Help with tomatoes in Cambodia for orphanage

[GpsFrontier]

1. Is it absolutely necessary to test and control the water? If so, what is the minimum testing we need to do? Do we need to test for biological agents (plant viruses and bacteria)?

2. Do we need to treat water for viruses, bacteria, etc.? If so, we need a very cheap way to do that in Cambodia.

I'm not in Cambodia, but yes you do need good quality water. Not sure where you can get anything tested there, but I would start by filtering the water with a sediment filter. Then to get rid of any pathogens, bacteria, fungus and any micro organisms, simply boil the water for a minimum of 2-5 minutes, that will kill anything living in the water. Once it cools down to room temp, then I would filter it with a carbon filter, like the ones for making drinking water. Your water should be fine to use then.