Fire department water??

In our town they go around twice a year & flush the hydrants. You don't want to be doing any white laundry those days because all the water is rusty and messy. After a few mins of running, it clears up. But I wouldn't want that rust in my pool. kimrst

I should think filling the pool with the pond water will be fine.

However, you will have to treat it with Bleach to kill all the little beasties living in it, and then filter them out, and add whatever else is required to get the chemistry right.

And you find people on the forum asking how to clear up their own, "Home-made Ponds", all the time.

My town actually has municipal water that comes out of a river, they just clean it up and sell it to us.