I think it’s great you are doing this research and coming to your own judgements on charities. Sorry you didn’t get the feedback you were hoping for previously.
I’m not an expert in this—but I think the risk of post-source contamination is a major driver behind why people think chlorination is the most effective intervention. The chlorine stays in the water so continues be protective whereas unchlorinated water can easily be contaminated from storage/dipping cups/hands before it is drunk.
It’s also worth noting that you can’t assume the water coming out of those boreholes is free from bacteriological contamination in the first place. Often the groundwater can be contaminated, particularly if there are livestock or latrines nearby. Possibly Wells4wellness have data on this, it isn’t that complicated or expensive to do field tests for bacteriological quality. Contaminants like heavy metals are trickier and probably less common.
Thanks Ray! We’ll ask about this, but our understanding is that since Wells4Wellness’ wells are deep and pulling from an aquifer, they shouldn’t be contaminated.
But the point about post-source contamination is a good one! That’s why we switched from just taking GiveWell’s chlorination numbers in our first post, to attempting to use well-specific numbers in this post. Unfortunately it was quite hard to find well-specific numbers, so it’s a bit of a guessing game for now. But we are seeing that Wells4Wellness is cheaper than chlorination, so it can still be the case that chlorination has a larger impact, but Wells4Wellness is as or more effective per dollar
I think it’s great you are doing this research and coming to your own judgements on charities. Sorry you didn’t get the feedback you were hoping for previously.
I’m not an expert in this—but I think the risk of post-source contamination is a major driver behind why people think chlorination is the most effective intervention. The chlorine stays in the water so continues be protective whereas unchlorinated water can easily be contaminated from storage/dipping cups/hands before it is drunk.
E.g. https://www.academia.edu/816567/Household_drinking_water_in_developing_countries_a_systematic_review_of_microbiological_contamination_between_source_and_point_of_use
It’s also worth noting that you can’t assume the water coming out of those boreholes is free from bacteriological contamination in the first place. Often the groundwater can be contaminated, particularly if there are livestock or latrines nearby. Possibly Wells4wellness have data on this, it isn’t that complicated or expensive to do field tests for bacteriological quality. Contaminants like heavy metals are trickier and probably less common.
This survey in Niger (if my French is still up to scratch) suggested that most waterpoints’ water tested positive for coliforms so this could be a major factor.
https://www.pseau.org/outils/ouvrages/winrock_international_resume_des_etudes_sur_les_eaux_souterraines_de_15_communes_de_la_region_de_zinder_2022.pdf
Thanks Ray! We’ll ask about this, but our understanding is that since Wells4Wellness’ wells are deep and pulling from an aquifer, they shouldn’t be contaminated.
But the point about post-source contamination is a good one! That’s why we switched from just taking GiveWell’s chlorination numbers in our first post, to attempting to use well-specific numbers in this post. Unfortunately it was quite hard to find well-specific numbers, so it’s a bit of a guessing game for now. But we are seeing that Wells4Wellness is cheaper than chlorination, so it can still be the case that chlorination has a larger impact, but Wells4Wellness is as or more effective per dollar