Underground storage of hydrocarbons in unlined rock caverns is an established technology which works on the basic principle of hydraulic confinement. Thus, the rock caverns are planned at a depth such that there is sufficient hydrostatic pressure all around to counter the vapor pressure of the stored product. Most of the typical storage unlined caverns have only a horizontal water curtain system in place for confinement of stored product, as these are suitable for saturating vertical to sub-vertical joint sets and features. However, the presence of horizontal joints/features in a given geological domain may require additional saturation of these features using a vertical water curtain system. This paper studies the effectiveness of the vertical water curtain system in the presence of horizontal conductive joints encountered during investigation for hydrogeological confinement. The study deliberates the effect of horizontal conductive joints present at two different locations: joints present 1m below the cavern crown and others in the middle of cavern wall. This study considers both the construction and operational conditions of the cavern. The effectiveness of the water curtain system is discussed in terms of seepage assessment and the minimum hydraulic gradient achieved under varying joint permeabilities and the location of the vertical water curtain borehole arrangement.