I don't know if this would work because you didn't give dimensions but you can try a configuration similar to the this

![enter image description here](https://i.sstatic.net/1m7X3.jpg)

You can use the space by the sump pump as storage. Even the towel closet (with the bwv) could be accessible from the sump area instead of from the washroom.

You could try this. 

![enter image description here](https://i.sstatic.net/U6Vln.jpg)

Or this 

![enter image description here](https://i.sstatic.net/i4Tlj.jpg)