Water pollution is a rampant problem in most of the developing countries and Kenya is
not an exception. With Kenya also being described as a water scarce country with a projection of
below 400 m3/year per capita which is well below the globally accepted value of 1000m3/year per
capita, there is need for immediate attention to water conservation both in terms of quantity and
quality.
Kiambu county is mostly agricultural with many farms across the county. There are many
streams and rivers that flow across the county and farms bordering them. This exposes the surface
waters to agricultural pollution. The streams also flow across residential areas thus vulnerable to
various forms of pollution including sewage discharges and oils and greases.

Riara river is a small permanent river within Kiambu county with an elevation of 1529
meters (Mapcarta, 2022). With a 4000m3/day supply, the river is dammed for water supply
(KIWASCO, 2022). Across its journey it passes both through farmlands, residential areas and
Kiambu town. It is used for irrigation of coffee farms located within the county. This means the
river is vulnerable to possible agricultural pollution as it flows across farmlands, possible
wastewater discharge mainly in the form of sewage across the residential areas and town, possible
oils, grease and detergent pollution in town.