31 May 2011

Finally, good data on sanitation in Tanzania. But it paints a bad picture

For years, the true state of household sanitation in Tanzania has been hidden by bad data. Household surveys have repeatedly found that around 85% of households across most of Tanzania have access to a pit latrine, with around 10% having better facilities (like flush toilets) and around 5% having nothing. This high level of access to basic latrines is a result of Mwl Nyerere's Mtu ni Afya campaign in the 1970s.

But other than providing an opportunity for an interesting history lesson, this statistic was almost useless, as it made no distinction between well constructed, clean pit latrines and filthy, overflowing or uncovered pits. Now, at last, we have better data.

The quality of a pit latrine is important as it can make a big difference to the spread of disease. Official international monitoring of the water and sanitation Millennium Development Goals is done by the WHO-UNICEF Joint Monitoring Programme (JMP), which only counts "improved" sanitation facilities when monitoring progress towards halving the number of people without access to sanitation. This definition (see box below) includes pit latrines with a washable slab, but not those without a slab.

Improved and unimproved sanitation facilities, international definitions

Household surveys in Tanzania have never previously made this distinction. As a result, Tanzania has never been able to report accurately on progress towards the MDG for sanitation. Estimates on progress were just that - estimates - calculated using a combination of assumptions and models based on more detailed data from other countries. Nor has Tanzania ever really been able to assess whether it is making progress on sanitation - are more people getting access to better sanitation or not?

Now, finally, the 2010 Demographic and Health Survey (DHS), published last month and available online (pdf), gives us an answer. This is the first household survey in Tanzania to use the standard international survey questions on household sanitation, and therefore to produce data in line with the JMP definitions of improved and unimproved sanitation given above.

The results are pretty disappointing, well below expectations. Only 12% of Tanzanian households are using an "improved" facility, leaving 88% with an "unimproved" facility. This means we are well below the JMP's past estimates for access to sanitation (based on models and assumptions rather than surveys) - the JMP had previously estimated that 34% had access to "improved" facilities.

This means that around 35 million Tanzania do not have access to the kind of sanitation facilities that provide an effective barrier against disease. It also puts Tanzania well behind neighbouring countries (assuming their data is reliable) - the proportion of households with access to sanitation in Kenya is 31%, Burundi 46%, Uganda 48% and Rwanda 54%, compared to 12% in Tanzania (figures from the JMP website).

The full breakdown from the DHS 2010 is given below, alongside data from two earlier surveys.

No more grey area, but very disappointing new figures (click to enlarge)

Data on household sanitation facilities in Tanzania, from 2010 DHS - click to enlarge

In summary, the survey paints a picture of household sanitation that's far more detailed than previous estimates, but also far worse than expected. Let's hope we can now use this much-improved data to get to grips with the sanitation crisis.