Accounting for water quality in monitoring access to safe drinking-water as part of the Millennium Development Goals: lessons from five countries
Rob ES Bain, Stephen W Gundry, Jim A Wright, Hong Yang, Steve Pedley & Jamie K Bartram
Volume 90, Number 3, March 2012, 228-235A
Table 4. Effect of study assumptions on the estimated percentage of the population with access to safe drinking-water
|Study assumption||Effect on estimated percentage with access to safe drinking-water|
|No contamination occurred between the water source and the point of use.||Overestimation|
|The percentage of water sources found to comply with WHO drinking-water safety guidelines at a single survey date remained constant for a year.||Overestimation, particularly for nitrates and thermotolerant coliform bacteria|
|All untested types of improved water sourcea complied with WHO drinking-water safety guidelines.||Overestimation|
|All water sources complied with WHO drinking-water safety guidelines on parameters not measured in the RADWQ project.b||Overestimation|
|All unimproved water sources did not comply with WHO drinking-water safety guidelines.||Underestimation|
|No account was taken of household water treatment and safe storage.||Underestimation|
|The percentage of water sources that complied with WHO drinking-water safety guidelines remained constant before and after the RADWQ project.c||Unclear but country-specific|
|The percentage of water sources that complied with WHO drinking-water safety guidelines was the same in urban and rural areas for each source type.||Unclear but country-specific|
RADWQ, Rapid Assessment of Drinking-water Quality; WHO, World Health Organization.
a Types of improved water source used by less than 5% of a country’s population were not sampled during the RADWQ project.
b The RADWQ project tested water sources for the presence of thermotolerant coliform bacteria, fluoride, arsenic and nitrate compounds.
c The RADWQ project was carried out between October 2004 and April 2005.