In an urban area, the noise limit comes from a table: the receptor’s zone defines the number and there is nothing more to discuss. In a rural area, it does not. There, the limit is set by your own measurement of rural background noise, and Decreto Supremo N°14/2024 of the Ministerio del Medio Ambiente (MMA, the Ministry of the Environment) changes completely how that measurement is turned into a limit.
From a tailor-made limit to six steps
Until now, each stationary source located in a rural area had its own specific limit, derived directly from the background noise measured at the receptor. The decree itself explains why this was changed: to reduce the dispersion of limits and give greater certainty about which number has to be met, the possibilities were narrowed down to discrete ranges, as in urban areas.
The result is tables N°6 and N°7 of the decree. For the daytime period, six steps:
| Rural background noise level (dBA) | Daytime limit (dBA) |
|---|---|
| ≤ 32 | 40 |
| 33 to 37 | 45 |
| 38 to 42 | 50 |
| 43 to 47 | 55 |
| 48 to 52 | 60 |
| ≥ 53 | 65 |
At night there are only three, and the limit is capped at 50 dBA however high the background noise is:
| Rural background noise level (dBA) | Night-time limit (dBA) |
|---|---|
| ≤ 32 | 40 |
| 33 to 37 | 45 |
| ≥ 38 | 50 |
In the SEIA, the background noise level gets written down
Article 13 of the decree establishes that, for projects or activities submitted to the Sistema de Evaluación de Impacto Ambiental (SEIA, the Environmental Impact Assessment System), at receptors located in rural areas the rural background noise level will be the one established in the assessment process or in its respective Resolución de Calificación Ambiental (RCA, the environmental approval).
In other words: the value that is measured and declared during the permitting process is the one that defines the project’s limit from then on, without prejudice to the measures that may be required under article 25 quinquies of Law N°19.300. The baseline stops being background information and becomes part of the commitment.
How that level is measured
Article 12 sets out the procedure: the rural background noise level is obtained using the NPSeq descriptor in dBA, measuring until it stabilises, with a minimum of 15 minutes and no more than 30. The decree states explicitly that this minimum time is extended compared with the previous standard, in order to reduce the variability of the levels recorded in rural areas.
Under D.S. N°38/11 of the MMA, that minimum was 10 minutes. It is worth noting that the new decree did not lengthen every measurement time: the residual noise level in article 19 keeps its 10-minute minimum. What was extended was the one for rural background noise, precisely the one that defines a limit.
A case worth keeping in mind
Article 14 resolves a common situation in rural projects: when the receptor is a person who lives, resides or stays in a workplace associated with productive activities located in a rural area, authorised under the fourth paragraph of article 55 of the Ley General de Urbanismo y Construcciones (General Law on Urban Planning and Construction), the limits of Zone IV apply: 70 dBA by day and 70 dBA at night.
Since when
The decree enters into force 30 months after its publication on 27 February 2026, that is, on 27 August 2028. But for projects entering the SEIA from that publication date, the period is 18 months: 27 August 2027. Until then, D.S. N°38/11 of the MMA continues to apply, and it is repealed when the new decree comes into force.
For a project that is defining its baseline now, this means that the background noise campaign carried out this year may be fixing the limit it will have to meet under the new standard.
If your project is heading into the SEIA with receptors in rural areas and you are defining its noise baseline, see our acoustic and vibration impact studies for the SEIA. Would you rather talk it through? Book a 20-minute call: we will carry out a free preliminary diagnosis and send you a free technical proposal within 1 to 5 working days.
He leads Acústica Austral’s environmental noise and vibration studies for the SEIA across energy, port and infrastructure projects, and has contributed to reference work for Chile’s Ministry of the Environment.
Meet the team →Free resources for your project
Guide to the D.S. N°14/2024 and the acoustic checklist for entering the SEIA, in PDF. We email them to you.