A water purification system and method embodying a submerged conduit with a semipermeable surface, thereby leveraging water pressure to cost-effectively and energy-efficiently purify the water that permeates the semipermeable surface. A intake conduit may provide the semipermeable surface, wherein the system contemplates rotating the intake conduit so that as it rotates it engages brushes or blades that clear the semipermeable surface of obstructions.