I noticed recently, while using our shower, that water was collecting in the bottom of the stall indicating the drain had a clog and was draining very slowly. I went to the store and not knowing what else to try I went with a well known brand of drain cleaner called Liquid Plumr Professional Strength gel. Liquid Plumr (yes it’s spelled that way) is advertised to clear clogs faster than most other brands. It claims it’s safe for all pipes, septic systems and garbage disposals. It also says it can work in standing water. I have not tried it in standing water. I waited till the water was gone and then used it.
All you do is pour half a bottle of Liquid Plumr Professional Strength down the drain, wait 15 minutes and the flush with hot water. These type of cleaners can be unsafe on the skin so you need to read all warnings and read the whole label.
This worked really well cleaning out the shower drain. I liked that it took only 15 minutes to work on the clog. No more water standing in the shower!