Water – Pumping water using a small electric pump, does it need to be potable

I suspect you have a set-up like this?

You are concerned that when the water gets pumped back into the "water heater" it could possibly pollute your main water line?

The only thing I could suggest is putting a check valve on the "cold" water supply so that it can only supply fresh water. That is helpful if the pumps output pressure is higher than your supply pressure (This could happen on someday with low supply pressure or if you do not have main water pressure regulator)

In this situation the return is a dedicated port on the "water heater/boiler" and there should already be a check valve/pressure regulator/non return valve just before the water heater. So the rest of the house will run just on the cold water supply and never get any recirculation contamination.

It is not a standard feature. The pump often hooks into a manifold that connects to the pressure tank and that has a check-valve, pressure gauge, pressure switch, tank drain valve, main shutoff valve, and over-pressure relief valve. The assembly looks like the following once assembled (note: check-valve not shown in this setup).

You will have to consult the manufacturer's spec sheets to see if it comes with an integral pressure switch. Even if the manufacturer won't respond, often they have spec sheets and manuals available online that will give you this info.

Note: the bottom pump is a no-brand Chinese manufacture pump, you might be able to trace it through Ali-Baba, but you'll have to take the Amazon description's word for what it does as there's not much else available about it online.