Natural attenuation is considered as an in-situ remediation method. To assess the suitability of the method a model is drawn up based on studies of the soil and groundwater conditions and the specific contaminants in question. The model describes the risk of impact on environment and health and the potential available for natural degradation. The result will be a conclusion as to whether natural degradation of contaminants will be sufficient to avoid risk of impact on the environment and health.

When using in-situ solutions, monitoring programs are established to monitore the progress of contaminant decomposition and to document the sufficiency of the method.