The taste of clean water

When developing a borehole project, one might think that the hardest part is the physical rehabilitation and the siting of the boreholes. However there are many challenges which appear only in the second phase of the project, once the boreholes are providing safe water. We have met one of these challenges when some locals reported that the water from our freshly rehabilitated boreholes is salty and not palatable for few users in our Rwandan project. These feedback were unexpected because the water quality tests carried out by a recognized laboratory showed that all tested parameters are well within the acceptable range. What could have been the problem then?

According to our field team, locals have been drinking warm and dirty water from lakes and pond which might have tasted sweeter than the fresh and clean water coming from the boreholes. Our NGO partner reported about similar experience in other clean water project.

The laboratory has also confirmed that the underlying reason is that groundwater often has higher levels of dissolved solids than surface water because of its contact with aquifer geologic material and more time to dissolve rock and mineral materials. To explore the issue more in-depth, conductivity of the borehole water was tested, which is an indicator of the amount of dissolved salts and used to estimate the amount of total dissolved solids (TDS) rather than measuring each dissolved constituent separately. This is an important parameter for drinking water because high TDS values may result in a ‘salty’ taste to the water.

All our TDS results for our rehabilitated boreholes have been well within the limit and range required in the “WHO Guidelines for Drinking-water Quality, Fourth Edition” and we found it important to share it also with our local borehole users. The issue has been incorporated into the WASH education and community sensitization programme to make sure that people are aware why the borehole water may taste “salty” after years of drinking surface water. The success of the WASH programme is confirmed by the field team and in-country partners but also by the usage survey which now shows 100% usage of the rehabilitated boreholes.

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