• Key reservoirs down to weeks of supply, forcing strict rationing
• Pollution and salinity risks threaten core treatment operations
• Nearly 50% of water lost before reaching consumers
• Demand outstrips capacity by up to 300%
• New projects delayed, with relief unlikely before 2028

Colombo is grappling with a deepening drinking water crisis, as an intense dry spell and rapidly declining reservoir levels strain supply across the district. 

The National Water Supply and Drainage Board (NWSDB) has imposed a series of scheduled water cuts and pressure reductions in a bid to manage dwindling stocks, with disruptions now affecting both suburban and urban areas.

Crisis and water cuts

Under the current schedule for April, the most severe restrictions are being felt in areas supplied by the Labugama and Kalatuwawa reservoirs, where water levels have fallen sharply. 

Homagama and Pelenwatta were subjected to a 12-hour water cut from 8 p.m on Thursday (9) until 8 a.m on Friday (10), while areas such as Padukka, Hanwella, Maharagama, and Pannipitiya are experiencing extended disruptions ranging from 18–24 hours on a rotational basis, typically followed by several days of continuous supply.

In parts of Battaramulla, Pamankada, Wellawatte, and Nawala, nightly three-hour cuts from 10 p.m to 1 a.m are being enforced every other day to maintain system pressure. 

The crisis is being driven by a combination of factors. Reservoir levels have reached critical lows, with Kalatuwawa reportedly holding only around 20 days of supply as of early April, while Labugama has approximately 50 days remaining. 

At the same time, reduced water levels in the Kelani River have heightened the risk of salinity intrusion, raising concerns over the operational stability of the Ambatale Water Treatment Plant, which supplies a significant portion of Colombo’s drinking water.

Demand has also surged amid prevailing hot weather conditions and the approach of the Sinhala and Tamil New Year, placing further pressure on an already strained system. 

Beyond the immediate shortages, officials and experts warn that the crisis reflects a deeper structural issue driven by years of underinvestment in water infrastructure. A prolonged stagnation in capacity expansion and delayed development projects has widened the gap between supply and rising urban demand, particularly in Colombo’s rapidly expanding residential and commercial zones. 

They also note that while short-term measures such as rotational cuts and pressure management provide temporary relief, the city urgently requires sustained long-term solutions, including new treatment capacity, network upgrades, and integrated water management strategies, to ensure future water security.

Looking ahead, concerns remain over the duration of the crisis. The Department of Meteorology has warned that El Niño conditions may persist, potentially prolonging dry conditions until September 2026. Although some relief is anticipated with the onset of the southwest monsoon around 20 May, authorities have urged residents to adopt strict water conservation measures in the interim.

A century-old network

While the current drought has brought Colombo’s water scarcity to the forefront, a primary contributor to the city’s water insecurity is its ageing distribution system. 

Significant portions of the pipeline network within the Colombo Municipal Council (CMC) limits date back over 100 years to the British colonial period. These cast-iron pipes are highly susceptible to corrosion and frequent bursts, leading to a massive loss of treated water. 

According to the National Water Supply and Drainage Board (NWSDB) and the Asian Development Bank (ADB), Colombo has historically faced a Non-Revenue Water (NRW) rate water that is produced but lost before it reaches the customer, of approximately 45% to 50%. 

This means nearly half of the city’s treated water is wasted through leaks or illegal connections. While ongoing rehabilitation projects, such as the Greater Colombo Water and Wastewater Management Improvement Investment Program, aim to reduce this rate to 18%, the complexity of excavating a modern, dense city continues to slow progress. 

The Ambatale Water Treatment Plant, which provides roughly 50% of the water for the Western Province, faces an annual threat from salinity intrusion. As river levels drop during dry spells, the salt wedge from the Indian Ocean pushes upstream. 

As of 8 April, the Irrigation Department confirmed that the permanent salinity barrier intended to protect the Ambatale intake was still under redesign. Currently, authorities rely on a semi-permanent structure reinforced with sandbags. Experts warn that a permanent, gated barrier is at least two years away from completion, leaving the city’s primary water source vulnerable to seawater contamination every dry season. 

The rapid expansion of high-rise developments has outpaced the capacity of existing water mains, leading to low pressure even when reservoirs are full. Furthermore, a chronic lack of vision regarding rainwater harvesting has been cited as a missed opportunity to build national resilience. 

Despite an annual rainfall average of 2,000 mm, Colombo remains almost entirely dependent on surface water from the Kelani River and the Labugama and Kalatuwawa reservoirs.

Immediate and long-standing weaknesses

Experts and officials responding to The Sunday Morning pointed out that Sri Lanka’s ongoing water stress reflects both immediate climatic pressures and long-standing structural weaknesses, while highlighting rainwater harvesting as a critical yet underutilised solution. 

NWSDB Chairman Chandana Bandara attributed the current water shortages to a combination of climatic and demand-side pressures. “The crisis is driven by a double blow of extreme heat and a prolonged dry period following the last cyclone, which has significantly increased public demand,” he said. 

He explained that water levels in key reservoirs such as Labugama and Kalatuwawa have dropped sharply, forcing the NWSDB to reduce production. This has primarily affected high-elevation areas, including Hanwella, Padukka, Homagama, Kottawa, Godagama, Meegoda, Piliyandala, Kesbewa, and Pannipitiya. 

“To manage the situation, we introduced a 12-hour rotational supply system across five zones, diverting water from higher catchments to densely populated areas such as Maharagama and Piliyandala,” Bandara said. 

He noted that temporary relief would be provided during the Sinhala and Tamil New Year period. “Restrictions will be lifted from 11 to 14 April, with production increased temporarily. We will reassess the situation on 15 April based on rainfall patterns,” he said. 

Colombo city has remained largely unaffected due to its reliance on the Kelani River via the Ambatale treatment plant, which continues to maintain sufficient water levels. 

Bandara identified a five-year stagnation in infrastructure development as a key structural issue behind the widening gap between supply and demand. “Between 2019 and 2024, due to the Easter attacks, COVID-19, and the economic crisis, not a single cubic metre of new production capacity was added,” he said, noting that demand simultaneously surged due to urbanisation, industrial expansion, and migration into Colombo. 

He said the NWSDB was now pursuing multiple long-term projects to address this deficit. These include a new 500,000 cubic metre per day treatment plant at Ambatale, expected to go to tender in May 2026; the Kalu Ganga Phase 2 project, which will add 72,000 cubic metres; and a planned 180,000 cubic metre facility in Hanwella. 

“However, these projects typically take between two-and-a-half to three years to complete, meaning the additional capacity will only be integrated into the system by late 2028 or 2029,” he said. 

In the interim, the NWSDB is focusing on reducing wastage and improving efficiency. Bandara said leakage in Colombo has already been reduced from 15% to 2%, with a further $ 35 million project planned for Kolonnawa. He added that ageing infrastructure remained a significant challenge. “We are replacing 60- to 70-year-old cast-iron pipelines in areas like Kotte and Colombo, which have lost carrying capacity over time,” he said. 

Looking ahead, he emphasised the need for stronger policy coordination. The Government is currently developing a Water Share Policy to better allocate resources between irrigation, agriculture, and drinking water. “Improving communication between agencies such as the NWSDB, Community Water Supply, and the Irrigation Department is essential,” he said.

Bandara also acknowledged the growing importance of rainwater harvesting. “While it is widely practised in rural areas, it has not yet been effectively implemented in urban centres like Colombo, where most rainwater is wasted and discharged into canals, lakes, or the sea,” he said. 

He added that integrating urban rainwater harvesting into national planning would be crucial. “We recognise it as a necessary component of future water security and intend to work with ongoing Ministry-level initiatives to expand its implementation,” he said.

The issue of resource management

Dr. Nadeesha Chandrasena, an urban innovator and environmental specialist, said experts had highlighted deeper structural and planning challenges underpinning Colombo’s recurring water crises, pointing to both demand-side pressures and infrastructure limitations. 

Dr. Chandrasena, speaking from a city planning and resource management perspective, noted that Sri Lanka’s water supply operated within a subsidised social welfare framework. “While it may cost around Rs. 100 to produce a unit of water, it is provided to the public at approximately Rs. 45,” she said, adding that international agencies such as the World Bank had explored reforms to such incentive structures. 

She identified Colombo’s massive floating population as a key driver of demand. “The city’s infrastructure may be designed for a carrying capacity of around 500,000 people, but an additional 1.5 million enter the city daily for work and services. This means actual demand exceeds the designed capacity by 100% to 300%,” she explained. 

Dr. Chandrasena said that addressing water shortages required a shift beyond reliance on the Kelani River. “We must look beyond the Kelani River, which remains our only major source, and identify alternative water sources. At the same time, we need to adopt low-cost technologies to convert available water into potable standards, as current purification processes are extremely costly for a country like ours,” she said.

From a planning standpoint, she emphasised the need to manage demand by reducing pressure on Colombo, noting that while solutions such as desalination are used in regions like the Middle East, they remain high-cost options requiring further research before being considered locally.

“The water issue in Colombo is primarily a resource planning issue rather than a city planning issue. While city planning addresses how a city functions and interacts, the fundamental challenge here is the availability and management of the water supply itself. No matter how effectively a city is planned, you cannot bridge this massive gap without identifying alternative water sources. 

“We have relied on the Kelani River since ancient times, and it remains our only major source. To address this, we must prioritise resource planning by researching and identifying new sources and adopting low-cost technologies to convert available water into potable standards. While city planning can help mitigate demand, for instance, by decentralising administrative services or introducing work-from-home models to reduce the floating population, the core of the problem remains a lack of diverse water resources,” she pointed out.

Meanwhile, Supun Meegahakumbura, a PhD candidate currently pursuing studies in Australia, speaking from an infrastructure and quality control perspective within the water sector, said efforts were underway to modernise the country’s ageing distribution network. “While many areas still rely on old cast-iron or ductile iron pipes, new projects are shifting towards High-Density Polyethylene (HDPE) pipes,” he said.

He identified Non-Revenue Water (NRW) as a major technical challenge. “This refers to water that is produced but lost before reaching the consumer, mainly due to leaks in the ageing pipe network and, to a lesser extent, illegal connections. We have established dedicated leak detection programmes and allocated budgets to address these losses,” he said.

Meegahakumbura also raised concerns over the quality of Colombo’s primary water source. “The Kelani River is heavily polluted. Microbial contamination, particularly E. coli, can reach levels of 300,000–500,000 units, compared to an acceptable level of fewer than 5,000 for a raw water source,” he said, noting that this significantly increases treatment costs.

Despite this, he emphasised that treated water supplied to consumers met strict national standards. “We adhere to the Sri Lanka Standards Institution (SLSI 614:2013) requirements, ensuring that E. coli levels are reduced to zero before distribution,” he said. 

Looking at alternatives, Meegahakumbura noted that while groundwater was successfully utilised in parts of the Northern Province, Colombo had limited potential for such sources. “We are also exploring low-cost options such as rainwater harvesting for non-potable uses like gardening and irrigation, though achieving drinking water standards through these methods remains a challenge for future research,” he added.

Rainwater harvesting

Lanka Rainwater Harvesting Forum Executive Director Thanuja Ariyananda stressed that urban households, particularly in Colombo, had to fundamentally shift their approach to water usage by incorporating rainwater harvesting systems capable of meeting at least 30% of daily water needs. 

“This water is perfectly suitable for gardening, flushing toilets, doing laundry, washing houses, and even bathing,” she said, highlighting its versatility for non-potable domestic use. 

She noted that such systems could deliver both household- and national-level economic benefits. “Households can reduce their water bills by between 30% and 60%, depending on usage levels,” she said, explaining that lower consumption could shift users into subsidised tariff brackets.

Ariyananda added that reduced individual demand would allow the NWSDB to redistribute treated water more efficiently. “The Government currently subsidises water for those using under 25 units, so promoting rainwater harvesting reduces this financial burden,” she said.

She pointed out that water distribution was energy-intensive, accounting for around 30% of the NWSDB’s total operational costs. “Harvesting water at the source significantly reduces the energy and electricity required for pumping and distribution,” she noted. 

In addition, she emphasised its role in flood mitigation. “Collecting rainwater on-site prevents it from overflowing into drains and streets, making it a critical measure during heavy rainfall,” she said. 

Outlining implementation options, Ariyananda said simple residential systems could redirect roof water through gutters into storage tanks placed either above or below ground, with access via hand or electric pumps. For high-rise buildings, she noted that external walls or façades could be used as catchment surfaces, with storage distributed across different levels to enable gravity-fed systems. 

She also highlighted the potential for groundwater recharge: “In areas with existing wells, rainwater can be directed into them to increase water levels and improve quality by reducing salinity.”

Despite these advantages, Ariyananda pointed out that Sri Lanka’s regulatory framework had not been effectively enforced. The country introduced a National Rain Water Policy and Act in 2005, mandating that all new urban buildings constructed after 2009 include harvesting systems, while older buildings were required to retrofit within three years. “However, enforcement remains virtually non-existent, and many institutions continue to waste treated water on non-essential uses such as washing vehicles,” she noted.