I have a one piece shower that is leaking. I have taken the quarter round off around the front of the shower unit and the adjacent base boards and water is slowly seeping out from under the shower. The quarter round trim was very wet. Is there anyway to get the remaining water out from under the shower without removing the whole thing. The shower sits in a small alcove with walls on 3 sides. The quarter round was chalked to the front of the unit and was attached to the trim by nails on the adjacent walls.

Looking in the shower drain, I can see the black rubber ring or gasket and I was told this should have had a plastic flange over it to prevent this type of leak. I was also told to get clear 100% silicone to fill this in and to also chalk around the shower fixture itself as this may be an area that may leak also.

I am drying up the water as it seeps out and have a fan on it. Any suggestions Thanks a lot

If the shower floor "gives" a bit when you step in to take a shower then the base doesn't have the support it needs and will, in time, loosen and break the watertight seal between the drain and the base. In addition the drain was installed incorrectly to begain with. Let me show you how the drain should have been installed, (see image).
First a ring of plumbers putty or silicon Jell around the drain lip and the drain set over the hole in the base. From underneath the black rubber gasket, ( that was incorrectly installed under the lip of the drain.) Then the fiber anti-friction washer and last of all the large nut that secures the drain assembly. But even if the drain's installed correctly if the floor of the base isn't supported you will have a leak sooner or later. My advice? Reinstall the drain correctly and if the shower floor need support brace it up with 2 X4s or puddle cement or mortor under the base for support. Good luck, tom

Thanks for the information