On August 13, 2026, the Decontamination Plan for chlorophyll “A,” transparency and dissolved phosphorus for the Villarrica Lake basin (the “Plan”) was published in the Official Gazette. The Plan will apply to the area declared saturated and seeks to achieve compliance with the lake’s secondary environmental quality standards within a period of 15 years, which may be extended.

The Plan enters into force upon publication, except for those provisions whose application is expressly deferred.

Main Regulatory Impacts

• Fish farming facilities: New and existing facilities located wholly or partially within the saturated area must comply with total phosphorus emission limits, ranging from 80 to 2,100 kg TP/year, depending on their production capacity. For new fish farming facilities, these requirements apply as of publication of the Plan in the Official Gazette, i.e., August 13, 2026. For existing facilities, the applicable compliance periods are 2, 3 or 4 years, depending on annual production capacity. Existing operators must submit a sworn statement and an adjustment plan within three months following publication of the calculation methodology established by the Superintendency of the Environment (“SMA”). Failure to submit these documents constitutes non-compliance with the Plan and may be sanctioned by the SMA.

In addition, operators must report their phosphorus loads and production data on a quarterly basis and monitor nutrients and operational parameters through Environmental Testing and Measurement Entities (“ETFA”), at least three times per month.

• Wastewater treatment plants: New and existing domestic wastewater treatment plants serving 2,500 or more inhabitants must comply with a maximum total phosphorus emission limit, with an average daily concentration of no more than 2 mg/L. For new plants, this requirement applies upon publication of the Plan. For existing plants, the compliance period is 5 years if they do not require an Environmental Qualification Resolution (“RCA”), and 8 years if they do. Additional requirements apply to wastewater treatment plants that use sludge for soil application.
• Projects subject to the Environmental Impact Assessment System (“SEIA”): Projects, activities and modifications that generate an increase over the baseline of 58 kg or more of total phosphorus per year, in any of their phases, must offset 120% of their total annual emissions, whether direct or indirect. The estimate of total phosphorus emissions must be submitted upon entry into the SEIA, and the Emissions Offset Program must be submitted within 60 business days following issuance of the corresponding RCA.
• New housing and residential or tourism developments: Once the buffer zone has been defined, the installation of latrines, cesspools or septic tanks without subsequent treatment will be prohibited within such zone.
• Existing housing and residential or tourism developments: These will have four years from the definition of the buffer zone to implement improvements ensuring at least a 50% reduction in nutrient discharges, or to connect to an authorized system. The buffer zone must be defined by the Regional Ministerial Secretariat of the Environment within one year.
• Forestry, agricultural and/or livestock properties: Registration and reporting obligations are established for properties of 200 hectares or more that apply fertilizers within the saturated area.
• Thermal centers: These facilities must conduct two water monitoring campaigns per year, both at the point of water intake used for their operations and prior to its discharge into surface or groundwater bodies.

Enforcement of the Plan will be carried out by the SMA, without prejudice to the powers of the relevant sectoral authorities.

Recommendation for operators: Operators should review the location of their facilities and projects in relation to the saturated area and the future buffer zone; identify applicable obligations, effective dates, adaptation requirements, and monitoring and reporting duties; and, in the case of projects subject to the SEIA, incorporate the estimation of phosphorus emissions and any related Emissions Offset Program into their regulatory planning at an early stage.

For further information on this matter, please contact: Javier Naranjo (jnaranjo@jdf.cl); Andrea Gallyas (agallyas@jdf.cl); Sofía Ortúzar (msortuzar@jdf.cl); or María Paz Valenzuela (mpvalenzuela@jdf.cl).