About R.O. w/membrane desalination

I was wondering if someone can answer a question for me.

If the high pressure pump is doing 42 % of the work and 40% of the sea water is being desalinated, has anyone tried placing the high pressure pump on the fresh water side and have it draw water through the membrane ?

The only reason I am asking this is because water has as much force pushing against a pipe's or membrane's walls (inside of it's pores) as it does moving forward. And if so, then drawing water through the membrane might require less energy than pumping it through.