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Kenya, November 09, 2026 - Nairobi is running short of water again. Nairobi City Water and Sewerage Company has cut production at the Ngethu and Kigoro treatment plants by 35% after water levels fell at Thika/Ndakaini Dam. The utility says below-average rainfall in the dam’s catchment reduced inflows. It has extended rationing across Nairobi and parts of Kiambu, Kajiado and Machakos.
That is the official explanation. It is partly true. But it is not the whole story.
Ndakaini is not an ordinary reservoir. It is Nairobi’s main water bank. The dam holds about 70 million cubic metres at full storage and has historically supplied roughly 430,000 cubic metres of water a day, or about 84% of the city’s supply. When its level falls, Nairobi does not simply lose a little water. It loses the foundation of its supply system.
This is why the current cut matters. Nairobi Water is not reducing production because the treatment plants have stopped working. It is reducing production because there is less raw water to treat. Ngethu draws water from Ndakaini. Kigoro is meant to expand the city’s capacity through the Northern Collector Tunnel. Yet both plants are now producing less because the source itself is under pressure.
The official response is precautionary. Nairobi Water says it is limiting abstraction to preserve reserves and avoid draining the dam too quickly. That is sensible. A dam cannot be treated like a tap. Once storage falls too far, recovery becomes slower and more expensive.
But the decision also reveals how little room Nairobi has. The city was already operating close to the edge of its supply. In 2020, Nairobi Water was reported to be supplying about 525,000 cubic metres daily against demand of about 760,000 cubic metres. That left a gap of roughly 235,000 cubic metres every day.
That gap did not disappear. Nairobi has continued to grow. More homes, apartments, schools, hospitals, factories and businesses need water. Every new connection increases pressure on the same limited sources. When rainfall weakens, the city does not merely face a temporary inconvenience. It faces the consequences of years of demand growing faster than reliable supply.
The Northern Collector Tunnel was supposed to change this. The 12-kilometre tunnel draws water from the Maragua, Gikigie and Irati rivers into Ndakaini. It was designed to add about 140 million litres of water daily. The government later said the tunnel, Kigoro plant and a 55-kilometre pipeline to Gigiri were complete, with an expected addition of about 136,500 cubic metres daily.
That is significant infrastructure. But infrastructure does not end a water crisis by itself. A tunnel can move more water into a dam. It cannot make rain fall. It cannot refill a reservoir whose catchment has received less water. And it cannot guarantee that treated water reaches the people who need it.
This is where the story becomes less visible.
Nairobi Water reported non-revenue water of 48% in its FY 2023/24 audited accounts. Non-revenue water means treated water that is produced but does not generate billed revenue. It includes water lost through leaks, illegal connections, faulty meters, inaccurate billing and other operational failures.
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Put simply, nearly half of the water Nairobi produces may not reach a paying customer in the way it should. That does not mean every litre is physically wasted. Some may be used through unmetered or informal connections. Some may be lost through leaks. Some may be misrecorded. But the effect is the same: the city treats expensive water, then loses a large share of it before it can be properly accounted for.
This changes the meaning of the current shortage. If Nairobi loses nearly half of its treated water, then a 35% production cut does not just reduce supply by 35%. Its impact on households can be sharper because the system is already leaking value and volume before water reaches the tap.
It also raises an uncomfortable question. Residents are being asked to conserve water. They are being told to expect longer periods without supply. But how much of the shortage is caused by rainfall, and how much by water lost in ageing pipes, poor metering, illegal connections and weak enforcement?
The answer is not yet public. Nairobi Water has not released a detailed breakdown of current dam storage, daily inflows, abstraction volumes, plant output or losses. Without those figures, the public is being asked to accept a broad explanation for a crisis that affects daily life.
Rainfall remains important. The Kenya Meteorological Service has forecast above-average rainfall across much of the country during the October–December short rains. If that rain falls in Ndakaini’s catchment, inflows could improve and the dam could begin recovering.
But weather is not a water policy. Nairobi cannot control rainfall. It can control how quickly it draws down its reservoir. It can control leakage. It can repair meters. It can reduce illegal connections. It can disclose how much water the tunnel is delivering. It can show whether new capacity is reaching households or disappearing within the system.
The deeper issue is concentration. Nairobi depends heavily on Ndakaini. When that dam is healthy, the city functions. When it weakens, the entire metropolitan water system becomes fragile. This is not a new problem. It is a structural one.
The current crisis should therefore be read as more than a weather event. It is a warning about a city whose water supply remains narrow, loss-prone and dependent on a single dominant source. New tunnels and treatment plants are necessary. But they are not enough if demand keeps rising, losses remain high and the public cannot see the numbers behind the decisions.
The next few weeks will show whether the shortage is easing. The key indicators will be Ndakaini’s storage level, inflows into the dam, rainfall in the catchment, production volumes at Ngethu and Kigoro, and the actual contribution of the Northern Collector Tunnel.
Until those figures are published, Nairobi residents will continue to experience the crisis in the simplest way possible: a tap that runs dry.