How can you remove stubborn water stains from a glass shower door?

Use a 50/50 vinegar and water solution .

Try making a mixture of white vinegar and water 50/50 add a dab of blue dawn dish soap and a dab of jet dry

About once a month I use the cleaner they gave me for my glass top stove. Once they are clean, I put rainx on them and I've never had to scrub them again.

buy a bottle of soft scrub and sponge.

i have removed hard water spots and stains from my shower door and outside windows by using Windex glass cleaner and light sanding with a fine grit sanding sponge (made by 3M ) available from Lowes or Home Depot. Wet surface with cleaner then sand lightly. You will simply sand off stains.

use a paste of baking soda and vinegar. Scrub and rinse. I keep a spray bottle of straight vinegar in my shower and spray on the glass and squeegee dry after a shower! It may take a couple scrubbing to get it clean! Use a mr. Clean Magic Eraser also helps! After it is clean..use vinegar spray for keep!!

Mix vinegar with baking soda. It will foam up, so be sure to allow room for that in your container. I applied it with a soft bristled brush in a circular motion onto the glass shower enclosure, left it on for about 30 minutes, then rinsed off. Worked for me! :)

This is my solution: https://www.exquisitelyunremarkable.com/2020/04/how-to-clean-glass-shower-doors.html