Reviewed 4 November 2026.
Environmental due diligence on Mexican real estate establishes five facts about a site: whether its works needed an environmental impact authorization and comply with it, whether the Procuraduría Federal de Protección al Ambiente (PROFEPA, the federal environmental enforcement agency) has inspected or sanctioned it, whether its soil is contaminated, whether its water is held under a valid title, and whether the zoning allows the intended use. The answers sit with the Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT, the Environment Ministry) or a state agency, with PROFEPA, with the Comisión Nacional del Agua (CONAGUA, the National Water Commission) and with the municipality.
Three rules make these the buyer's problem as well as the seller's. Owners and possessors of private land with contaminated soil are jointly liable for its remediation, and land contaminated with hazardous waste cannot be transferred without SEMARNAT's express authorization. Since December 2025, rights under a water concession cannot be transferred by contract. This is the environmental strand of due diligence in Mexico, for buyers, lenders and investors in land, industrial sites and resort property.
US buyers and lenders usually commission a Phase I environmental site assessment from an environmental engineer. That is a US standard. The Mexican answers sit in authority files, gazettes and registries, and on the ground.
The law as of November 2026
The Ley General del Equilibrio Ecológico y la Protección al Ambiente (LGEEPA, the General Law of Ecological Balance and Environmental Protection) carries a last reform of 19 January 2026 in its consolidated text. That decree, issuing a new Ley General de Economía Circular (General Circular Economy Law), left the impact authorization article and the waste law's contaminated-site articles unchanged. On 11 December 2025 the Diario Oficial de la Federación (DOF, the Federal Official Gazette) published a decree issuing a new Ley General de Aguas (General Water Law) and rewriting much of the Ley de Aguas Nacionales (LAN, the National Waters Law).
The environmental impact authorization: federal or state
Article 28 of the LGEEPA defines environmental impact assessment as the procedure by which SEMARNAT sets the conditions for works and activities that may cause ecological imbalance, and requires SEMARNAT's prior authorization for the works it lists, in the cases the regulation sets. The promoter applies by filing a manifestación de impacto ambiental (MIA, the environmental impact statement) describing the possible effects on ecosystems and the measures to prevent and mitigate them (Article 30).
The list includes pipelines and hydraulic works, the oil, chemical, steel, cement and electricity industries among others, mining, hazardous waste facilities, changes of land use in forest areas, jungles and arid zones, industrial parks with highly risky activities, real estate developments that affect coastal ecosystems, works in wetlands, coastal ecosystems and lagoons connected with the sea, and works in federal protected natural areas (fractions I to XI).
Article 5 of the impact regulation, last amended on 31 October 2014, gives the detail. Its coastal section covers hotels, condominiums, housing developments, golf courses and marinas that affect coastal ecosystems. A plant in an authorized industrial park may file a shorter informe preventivo (preliminary report) instead of an MIA (Article 31 of the LGEEPA). Hydrocarbons sector works, including retail sale of fuels, are listed separately, and the Agencia Nacional de Seguridad Industrial y de Protección al Medio Ambiente del Sector Hidrocarburos (ASEA, the hydrocarbons safety and environment agency) inspects them in place of PROFEPA (Articles 5 and 55 of the regulation).
The states evaluate the environmental impact of works not expressly reserved to the federation (Article 7, fraction XVI), with municipalities taking part for works in their territory (Article 8, fraction XIV). An inland housing development or a warehouse is usually authorized by the state environment agency under state law, and the search starts there.
What the authorization contains
SEMARNAT must resolve within 60 days, extendable once by up to 60 more for large or complex projects (Article 46 of the regulation). It may authorize the project as filed, authorize it in whole or in part subject to conditions, or refuse it (Article 45). Conditions can apply before works start and through construction, operation and abandonment (Article 48). Where works could seriously damage ecosystems, SEMARNAT may require insurance or a guarantee of compliance (Article 51).
The authorization covers only the environmental aspects of the project, and its term cannot exceed the time proposed for carrying it out (Article 49). The buyer reads every condition, checks that the term has not run out and compares what stands on the site with what was authorized. A change to the project, its deadlines or its terms goes through SEMARNAT's modification procedure (SEMARNAT-04-008).
Whether the authorization passes to a buyer
The authorization is granted for a specific project, and the works must be carried out as the resolution provides (Article 47 of the regulation). The promoter must notify SEMARNAT of the start and completion of the project and of any change in its holder (Article 49). SEMARNAT handles the change as an application for a change of holder (SEMARNAT-04-009), which an agreement signed on 2 September 2026 moves to its Ventanilla Electrónica Ambiental (Environmental Electronic Window) once that agreement takes effect.
In an asset purchase, the buyer should make SEMARNAT's approval of the change of holder a condition to closing, so that the authorization, its conditions and any guarantee stand in its own name. In a share purchase the company keeps the authorization, with its conditions and any breach of them. Either way, a condition the seller never met becomes the buyer's to cure.
Reading SEMARNAT's files from outside
Once SEMARNAT receives an MIA and assembles the file, it must make the statement available for anyone to consult (Article 34 of the LGEEPA). Article 38 of the regulation opens evaluation files to any person, except information the promoter identifies as protected industrial property or confidential commercial data. Article 37 requires SEMARNAT to publish weekly in the Gaceta Ecológica (Ecological Gazette) a list of the applications and MIAs it receives, with the promoter, filing date, project name, type of study and state and municipality, and to post it electronically.
The gazette also lists resolutions issued, with the project key, the resolution date and the term granted. A search therefore runs by promoter name and municipality, covering the owner, the developer and earlier holders of the land, and leads to the file and the resolution with its conditions. A project that needed an authorization and has no filing on record is a finding in itself. Any member of the affected community may ask for a public consultation on an MIA (Article 40), and one on file points to local opposition.
PROFEPA: inspections, closures and fines
Under Article 55 of the impact regulation, SEMARNAT inspects compliance through PROFEPA, or through ASEA for the hydrocarbons sector, and imposes the security measures and sanctions that apply.
Where there is an imminent risk of ecological imbalance or serious damage to natural resources, or contamination dangerous to ecosystems or public health, PROFEPA may order the security measures listed in Article 170 of the LGEEPA, among them the temporary, partial or total closure of the polluting sources and the precautionary seizure of hazardous materials and waste (Article 56 of the regulation). Where works that needed an impact authorization go ahead without one, it orders corrective or urgent measures, without prejudice to sanctions and civil and criminal actions, and sends the works not yet started through impact assessment (Article 57). Breach of an authorization's conditions also triggers security measures (Article 59). PROFEPA announces closures of developments and plants, and the local press reports them.
Corrective measures are the restoration orders. In order of priority, they aim to stop further harm, to restore the natural resources affected, or to produce an alternative positive effect equivalent to the harm (Article 58). The inspected party must report compliance with each measure within five days after its deadline (Article 61), which leaves a paper trail.
Fines under Article 171 of the LGEEPA run from 30 to 50,000 days of the general minimum wage, a reference read since the 2016 constitutional reform as the Unidad de Medida y Actualización (UMA, the indexed unit for legal amounts). At the 2026 daily UMA of MXN 117.31 the maximum is about MXN 5.9 million. A repeat offense can draw up to three times the original fine and definitive closure. Liability for environmental damage under the Ley Federal de Responsabilidad Ambiental (Federal Environmental Liability Law), which runs for twelve years, is covered in our article on legal due diligence in Mexico.
Finding out about open proceedings
The impact regulation requires SEMARNAT to publish impact filings every week. It sets no equivalent publication for inspection proceedings, so the seller is the first source. The buyer asks for every inspection order, acta de inspección (inspection record), resolution and compliance notice, and searches PROFEPA's announcements and the press by location and by every company name involved.
Fines and resolutions ending an administrative proceeding can be challenged before the Tribunal Federal de Justicia Administrativa (TFJA, the Federal Court of Administrative Justice) under Article 3 of its organic law, so a litigation search on the seller and the operator covers that court and the amparo (constitutional relief) courts.
Contaminated land
The Ley General para la Prevención y Gestión Integral de los Residuos (LGPGIR, the General Law for the Prevention and Integrated Management of Waste), in its consolidated text, places remediation on two groups. Whoever generated or handled the hazardous materials or waste that contaminated a site must remediate it (Article 69). Owners and possessors of private land, and holders of concessions, whose soil is contaminated are jointly liable for the remediation needed, with a right of recourse against the polluter (Article 70). A buyer who acquires contaminated land therefore acquires the liability, whatever the seller's indemnity says.
Article 71 adds two rules for the sale. Ownership of a site contaminated with hazardous waste cannot be transferred without SEMARNAT's express authorization. Anyone who transfers property contaminated with hazardous materials or waste because of the activities carried out there must inform the acquirer. The seller's answer belongs in a written representation, and contamination found before signing makes the sale itself subject to SEMARNAT's authorization.
The Mexican soil standards
Contamination is measured against normas oficiales mexicanas (NOMs, the Mexican official standards). NOM-138-SEMARNAT/SSA1-2012 sets maximum permissible limits for hydrocarbons in soil, with sampling and remediation specifications. It was published on 10 September 2013, and the Catálogo Mexicano de Normas (the government catalog of standards) lists it as in force, confirmed by a review of 10 August 2023. NOM-147-SEMARNAT/SSA1-2004, published on 2 March 2007 and also in force, sets remediation criteria for soil contaminated with arsenic, barium, beryllium, cadmium, hexavalent chromium, mercury, nickel, silver, lead, selenium, thallium or vanadium.
Both standards tie the limit to land use. NOM-138 sets separate limits for agricultural, forestry, livestock and conservation land, for residential and recreational land, and for industrial and commercial land, and applies the strictest where uses are mixed. NOM-147 separates industrial use from other uses and applies the residential value where the ecological and urban development programs set no use. A buyer converting an industrial site to housing or a resort should therefore have the engineer test against the intended use.
Water: titles, the registry and the 2025 reform
National waters are used under a concesión (concession), a title the federal executive grants through CONAGUA or the relevant river basin agency (Article 3, fraction XIII, of the LAN). Titles, assignments and discharge permits, and changes to them, are recorded in what the reform now calls the Registro Público Nacional del Agua (REPNA, the National Public Water Registry), formerly the Registro Público de Derechos de Agua (REPDA) (Article 3, fraction XLIV). CONAGUA describes the registry as open to public consultation.
Under Article 22 as reformed by the December 2025 decree, rights under concessions and assignments cannot be transferred. Preferential rights arising from a transfer of property, a merger or split of companies, or succession are reassigned under a new Article 37 Bis 1, through an expedited procedure the water authority must resolve within 20 business days. It issues a new title to the person who proves the property, representation or succession rights, with the same volume and use and the remaining term of the old title.
A buyer of a farm, a plant or a resort with wells therefore does not take the seller's water title with the deed. It needs the water authority to reassign the volume and issue a title in its own name, which the purchase agreement should make a condition to closing. The buyer checks each title in the registry against the wells and discharge points found on the site.
Land use and ecological zoning
Uso de suelo (land use) is a local matter. Municipalities formulate, approve and administer the zoning of population centers and issue the permits for urban development works, in strict line with local plans (Article 11, fractions III and XI, of the Ley General de Asentamientos Humanos, Ordenamiento Territorial y Desarrollo Urbano, the General Law of Human Settlements, Land Planning and Urban Development). The notary obtains the land use certificate for the deed, as our guide to checking property title in Mexico explains, but the certificate states what the plans allow, not what happens on the land.
Mexico City's single zoning certificate
In Mexico City the document is the Certificado Único de Zonificación de Uso del Suelo (single zoning and land use certificate), issued by the Secretaría de Desarrollo Urbano y Vivienda (SEDUVI, the city's Urban Development and Housing Ministry). The regulation of the city's urban development law defines it as a public document stating the specific rules that the planning instruments set for a lot, and says it creates no property or possession rights and is not a permit or license (Article 4, fraction IX). It states the zoning, the maximum construction area and the permitted uses, and forms part of the deed of transfer executed before a notary (Article 21).
A use that predates the program that prohibited it is recognized through a separate Certificado de Acreditación de Uso del Suelo por Derechos Adquiridos (certificate of acquired land use rights), which states the use and surface accredited (Article 4, fraction XI, and Article 21). A buyer of a plant or a hotel in the city checks that the use it will operate appears in one of the two certificates.
Ecological zoning and protected areas
Outside cities, programas de ordenamiento ecológico (ecological zoning programs) also govern land use. The LGEEPA provides for general, regional, local and marine programs (Article 19 Bis). Local programs are issued by municipal authorities and regulate land uses outside the limits of population centers (Articles 20 Bis 4 and 20 Bis 5). SEMARNAT must follow these programs, the urban development programs and the declarations of protected natural areas when it evaluates an MIA (Article 35), so a project the local program does not allow is exposed to refusal.
Federal áreas naturales protegidas (protected natural areas) are administered by the Comisión Nacional de Áreas Naturales Protegidas (CONANP, the National Commission of Protected Natural Areas). Works inside one need SEMARNAT's impact authorization (Article 28, fraction XI), and the buyer checks the site's boundaries against the area's declaration. Beachfront land also borders the zona federal marítimo terrestre (ZOFEMAT, the federal maritime land zone), federal property used under concession, as our article on buying beachfront property in Mexico explains. Where a foreign buyer will hold coastal land through a bank trust, our article on the fideicomiso in Mexico covers that structure.
The Phase I: a US standard
ASTM E1527-21, the standard for the Phase I environmental site assessment, describes itself as good commercial and customary practice in the United States for assessing commercial real estate for contamination. It is meant to help a buyer qualify for the landowner liability protections of CERCLA, the US federal statute on hazardous substance cleanup, and the US Environmental Protection Agency treats it as consistent with its all appropriate inquiries rule at 40 CFR Part 312.
Mexican law does not require a Phase I for a sale, and a Phase I does not answer the Mexican questions in this guide. US buyers and lenders commission one from environmental engineers all the same. The engineer inspects the site and, where the findings justify it, samples soil against the Mexican standards. The records and the field work tell the engineer where to look, and the sampling shows what the records cannot.
What the records leave out
Records do not show activities that were never declared, wells or discharge points outside the water titles, waste stored on the site, or what adjoining operations discharge. A field visit establishes what is visibly operating on and around the site and sets it against the authorizations, titles and certificates on file. It closes the gap described in our note on why a foreign due diligence checklist falls short in Mexico.
Disputes with neighbors, communities or ejidos (agrarian communities) are found through litigation searches, the local press and inquiries near the site. The record of the seller and the operator at other sites, and who stands behind them, are checked as described in our guide on how to verify a Mexican company.
Where we come in
Warden Consulting carries out the record and field work behind environmental due diligence in Mexico from its office in the World Trade Center in Mexico City, with investigating lawyers working the federal and state files and investigators in the states where the sites are. On the record side that means locating MIA filings and resolutions, PROFEPA proceedings and their press coverage, the permits and land use certificates on file, community, neighbor and agrarian disputes and litigation, and background on the seller and the operator. In the field it means a check of what is visibly operating on and around the site.
We do not do environmental engineering or sampling, which stay with the buyer's environmental engineer together with the Phase I. We report the records against the field findings and mark where they disagree, so that the deal team, its counsel and its engineer know what to test before signing. To scope a review, contact our Mexico City office.
Frequently asked questions
Do I need an environmental impact assessment to build in Mexico?
It depends on the works. Article 28 of the LGEEPA requires SEMARNAT's prior authorization for the works it lists, among them coastal real estate developments, works in wetlands and federal protected areas, and certain industries. Other works are evaluated by the state (Article 7, fraction XVI).
Does an environmental impact authorization transfer when you buy property in Mexico?
Not on its own. The holder must notify SEMARNAT of a change in holder (Article 49 of the impact regulation), which SEMARNAT handles as an application (SEMARNAT-04-009). In an asset purchase, make its approval a condition to closing. In a share purchase the company keeps the authorization and its conditions.
Who is liable for contaminated land in Mexico?
Whoever caused the contamination must remediate it, and owners and possessors of contaminated private land are jointly liable for remediation, with recourse against the polluter (Articles 69 and 70 of the LGPGIR). Land contaminated with hazardous waste cannot be transferred without SEMARNAT's express authorization (Article 71).
What is uso de suelo in Mexico?
It is the land use that local zoning allows on a lot. Municipalities set the zoning and issue land use and construction permits under local plans. In Mexico City the document is the Certificado Único de Zonificación de Uso del Suelo, which states the zoning, permitted uses and maximum construction for a lot and forms part of the deed.
Can water rights be transferred with land in Mexico?
Not by contract since the December 2025 reform. Article 22 of the LAN now provides that rights under concessions cannot be transferred, and preferential rights arising from a transfer of property are reassigned under Article 37 Bis 1, with a new title issued in the buyer's name.
Is a Phase I environmental site assessment required in Mexico?
No. ASTM E1527-21 is a US standard built around US federal liability protections. US buyers and lenders commission one for Mexican sites anyway, alongside searches of Mexican records and a field check.
This article is general information, not legal advice.