Iron is a plant nutrient, but they don't need very much, so the rusty well water will likely supply more than the plant needs. If you are accumulating lime deposits on your teakettle, or having to clean up lime deposits around your faucets with an acidic cleaner, then you have hard water, and this will raise the soil pH around your blueberry shrubs, eventually. There are indicator dye solutions that can be used to check the pH of your well water, or you can have the water checked by a local lab.

Thanks for the information. I guess I'll try to use rain water instead. The water is definitely hard. I didn't really have to water them much last summer since we had an abundant of rain most of the summer. Trying to get the pH down isn't easy but so far the plants are doing ok.

Here in Madison, we also have hard water, pH is around 7.6. I have been using agricultural sulfur to lower soil pH. It works very well, but it is slow acting, and two years are required for an application of sulfur to be metabolized by soil bacteria, and converted into acid. I have found it necessary to do an annual soil pH test at several locations around the yard, where blueberry shrubs are located. When the pH is between 4 and 5, they grow vigorously.

Not sure how much it will affect pH, but I have a friend who's well water has high iron/rust and it killed their most plants in their garden when using it.

Oh boy! I haven't had to use much well water in the last two years but will keep what you say in mind. I also have pond water that I can access if necessary. I think I better have the water tested to see what it consists of. I know it is safe for drinking because it was tested by the health department when we drilled a new well.

generally if you have plenty organic matter in the soil it will buffer what little minerals are in the water. My water has a 9.2 pH (hard to believe, but it is very hard water) and sure, my garden much prefers rain, but it will still grow with that water.

Manganese and Iron can be heavy in soils and not picked up by plants in oxidative conditions. Manganese needs anaerobic soils like under those wet leaves to be absorbed by plants. Iron just needs oxygen like in dry soils if you have sandy soil it might be time to mulch?

https://youtu.be/Gs9XVPHyWWg