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Unchecked pollution of city’s water sources poses health risks to residents

Away from its swanky glass facades, trendy cafes and ultramodern highways, deep into its neighbourhood, Nairobi’s estates convulse in water stress, chaotic settlements and nauseating stench of open sewers.

Hundreds of houses and pit latrines in Kawangware, among other informal estates, discharge raw sludge into Nairobi River and its tributaries. The same water from this river is used by peri-urban farmers downstream — in Njiru and Mwiki — to irrigate vegetables consumed by city dwellers.

Last week, the Nation team traced the Nairobi waterway upstream, from Kangemi, where seemingly clean water flows unadulterated until it reaches areas in Kawangware.


Walking along the river’s bank, from Kawangware towards the city, the water becomes increasingly darker and murkier as raw sludge and debris from Gatina and Congo in Kawangware, and Sodom in Kangemi run into the river at certain points.

More contamination from garage spillage, surface runoff and effluence from surrounding buildings is released into the riverine around the central business district.

Consumers Federation of Kenya (Cofek) secretary-general Stephen Mutoro is categorical that it is criminal for anyone to discharge sewage into a waterway and blames the lapse on the county government’s poor surveillance in efforts to end the mess.

Nairobi’s sewerage infrastructure is old, having been laid over 40 years ago, and constrained in terms of capacity. It is, thus, prone to frequent bursts, which worsen the risks of contamination of water sources.

Mr Mutoro said due to rampant contamination of water sources, urban farming needs to be licensed to curb practices such as using water polluted with sewage.

“This, however, doesn’t happen due to lack of surveillance and enforcement, which are county government responsibilities,” said the Cofek boss.


Environmental Compliance Institute director Gerphas Opondo warned that raw sewage effluent contains industrial and human waste, and other toxic substances that are harmful to health.

“The waste water also contains pathogens that settle on the vegetable leaves since the farmers carry out open field irrigation,” said Mr Opondo.

“Most of the sewage treatment plants in Nairobi rely on anaerobic treatment systems, which do not kill the chemical components contained in the sludge, thus they end up being absorbed by the crops.”

He reckons that the presence of open sewers in the city increases chances of contamination of the available fresh water resources, further dashing any hopes of relying on boreholes.

Contaminated water, according to the World Health Organisation (WHO), is a breeding ground for cholera, dysentery, typhoid and diarrhoea, one of the main killers of children under the age of five.

While the factors driving the sanitation havoc in Nairobi can be described as manifold, environmental experts point to the city’s shambolic water distribution system as a big letdown.

Prof Ratemo Michieka, a veteran environmental scientist at the University of Nairobi, told the Nation that lack of access to clean water is a key factor in the use of waste water for irrigation by peri-urban farmers.


Prof Ratemo, a former National Environment Management Authority director, said many residents were admitted to hospital with cholera in the last few months, which is a pointer to sanitation deficiency.

He added that it is time the government took public health with the seriousness it deserves.

“Most of the water pipes run side by side with sewage pipes. Contamination is likely to happen, especially during construction, when excavators hit and break water and sewer pipes,” said Prof Ratemo, “In addition, surface runoff during the rains mixes with clean water in the burst pipes, resulting in contamination.”

In sections of Umoja, Mathare, Huruma, Eastleigh, Kibera, Mukuru, Kayole and Pipeline, piped water mixes with raw sewage as leaking plastic water pipes run across open sewers.

Since the ability of people to pay the full cost of water depends, as it does with anything for sale, on income, Nairobi’s poor residents have no option but to contend with contaminated water. This is usually at the risk of their own lives.


Less than two months ago, the country was hit by a devastating cholera outbreak that claimed more than six lives in Nairobi alone, while over 400 others were admitted to hospital. Two Cabinet Secretaries and some top government officials were among those who were taken to hospital.

A few eateries were later closed down but the situation returned to normal sooner than later.

However, for those living in the informal estates, life has never been so daunting.

“Sisi tunaishi tu kwa neema ya Mungu (We survive by God’s grace),” Ms Caroline Mwende, a resident of Mukuru slum, said while pointing at a leaking plastic water pipe running side by side an open sewer.

Ms Mwende, a mother of three who is currently battling typhoid, said her family boils water for drinking. She said sometimes they add chlorine to water meant for drinking to purify it.

She said she hopes the government will wage a war on poor sanitation after the doing away with plastic bags.


Mr David Ong’are, the director of compliance and enforcement at Nema, notes that sewage management is a pressing problem in many cities in developing countries, including Kenya. He said the main driver in a city such as Nairobi is exponential population growth and urbanisation.

“Nairobi’s population growth has been accompanied by rapid development of housing units, both informal and formal. The sewerage infrastructure in Nairobi is over 40 years old. This poses two immediate problems — wear due to age, and low capacity to accommodate new connections,” said Mr Onga’re.

He said the capacity constraints had led to the us of septic tanks by many households in the city.

Mr Ong’are said Nema had taken up both dialogue and enforcement with the Nairobi City Water and Sewerage Company (NCWSC). He added that the firm is exploring ways of upgrading the sewerage infrastructure.

“Unfortunately, it is an extremely expensive undertaking and might require a public-private partnership arrangement as one of the options,” Mr Ong’are noted.


A Joint Monitoring Programme for Water Supply and Sanitation conducted by WHO and Unicef in 2015 showed that access to improved water sources in Kenya’s urban areas had plummeted from 92 per cent in 1990 to 82 per cent in 2015.

In rural areas, however, access to water sources increased from 33 per cent to 57 per cent during the same period.

A recent assessment of the NCWSC water conducted by the Water Sector Regulatory Board found that 93 per cent of drinking water samples collected from city taps complied with quality standards, which should make the commodity very safe for consumption.

But Lartech Africa managing director Lamarck Oyath argues that because most Nairobi residents get water from the NCWSC on countable days or do not get it at all, it means they get most of their supply of the commodity from vendors.

“But who knows where these vendors get their water and who regulates them?” asked Mr Oyath.


While the NCWSC has an option of hiring suppliers to distribute water to areas it cannot access, the firm has failed to do so, and, instead, remained complacent, leaving the opportunity for a takeover by cartels.

In some instances, the cartels close valves in certain areas to create artificial water shortages to make business for their vendors, according to Mr Mutoro.

Nairobi Deputy Governor Polycarp Igathe last month claimed that the NCWSC has seven regional managers who are also the same owners of water tankers and sewage trucks.

“The same tankers transporting water also carry sewage, which worsens the risks of water contamination,” said Mr Igathe during a televised debate by candidates for the deputy governor posts.

Attempts to get comment from City Hall did not yield results.