Septic tank
While a properly maintained and located septic tank does not pose any more environmental problems than centralized municipal sewage treatment, certain problems can arise with septic tanks in unsuitable locations. Since septic systems require large drainfields, they are not suitable for densely built areas.
Water supply and sanitation in Kenya
The Citizen Report Card moreover indicates that septic tanks are often used for the disposal of wastewater from flush toilets in Mombasa. Pit latrine users from Nairobi, Kisumu and Mombasa indicated that some wastewater empties into storm sewers, soak-aways and cess pits designed for kitchen waste, thus causing environmental pollution. In 2001 a pollution incident occurred in the town of Embu. Raw sewage was discharged from sewage treatment works into a nearby river and caused the death of 28 people who used the water downstream for domestic purposes.