Do you know your tap TDS level?
I checked my tap water this afternoon and was shocked how it has spiked to 705 ppm. (in the past it's been in the 500s.) I don't have a water softener so that's not the problem. I get Phoenix water.
For those who don't know what TDS means, it's basically how much salt is in the water. The lower the better of course.
So, besides the heat, the salty tap water makes growing things all more difficult.
If anyone else has a TDS meter, I'd be curious to see what readings you get from your tap water.