AbstractGrout continuity and the location of the bentonite seal and sand pack in PVC‐cased monitoring wells can be evaluated with cased‐hole geophysical density logs. This method relies upon density contrasts among various completion conditions and annular materials. Notably, the lack of annular material behind pipe (i.e., void space) creates a low‐density zone that is readily detected by borehole density measurements.Acoustic cement bond logging has typically been applied to the evaluation of cement in the annular space of completed oil and gas production wells, and in some cases to ground water monitoring wells. These logs, however, can only be obtained in the fluid‐filled portion of the borehole, and their interpretation is severely hindered by the presence of the micro‐annulus between casing and cement. The influence of the micro‐annulus on cement bond logs can be mitigated in steel‐cased wells by pressurizing the wellbore during acquisition of the log, but this procedure is not feasible in PVC‐cased monitoring wells. The micro‐annulus does not affect cased‐hole density logs or their interpretation.Empirical measurements made in the laboratory with density probes provide information on their depths of investigation and response to specific completion conditions. These empirical data, and general knowledge of the density of annular completion materials (sand, bentonite, cement), are used to support interpretations of cased‐hole density logs acquired in the field. Three field examples demonstrate the applicability of geophysical density logs to the evaluation of PVC‐cased moni