I am trying to find out why a shower pan only has a lip on 3 of the 4 sides of the pan? We had a leak between the pan (side without a lip) and the threshold. Seems like if there were a lip on all four sides this leak would have been avoided.

I've looked at home improvement stores and that's the way they all are... How to keep it from leaking again? Thanks..

You can purchase shower pan that has lip on 1, 2 or 3 sides. Not on 4 sides. One side has to be open and serves as a "curb" or "thresh hold". Seal on that side is accomplished by a rubber sweep seal installed on the bottom of your shower door. Can you post a photo of your situation ? Back to you. Milo

Milo's bang on with his answer. Do you have a ,leak? If so how can you be sure it's the shower pan. Has it been checked? There are ways to check to see if;
1. You have a bad shower pan.
2. You have a ruptured drain seal, **OR**
3. Bad tile grout allowing water to leak behind the shower pan.
All give the same symtems.
We can walk you through all of these checks. Would you like us to? Back to you, Tom