Rainwater harvesting (RWH) is a critical technique for enhancing sustainable water management. Unreliable rainfall patterns are among the leading causes of water shortages in drought-prone regions like Balochistan, where rainfall runoff accounts for only a small share. Hence, rainwater harvesting is a proper way to reduce surface runoff and increase groundwater resources. This study emphasizes identifying suitable rainwater harvesting zones in the Quetta Division using the multi-influence factor (MIF), fuzzy overlay, and weighted linear combination (WLC) techniques in the GIS domain. A total of 9 RWH influencing parameters were used in the zone suitability analysis via an overlay process: lithology, rainfall, slope, soil type, land use, land cover, elevation, distance from the road, lineament, and drainage density. The results classified the study area into four RWH suitable zones: very low, low, moderate, and high. The MIF model covers a very low area of 4,804 km2, a low area of 4,222 km2, a moderately sized area of 3,494 km2, and a high area covering 2,038 km2. Fuzzy overlay produced a very low RWH suitable zone with an area of 3,931 km2, a low zone of 2,621 km2, a moderate zone of 4,804 km2, and a high zone covering 3,203 km2. Moreover, through WLC, an area of approximately 3,494 km2 is covered by a very low suitable zone, 3,931 km2 by a low suitable zone, 4,659 km2 by a moderate suitable zone, and 2,475 km2 by a high suitable zone. The results were validated with the existing RWH structures. The findings are helpful to relevant agencies and decision-makers in designing RWH structures in the study area to address water scarcity.