Dual feed irrigation

Call today on a rural property with stock tanks (ponds).
They say the grounds landscape irrigation is a dual feed from city water supply and stock tanks.

I’m thinking due to turbidity, microbial growth, and algae there would have to be some sort of filtration system on the tank feed side.
Other obvious components would be check valve and backflow prevention…
Any thing else???
Anyone familiar with these systems and components, help or information would be appreciated?

Check Texas regs…BUT…most if not all states would require the highest level of backflow prevention on water supplies that are potentially as hazardous as a stock tank w/ fecal matter…

I bet it isn’t installed to code…and I don’t need code to tell me that pumping water from stock tanks and having a dual feed w/ city water is a bad idea…

Proper backflow will limit the contamination possibilities, but will not eliminate them…YEARLY inspections and testing of the backflow device highly recommended…