Many of us are aware of the lack of safe drinking water in many parts of the developing world, including Africa. The main culprit remains water resources that are not protected from enteric bacteria and viruses. A just released study did a meta-analysis of almost 43,000 water samples from 7 countries in sub-Saharan Africa to assess the amount of bacterial contamination and how it varied with respect to source type.

Most of the samples (64%) were from piped supplies, although the majority of people in these countries still rely on non-piped sources (surface water, springs, some dug wells, rainwater). This is in part due to the fact that many if not most non-piped sources are not consistently monitored.

As expected, piped supplies had the lowest levels of fecal indicator bacteria (FIB) compared to other source types. Piped supplies, also known as household or yard connections, are defined as a water service pipe connected with in-house plumbing or public standpipes. I believe this means water provided by a community or private water supplier. Fewer than 4% of samples from these types of sources were contaminated.

Rainwater and borehole (drilled well) sources had the best quality for the other improved sources of water, but even so 22% and 31%, respectively, of those samples tested positive for FIB. (“Improved” means the source is “likely to be protected from outside contamination.”) Samples from protected dug wells were positive for FIB a whopping 65% of the time. And the authors note that since most water sources in sub-Saharan Africa are non-piped, the percentage of people drinking contaminated water is very high. The authors also conclude that improvements in local data collection are critical to making progress toward safe drinking water access.

Kumpel et al., 2016. Environ. Sci. Technol. 2016, 50, 10869−10876.