Water in Nairobi's fast-growing satellite towns carries far more dissolved solids than water in the city centre. That is the finding of a field report by iClear Kenya, the Star reported. The water purification firm prepared the report with Shadow Creative Group Limited. It covers 886 readings taken between October 2025 and October 2026.
The South-East corridor around Kitengela, Katani and Athi River averaged 374 milligrams per litre (mg/L) of total dissolved solids (TDS). That is more than twice the 166 mg/L recorded in Nairobi West and Central. Kitengela fared worst, with an average of 546 mg/L. There, 62 per cent of readings exceeded the report's 500 mg/L threshold. Katani averaged 411 mg/L, Syokimau 374 mg/L and Greatwall 361 mg/L.
Central Nairobi had its own problems. One reading there hit 837 mg/L. That shows individual properties can record high levels even in better-served areas. The report warns that "households cannot assume consistent quality at the tap, because source water can vary considerably".
The report links the problem to housing growing faster than investment in infrastructure. Developers keep marketing homes in these areas. Meanwhile, residents face extra costs for water treatment, testing and purification. The report says municipal authorities should consider extending piped, treated water to Kitengela and Athi River. If households rely on private purifiers instead, more of the cost of water falls on homeowners.
iClear says its purification systems cut TDS by 91.2 per cent across the 886 measurements. The Star noted that the gap also creates business for private treatment firms, equipment suppliers and accredited laboratories.
The findings have limits. The readings were taken at iClear customer homes using handheld meters. They are neither independent laboratory tests nor a representative survey of Nairobi households. TDS indicates dissolved mineral levels and does not prove water is unsafe. It cannot detect bacteria, heavy metals or other chemical contaminants.
The report calls for full laboratory testing for fluoride, nitrate, iron and E. coli. It also wants private-sector monitoring data fed into Kenya's national water quality surveillance framework. It argues that household-level testing could catch gaps that conventional monitoring misses.