Should I use river water on my garden?
How can I test the Abbagadassett River water to know if it is good for my garden?
Kate Garland, Horticultural Professional
If you have a productive well that has been tested or are using a municipal water source, you have the absolute best chance of irrigating with very good water and positive results. You can safely overhead irrigate through a sprinkler with little issues.
Coming out of a river you really don’t know what is going to be in the water today, flowing by in an hour, or tomorrow. Natural contaminants (ex: a dead animal upstream) and synthetic contaminants (ex: an unsound septic tank or leach field) are just a few things that can easily contaminate your irrigation water. If you have to use the river water, my advice would be to water the soil around the plants, but I’d rather see you use well water.
More on food safety in the home garden can be found in this video (water is mentioned around the two min mark).