Raw sewage is one of the most dangerous yet overlooked threats choking Kenya’s cities, poisoning our rivers, and putting millions at risk. As urban populations grow, infrastructure hasn’t kept pace. Only about 20% of urban residents are connected to proper sewer systems. The rest? Their waste ends up in open drains, rivers, soak pits, or leaking septic tanks.

In many towns, the situation is grim. Landlords routinely instruct caretakers to empty septic tanks into drainage systems—often at night or during rains to avoid detection. This is not just illegal; it’s deadly. The result is a toxic brew of contamination, disease, and inequality that hits the urban poor hardest and flows downstream, harming communities, farmlands, and ecosystems far beyond city borders.

Take Kikuyu town. A sewer line was installed nearly two years ago, but without a local treatment plant. All sewage flows by gravity into the Nyongara River, a Nairobi River tributary, before being dumped—untreated—into the Dandora ponds in Ruai. These sewer lines often hug the riverbanks, making them vulnerable to leaks and deliberate discharges into water bodies.

Yet people live and farm along these rivers. Smallholder farmers use this polluted water to irrigate crops that end up in local markets. The public consumes vegetables laced with dangerous bacteria like E. coli and Salmonella, often unaware of the health risks. This hidden contamination contributes to outbreaks of typhoid, diarrhoea, and intestinal infections.

In response, Friends of Ondiri Wetland Kenya (FOWK) has taken a community-driven stand against sewer pollution. In Kikuyu, where the wetland forms the source of the Nairobi River, FOWK volunteers conducted night patrols to expose illegal sewage dumping—actions that led to arrests and improved water quality. We also engaged polluting businesses, educated residents, promoted eco-toilets, and restored riparian zones. Our advocacy helped push for the wetland’s legal protection and showed how local action can drive meaningful change.

The Nairobi River, once a vital artery of life, has now become a flowing gutter: choked with sewage, industrial effluent, and solid waste. And it doesn’t stop there. The river feeds into the Athi River and eventually the Indian Ocean at Kilifi’s Sabaki estuary, spreading the damage across counties and ecosystems. Marine life, fisheries, and coastal livelihoods are all under threat because of inland neglect.

There is some light at the end of this very polluted tunnel. President Ruto’s administration has launched the Nairobi River Engineering and Regeneration Program—a bold, multi-agency effort led by the State Department of Housing and Urban Development, Nairobi City County Government, and the Nairobi Rivers Commission. On the ground, the Ministry of Defence and Kenya Defence Forces serve as project managers.

This initiative aims to restore Nairobi’s rivers, reduce raw sewage discharge, and provide alternatives to residents in informal settlements. It includes building over 10,000 affordable housing units and modern market spaces to resettle communities currently contributing to pollution.

At the heart of this effort is the expansion of the Kariobangi Decentralised Sewer Treatment Works, designed to handle up to 90,000 cubic feet of wastewater daily. It’s a crucial step toward sustainable sanitation.

Meanwhile, conditions in informal settlements are dire. Open drains filled with black, foul-smelling wastewater run next to where children play and families cook. The combination of open defecation, poor waste disposal, and crumbling infrastructure creates a public health emergency.

Kenya has about 49 wastewater treatment plants, but many are outdated or poorly maintained. Nairobi’s two main plants—Dandora and Kariobangi—cannot handle the volume of waste they receive. Much of it ends up partially treated or completely raw, back in the environment.

Relying on centralized systems alone is no longer viable. Fast-growing towns like Ngong, Ruiru, Kitengela, Kiambu, Athi River, and Kikuyu urgently need decentralised treatment plants. These smaller, local systems treat waste where it’s generated, reducing the risk of leaks and overflows from long pipelines.

We must also embrace nature-based solutions. Countries like Rwanda are using constructed wetlands to treat wastewater in urban areas—low-cost, low-tech systems that are ideal for peri-urban and informal settings. Kenya must scale up these systems now, not as an afterthought, but as a core strategy.

The legal framework exists—but enforcement is weak. Illegal sewer connections, industrial dumping, and unmanaged waste must face real consequences. Stronger monitoring and inter-agency coordination are essential.

Equally critical is public awareness. Communities must understand the dangers of raw sewage—not just for their health, but for their food, water, and dignity. Kenya could adopt Community-Led Total Sanitation (CLTS) approaches, empowering residents to take control of sanitation in their own neighbourhoods.

Globally, we can learn from leaders like Singapore, where the NEWater program recycles over 98% of wastewater for reuse. Kenya may not be ready for that level of technology, but the core idea holds true: wastewater is not waste—it’s a resource.

This crisis isn’t just about sanitation. It’s about public health, food security, environmental justice, and national development. It poisons our rivers, pollutes our farms, threatens our oceans, and robs urban communities of dignity.

We cannot afford piecemeal solutions. Kenya must act urgently, boldly, and collectively. The time for finger-pointing and half-measures is over. The future of our rivers, our cities, and our children is on the line.

Clean rivers. Safe food. Healthy communities. This must not be a privilege for the few. It must be a right for all.

Mr. Wakogy is the Coordinator, Friends of Ondiri and the Climate Worx Lead, Ondiri Wetland. Email: dwakogy@gmail.com