Hello All, I am hoping to install a raised redi tile shower basin on top of a concrete slab floor. However, I do not have the option of drilling into the concrete slab to install the p-trap. I would like to minimize the step up into the shower. Therefore, what is the smallest size p-trap dimension that I could use in order to make the shower base as close to the original floor as possible? I am hoping to direct the waste flow to a water pump contained inside of the wall and towards the existing waste drain pipe. I am not familiar with plumbing regulations... Thank you