Is my well water detrimental to plant health?

I had some wierd anomalies happen this year and i wonder if irrigating with well water was the cause.

Here is what i know. Central texas. A lot of limestone under the soil and some rocks at the surface.

The well water is very alkaline and has a sulphur smell. The only way i can quantify the water is with a pool test kit. Where the kit says 8 to 12 is optimum, my readings are 18 to 21. I havent done a ph test but i can.

I have moved toward rain water collection, both in storage tanks and earthworks, and i will continue.

My examples mainly involve metal. A galv stock tank lasts a year before the spot welds rust through. I switched to plastic, but now i can maintain all the tanks with rain water. The slide racks in my dishwasher last a year before they disintegrate. I now have rainwater plumbed into the hotwater side of my house (1,000 gallon tank).

Surely this is not good for plants?

Our water is much the same as you describe yours. Although it initially does not smell of sulfur, it will if sitting in a metal tank. I think it is the result of iron eating bacteria. I have also noticed it will rust tools if they are washed and not oiled. Just from personal observation I would say my plants tolerate it but it's not real great for them. In years where we get a proper monsoon summer, the plants do much better than when I drip irrigate constantly. I think the PH of the water combined with the already extreme alkalinity of my soil is hard on anything that prefers the acid end of the spectrum. My blueberry is sad this year.