At a Glance
The Environment Agency has updated its MCERTS scheme, tightening standards for flowmeters used in regulatory and operational water monitoring in England.
New WMO reporting confirms that global river flows in 2025 were among the lowest in more than 30 years, with continued loss of freshwater storage.
UN and WMO analyses highlight an increasingly erratic global water cycle, with sharper swings between drought and flood.
UN-linked assessments indicate that around 42% of global land area experienced below-normal freshwater reserves in 2025.
Evidence shows water-related disasters and freshwater deficits are increasingly concentrated in Africa and Asia, with severe implications for food security and infrastructure.
This week in water: England’s regulator has tightened the technical standards that underpin how flow in rivers, sewers and networks is measured, aiming to improve the reliability of compliance and operational data. At the same time, a cluster of UN and WMO reports confirms that 2025 was a markedly dry year for the world’s rivers, with widespread declines in glaciers, groundwater and overall freshwater storage. Together these signals point to a system where both the physical resource base and the information used to manage it are under pressure, raising the stakes for accurate monitoring and adaptive planning. Here’s what matters, and why.
Ongoing Stories
There are no explicitly continuing items from previous Weekly Water issues this week; the developments below establish new baselines on regulatory measurement in England and on global freshwater stress that are likely to recur in future coverage.
Key Developments – UK
Environment Agency tightens MCERTS flowmeter standards for regulatory monitoring
The Environment Agency has issued a major update to its MCERTS scheme governing certification of flowmeters used in water flow measurement across England. The revised scheme refreshes and tightens performance standards for equipment used in both regulatory monitoring and operational processes, with a focus on improving accuracy and reliability. The change is designed to strengthen the quality of flow data used for compliance assessments, resource management, and operational decision-making. For utilities, operators and equipment suppliers, this raises the bar on instrumentation specification, procurement, and calibration practices in both water supply and wastewater systems.
(Source: Water Briefing)
Key Developments – Worldwide
2025 recorded among driest years for global river flows, heightening future supply concerns
In a new assessment, the World Meteorological Organization (WMO) reports that river flows worldwide in 2025 were among the lowest seen in more than three decades. The analysis links this to a long-term decline in global freshwater storage, driven by sustained glacier mass loss and increasingly frequent and intense drought conditions. The WMO warns that these trends undermine the security of water supplies for cities, agriculture and industry. For planners and investors, the data reinforces that assumptions on base flows and storage yields require systematic review, with greater weight on drought resilience and diversified sources.
(Source: Reuters)
UN and WMO highlight increasingly erratic global water cycle
Global – The WMO, in UN-linked reporting, warns that the global water cycle is becoming more erratic, with sharper swings between extreme droughts and damaging floods across many regions. Rapid glacier retreat and declining groundwater levels are identified as core drivers of this volatility, increasing risks to water security, agriculture and critical infrastructure. The organisations call for water management systems that can operate under greater variability rather than historical norms. This challenges conventional design return periods and operating rules, implying a need for infrastructure and policy that can handle wider hydrological extremes and faster transitions between them.
(Source: CNN)
UN agencies report freshwater reserves below normal on 42% of global land area in 2025
Global – According to UN agencies, around 42% of the world’s land surface experienced below-normal freshwater reserves in 2025. The assessment attributes this to climate-linked droughts and longer-term water scarcity trends that are affecting ecosystems, agricultural production and human water needs. The breadth of the deficit indicates that reduced storage is no longer confined to traditional arid zones, but is emerging across diverse climatic regions. For national water strategies, this scale of scarcity underlines the need to prioritise demand management, integrated storage (surface and subsurface), and cross-border cooperation on shared basins.
(Source: Le Monde / UN)
Asia and Africa carry greatest burden of water-related disasters and storage deficits
Africa and Asia – New reporting on UN and WMO assessments highlights that roughly 80% of global deaths linked to water resource issues occur in Africa and Asia. Water-related extremes are increasingly threatening food security, infrastructure and livelihoods in regions including the Middle East and North Africa, the Gulf of Guinea, and Eastern Congo, where freshwater reserves show exceptional deficits. The analysis points to a geographic concentration of both hydrological risk and vulnerability, with limited adaptive capacity in many affected countries. For international financiers, utilities active in these regions, and donors, this underscores where resilience investments, risk-sharing mechanisms and basic water security interventions are most urgently needed.
(Source: The New Arab)
WMO consolidates evidence on deteriorating global water trends
Global – The World Meteorological Organization has released a detailed report documenting sustained declines in river flows, groundwater levels and glacier masses across multiple regions. The report links these changes to worsening water availability and increasing unpredictability in timing and volume of water resources. It calls for strengthened water management, improved monitoring and forecasting, and accelerated adaptation to climate-driven shifts in hydrology. As an authoritative synthesis, this provides an evidence base for governments, regulators and infrastructure owners to update design standards, risk registers and long-term investment plans around water security.
(Source: World Meteorological Organization)
Signals to Watch
Regulatory expectations on data quality: the MCERTS update signals continued tightening around measurement standards, with potential knock-on effects for other monitoring domains (e.g. quality, emissions).
Convergence of global assessments: multiple UN and WMO-linked reports are now aligning on the scale of freshwater storage decline, suggesting this will anchor future climate and infrastructure policy debates.
Regional concentration of risk: repeated identification of Africa and Asia as hotspots for water-related mortality and storage deficits indicates where future multilateral funding and regulatory support may increasingly focus.
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