la Federación, Ley de Aguas Nacionales, 1 December 1992.
- Diario Oficial de la Federación, "Acuerdo por el que se dan a conocer las zonas de disponibilidad que corresponden a las cuencas y acuíferos del país para el ejercicio fiscal 2023", 31 March 2023.
- Ley Federal de Derechos, articles 223, 224 and 231, text in force for fiscal year 2023.
- Diario Oficial de la Federación, NOM-001-SEMARNAT-2021, 11 March 2022.
- La Jornada, "Se han invertido 93 mil 500 mdp en 15 grandes proyectos hídricos: Conagua", 31 May 2023.
- Gobierno del Estado de Nuevo León, "Inauguran Samuel García y Presidente López Obrador Acueducto El Cuchillo II", 13 September 2023.
- El Financiero, "Invertirá Ternium 3,200 mdd en Pesquería", 21 June 2023.
- CFE, published tariff schedule for Gran Demanda en Media Tensión Horaria.