Groundwater as integral to climate-resilient WASH

Groundwater’s inter annual storage provides a resilient buffer against climatic extremes, often with lower treatment needs than surface water [2,8]. This, combined with groundwater frequently being the only feasible and affordable option for expanding water access, particularly in rural and underserved areas, makes it both an attractive and climate resilient source of water supply for WASH services [1]. Indeed, groundwater supplied infrastructure, such as handpumps, community standpipes and domestic taps, are common in WASH programmes in LMICs.

Beyond being a water source for WASH services, groundwater is also vulnerable to contamination. Poorly constructed or managed sanitation systems, especially in areas with shallow or unprotected aquifers, can impact groundwater quality, undermining safely managed service delivery and public health [9]. Accounting for groundwater is therefore an already critical, yet undervalued, component in planning and delivery of WASH services.

With increasing climate uncertainty, WASH reliance on groundwater is likely to grow, with groundwater being critical to buffering (but not eliminating) risks to water quality and availability when compared to surface water [9]. Yet, while dependence is increasing, the sustained availability and quality of groundwater is not guaranteed – its sustainability sits at a complex intersection of climate change, evolving water demands and local hydrogeological variability.

The risks and opportunities of using groundwater for WASH services

Understanding groundwater systems is complex, requiring long-term studies, management and planning [2,10,11]. While recent research has raised concerns over rates of global groundwater depletion and its consequences [12,13], including on WASH services, the global picture is not uniform. In some regions, particularly in sub-Saharan Africa, there are untapped groundwater resources that offer opportunities to support climate resilient development [14,15]. In contrast, over-abstraction in India, for example, has led to major challenges with both water quality and quantity [14]. Further, examples from the Bangkok basin and East Salt River basin show that good groundwater management can lead to improvement and recovery from periods of water stress [15]. Groundwater is also strategically valuable for responding to and recovering from climate shocks and humanitarian disasters [5,6].

Determining whether groundwater development presents a risk or an opportunity depends on our ability to understand localised groundwater complexities and their climate feedbacks [2]. To support this determination, groundwater assessments which evaluate storage, recharge, abstraction, and quality are necessary. Conducting these assessments depends on access to groundwater data and the appropriate monitoring systems to capture that data. However, both data and monitoring networks are scarce, especially in LMICs. Financial constraints, technical capacity availability, and fragmented governance frameworks further exacerbate the data scarcity challenge. As a result, in many contexts there is often limited groundwater expertise or knowledge available and where it does exist, it is often under-resourced and overstretched. As such, WASH actors cannot assume effective groundwater management is in place to coordinate with. Instead, if resilience is the goal, WASH actors must be prepared to actively contribute to groundwater characterisation and management needs themselves.

From parallel sectors to integrated thinking

The need for more integrated groundwater-WASH programming is perhaps most acute in sub-Saharan Africa. Persistent failure and low functionality of groundwater supplied WASH infrastructure has long undercut services [16]. In recent years, technology developments, such as solar-powered water pumps, have rapidly expanded across the region, partly driven by Sustainable Development Goal 6 targets, and are commonly implemented as part of standard WASH programmes. However, installation is frequently outpacing the understanding of local groundwater systems and their ability to support the increased demand pressures. Concurrently, climate change and the increasing demand from industrial and agricultural water users, particularly for irrigation, are putting further pressure on groundwater resources [17].

Without groundwater assessments and the mechanisms for collecting monitoring data, there is a dual risk: either exacerbating water stress and undermining climate-resilience or underutilising a strategic resource that could enhance resilience. Similarly, without robust systems and support in place to monitor issues, for example geogenic or anthropogenic water quality contamination, WASH services are, and will remain, at continued risk.

Actions to promote groundwater conscious climate-resilient WASH

We recognise that the challenge of sustainable groundwater management requires attention beyond just WASH. Agricultural withdrawals, for example, typically far exceed those of WASH and the need to coordinate with these sectors is self-evident. However, it is the direct and immediate link between groundwater and resilient WASH services that should compel leadership and investment from within the WASH sector.

As such, groundwater must be recognised as integral to climate-resilient service delivery in WASH programming – and treated as such. The following offers suggested actions which we believe would enhance this recognition:

1. Strengthen support for groundwater assessment and monitoring: Groundwater assessments help identify the risk or opportunity balance for groundwater development. Actively incorporating support for groundwater monitoring and assessment initiatives as part of WASH programmes would make meaningful impact on groundwater data scarcity, especially in LMICs.
2. Align governance and accountability structures: Data-driven monitoring enables more transparent, equitable, and anticipatory resource management strategies [6]. WASH programmes can support this by aligning developments with national water resource strategies, sharing groundwater data from WASH interventions, e.g., submission of drilling reports to regulators, and supporting long-term accountability through compliance monitoring and partnerships with regulators and hydrogeological experts.
3. Embed groundwater in resilience planning and metrics: Where suitable groundwater management is missing, groundwater dependent WASH services cannot be considered climate resilient. Developing metrics that account for groundwater management structures - such as availability of local groundwater assessments or monitoring data - should be used to evaluate the resilience of WASH services.
4. Direct Official Development Assistance and sovereign borrowing finance towards groundwater: Achieving universal access to WASH, enshrined in SDG6, is estimated to require $114 billion USD annually until 2030 [18]. While that amount is a big ask in the current geopolitical climate, it is widely acknowledged that the cost of inaction to society is likely far higher [19]. Investment in groundwater knowledge and management must be seen in the same manner. Redirecting and prioritising some Official Development Assistance and sovereign borrowing to groundwater assessment, monitoring and capacity building could close critical data and knowledge gaps required for ensuring climate resilience. Exploring the role of other finance mechanisms, such as for ecosystem services, should also be explored.
5. Design programmes to maximise co-benefits across sectors: Groundwater management cannot be sidelined into water resource silos. While integrating groundwater into WASH thinking, actors must also work alongside agricultural, industrial and other domestic users to coordinate abstraction, share data, and protect shared aquifers. Integrated management approaches, including with indigenous and local knowledge sources, must be explored and implemented to leverage co-benefits and cohesion across institutions and communities.

Climate change, population and economic change are placing increasing strain on WASH services, making groundwater increasingly critical for resilience. Yet for many regions, particularly in LMICs, groundwater remains poorly understood, inconsistently monitored and weakly governed. Without active integration of groundwater into WASH programming, we risk undermining or overlooking opportunities for building climate-resilience. If WASH is to achieve the aspiration of climate-resilient services, WASH actors must go beyond considering groundwater an interesting side issue. Demonstrating leadership and integrating groundwater into WASH planning, investment, and programming decisions is no longer optional, but essential.