Regional water systems face growing pressure from climate variability, water scarcity, and increasingly complex wastewater pollution. These challenges require governance models that integrate institutional coordination with effective technological solutions. This review is based on a structured analysis of peer-reviewed literature indexed in Scopus, Web of Science, and ScienceDirect, covering publications from approximately 2014 to 2025. The findings show that clearly defined institutional roles, basin-level coordination, stable financing mechanisms, and active stakeholder participation significantly improve governance outcomes. Technological advances such as membrane filtration, advanced oxidation processes, nature-based treatment systems, and digital monitoring platforms enhance treatment efficiency, resilience, and opportunities for resource recovery. Regions differ widely in their ability to adopt these solutions, mainly due to variations in governance coherence, investment capacity, and climate-adaptation readiness. The review highlights the need for policy frameworks that align institutional reforms with technological modernization, including the adoption of basin-based planning, digital decision-support systems, and circular water-economy principles. These measures provide actionable guidance for policymakers and regional authorities seeking to strengthen long-term water security and wastewater management performance.

Sustainable water resource management in arid and transboundary-dependent regions requires that hydrological assessment be integrated with institutional governance analysis. This study provides a comprehensive hydro-institutional evaluation of water sustainability in Kazakhstan using a multi-source empirical framework. The analysis is based on international and national datasets (FAO AQUASTAT, World Bank, national statistics for 2010–2024) and incorporates key indicators, including per capita renewable water resources, sectoral withdrawal structure, transboundary dependence, and water stress. In addition, a Water Sustainability Composite Index and a Regional Vulnerability Index were developed to capture system-wide sustainability and spatial heterogeneity. The results show that Kazakhstan possesses moderate renewable water availability (approximately 5411 m³ per capita per year), yet exhibits significant structural vulnerability due to high transboundary dependence (40.64%), dominant agricultural water use (≈57%), and infrastructure inefficiencies (25–35% losses). Regional analysis reveals substantial disparities, with southern irrigation-dependent regions demonstrating higher vulnerability compared to resource-abundant eastern basins. Elasticity analysis indicates that improvements in irrigation efficiency have a substantially greater impact on sustainability than equivalent changes in transboundary inflows, highlighting the dominant role of internal system performance. The findings suggest that water sustainability in Kazakhstan is primarily constrained by governance effectiveness and efficiency limitations rather than absolute resource scarcity. This study contributes to the literature by integrating quantitative hydrological indicators with institutional analysis through a composite modeling framework, demonstrating that internal system efficiency—particularly irrigation performance—has a significantly greater influence on sustainability outcomes than external hydrological variability. The proposed approach provides a transferable methodology for assessing water sustainability in semi-arid and transboundary contexts.