Low-cost simple water testing for faecal contamination
The best and most common would be the &quot;multiple fermentation tube” or “most probable number” technique. Rather than testing for all pathogenic bacteria, it uses indicator microorganisms to assess the potability of the water. You'll need a lab to do this but if you have access to one, I'm sure that all the needed materials are common there. Here's a copy of the method: https://www.who.int/water_sanitation_health/resourcesquality/wqmchap10.pdf