Reverse osmosis bụ teknụzụ nkewa akpụkpọ ahụ nke emepụtara na 1980s, nke na-ejikarị ụkpụrụ akpụkpọ anụ semipermeable, na-etinye nrụgide na ngwọta etinyere na usoro osmosis, si otú ahụ na-akpaghasị usoro osmotic eke. N'ihi ya, mmiri na-amalite na-asọpụta site na nke a na-etinyekwu uche ruo na ngwọta na-adịghị ahụkebe. RO dabara maka oke salinity nke mmiri raw ma wepụ ụdị nnu na adịghị ọcha na mmiri nke ọma.