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As of September 29, 2026, a gate valve classified under tariff item 8481.80.04 does not enter Mexico without proof of compliance with NOM-012-CONAGUA-2021 at the point of entry. The Friday before, the same valve crossed without that document. Between one day and the next, only one thing changed: the NOM annex.
On September 28, 2026, the Secretaría de Economía (Mexico's economy ministry) published in the DOF (Diario Oficial de la Federación, the federal gazette) an acuerdo amending its Reglas y criterios de carácter general en materia de comercio exterior. The instrument has one operative article and one transitory article. The operative article replaces item 1 of Anexo 2.4.1, the table that lists the fracciones arancelarias (Mexican tariff items) whose goods must demonstrate compliance with a Norma Oficial Mexicana, or NOM, on entry into the country. The transitory article sets two effective dates: the day after publication for most of the entries, and 30 business days later for the entries covering mobile terminal equipment.
That staggered timing is what will trip up more than one trade compliance team this week. Two of the four standards involved already apply. The other two carry a November date. Reading the acuerdo as "this takes effect in November" leaves 31 tariff items uncovered from tomorrow.
What Anexo 2.4.1 requires, and what this amendment does
Anexo 2.4.1 of the SE's rules cross-references two lists: tariff items from the LIGIE, Mexico's tariff schedule, and NOMs. When a tariff item appears in the table with a NOM in the scope column, goods classified under that item must prove compliance with that standard at the point of entry, as a non-tariff regulation, before the pedimento (Mexico's customs declaration) is paid and the goods are released. Proof takes the form of a certificate or statement of conformity issued by a certification body accredited and approved for that NOM, declared on the pedimento through the corresponding identifier in Apéndice 8 of Anexo 22 of the RGCE.
The September 28 amendment adds 36 tariff-item-to-NOM entries to item 1, spread across four standards.
NOM-012-CONAGUA-2021, faucets, valves and fittings for potable water plumbing. 25 tariff items. It covers PVC pipe and flexible tubing in Chapter 39 (3917.23.04, 3917.31.01, 3917.32.91, 3917.39.99), washbasin and sink sets sold with a faucet or hoses (3922.10.01, 3922.90.99, 6910.10.01, 7324.10.01), hoses with fittings in Chapter 40 (4009.22.05, 4009.32.05, 4009.42.03), metal hoses (8307.10.99), and the heaviest block, in heading 8481: check valves (8481.30.01, 8481.30.99), valves under 8481.40.99, and thirteen items across 8481.80 and 8481.90 that run from gate and three-way valves to parts of sanitary faucets.
NOM-033-ENER-2019, energy efficiency of air-cooled AC motors. 6 tariff items in heading 8501: 8501.10.10, 8501.20.05, 8501.40.08, 8501.40.99, 8501.51.02 and 8501.51.99. The standard covers motors from 1 W to under 180 W, 2, 4 and 6 poles, squirrel-cage induction and electronically commutated, at a rated voltage of up to 240 V.
NOM-221/2-SCFI-2018, mobile terminal equipment on the 700, 800, 850, 1900, 1700/2100 and 2500 MHz bands. 5 tariff items: 8517.13.01 (smartphones), 8517.14.91 (other mobile phones), 8517.18.99, 8517.62.17 (apparatus for the reception, conversion, transmission or regeneration of voice, image or data, including switching and routing apparatus) and 8517.69.99.
NOM-221-SCFI-2017, IMEI code and FM receiver in mobile terminal equipment. 1 tariff item, 8517.18.99, which with this amendment now carries both parts of NOM-221.
The recitals of the acuerdo give the same reason for all four standards: goods classified under these tariff items were already within the scope of the NOM, but the tariff item was missing from the annex, and that omission left a regulatory gap at the point of entry. The obligation to comply already existed for anyone manufacturing or selling in Mexico. What closes on September 29 is the door through which those goods entered without demonstrating it at customs.
The dates that matter, in order
The acuerdo was signed on September 15, 2026 and published in the DOF thirteen days later, on Monday, September 28. Under its single transitory article, it takes effect the day after publication. That means that on Tuesday, September 29, the 25 faucet-and-valve items and the 6 motor items already require a NOM at the point of entry. The date that decides which non-tariff regulations apply to a shipment sits in Article 56, fracción I, of the Ley Aduanera: the date the goods cross the border by land, the date the vessel anchors, or the date the aircraft arrives. A container that anchored at Manzanillo on Friday the 25th falls under the previous table even if its pedimento is paid this week. The truck crossing at Nuevo Laredo on Tuesday the 29th falls under the new one. If your operation files consolidated pedimentos or clears under advance filing, confirm with your customs broker which date governs in your case.
For the two NOM-221 standards, the transitory article opens a 30-business-day window. The Secretaría de Economía published in the DOF of December 18, 2025 the acuerdo listing the days it does not treat as business days in 2026, and in the stretch that matters here it lists November 2 and the third Monday of November, which in 2026 falls on the 16th. Counting from September 29 and skipping weekends and those two days, the thirtieth business day is Tuesday, November 10, 2026. From that date, tariff items 8517.13.01, 8517.14.91, 8517.18.99, 8517.62.17 and 8517.69.99 require NOM-221/2, and 8517.18.99 also requires NOM-221 part 1. We recommend confirming the count with your customs broker, because the reading of "30 business days following" can shift the exact effective date by one day.
There is a third date worth keeping in view even though it does not appear in this acuerdo. The NOMs now enforced at the point of entry have been on the books for years: NOM-221-SCFI-2017 since August 2018, NOM-221/2-SCFI-2018 since December 2019, NOM-033-ENER-2019 since July 2021 and NOM-012-CONAGUA-2021 since September 2024. For domestic manufacturers and distributors the obligation was already running, and for cellphones NOM-221 has been enforced at customs since July 1 on the tariff items that were already listed. What September 29 changes is when the authority checks: at customs, before the goods circulate.
The trap: the tariff item triggers, the scope note limits
Almost all 36 new entries carry a scope note that opens with the word "Únicamente," meaning "only." Item 8481.30.01 requires NOM-012 only for check valves for potable water plumbing. Item 8501.10.10 requires NOM-033 only for air-cooled AC motors from 1 W to 37.5 W, 2, 4 and 6 poles, squirrel-cage or electronically commutated. Item 8481.80.99 requires NOM-012 for potable water valves and fittings and expressly excludes steel or bronze pressure relief valves and plastic or rubber toilet tank valves.
That structure creates an asymmetry worth understanding before the first clearance under the new table. Customs sees the tariff item. The tariff item is what activates the requirement. The scope note describes a product, and the only way a check valve for a hydraulic oil circuit classified under 8481.30.01 crosses without a NOM-012 certificate is for the importer to declare on the pedimento that the goods fall outside the scope of the standard, and to have the evidence to back that up if asked during the customs examination. Exclusion is something you prove. Assuming it leaves the shipment exposed.
A case we have seen repeat with every amendment to the NOM annex, with the names changed. An industrial parts importer receives a mixed container every month in which bronze gate valves for potable water share space with gate valves of the same type for process lines carrying fluids other than water, all under 8481.80.04, all from the same supplier, all on the same invoice. Before September 29, that tariff item cleared without a NOM. From the 29th, half the container needs a NOM-012 certificate and the other half needs an exclusion declaration the importer can support with the manufacturer's technical sheet and the declared use. If the invoice describes everything as "2-inch gate valves," the customs broker has two options: hold the shipment until the importer separates the line items, or declare without separating and leave the pedimento with a non-tariff regulation half-proved. In our operation, the right answer is settled the Friday before, with the supplier, in the invoice description.
The consequences of clearing this wrong are in the Ley Aduanera. Article 151, fracción II, authorizes the authority to place a precautionary seizure on goods that fail to prove compliance with the NOMs that apply to them. Article 176, fracción II, defines the infraction of bringing goods into the country without meeting non-tariff regulations and restrictions, and Article 178, fracción IV, sets the fine at 70% to 100% of the commercial value of the goods for NOM non-compliance. For a container of valves or motors, that range turns an invoice description error into a cost on the order of the shipment's value.
A motor importer already selling in the domestic market under NOM-033 reaches September 29 with the certificate on file, the marking on the product and the certification body identified. For that importer, the change is one more line on the pedimento. The importer bringing in the same motors to integrate into equipment that is later exported, who never had to think about NOM-033 because the product was never sold in Mexico, reaches September 29 with the same tariff item and no document. One updates a table. The other finds out at customs that a non-tariff regulation is outstanding, and that obtaining a certificate of conformity is measured in weeks.
What to check before your next clearance
Cross-check your catalog against the 36 new entries before the first shipment arrives, using the same method we laid out in how to read a NOM change without getting burned. Start with your company's classification table: filter the tariff items that appear in the amendment and tag each line with three data points, whether the product falls within the scope note, which NOM applies, and from what date. For faucets and motors the date has passed. For telecom the date is November 10, and thirty business days is enough time to certify a mobile terminal if the process starts this week, and not enough if it starts in November.
Treat exclusion evidence with the same care as the certificate. For every tariff item where your product falls outside the scope note, build the file that supports the exclusion: the manufacturer's technical sheet, the declared use, the fluid or power specification the relevant standard turns on. That file lives next to the pedimento and is produced at the customs examination if requested. Review the commercial description on your supplier's invoice as well, because a generic description is what makes it impossible to separate, at customs, what is subject to a NOM from what is not.
Update the identifier on the pedimento and close the loop with your customs broker. NOM compliance or exclusion is declared on the pedimento through the corresponding identifier in Apéndice 8 of Anexo 22, and the code that has been copied forward on those tariff items for months was correct when it was set. Ask your customs broker to confirm, item by item, which identifier and which complement apply under the table in force since September 29, and to return in writing the list of tariff items in your catalog that are now subject. Across more than 190,000 customs operations a year and more than 39 ports, the failure we have corrected most often after a NOM annex change sits in the importer's catalog that nobody touched.
Talking to a Joffroy expert before your next import cycle lets you review your catalog against the current Anexo 2.4.1 and settle the exclusion evidence before the question arrives during a customs examination.
From September 29, the trade compliance routine has one extra step on 31 tariff items, and from November 10 on five more: before issuing clearance instructions, someone confirms whether the product falls within the scope note of the NOM. That step takes minutes when the catalog is current, and weeks when it is discovered in the bonded yard.
TRADE. UNDER CONTROL.
