How Robotic Pool Cleaners Work
The basic mechanics: independent motors, onboard filtration, and how they move around a pool.
A robotic pool cleaner is a self-contained unit: it has its own electric motors, its own filtration, and — for corded models — its own low-voltage power supply that plugs into a wall outlet, converting standard household current to a safe voltage for underwater use. Unlike a suction-side or pressure-side cleaner, it doesn't rely on your pool's main pump and filter system at all. See our comparison of robotic, suction, and pressure cleaners for how that changes setup and running cost.
The basic cycle
Once submerged, the robot drives along the pool floor (and, on models built for it, up the walls toward the waterline) using one or more brushed or brushless motors. Rotating or oscillating brushes scrub debris and biofilm loose from the surface, while an internal pump draws water and loosened debris through an onboard filter — a cartridge, basket, or bag, depending on the model — before returning clean water to the pool. Nothing is discharged into your main filtration system.
Getting around the pool
How a robot decides where to go next varies a lot by model and price point, from simple random-bounce patterns to camera- and sensor-based mapping that builds a path covering the whole pool in fewer passes. We break down the specific approaches in our navigation technologies guide.
Corded vs. cordless
Corded models draw power continuously through a floating cable, so runtime is only limited by the cleaning cycle you set. Cordless models run on a rechargeable battery, trading an unlimited runtime for a cable-free setup — see cordless vs. corded for the full comparison.
What it actually cleans
Every model cleans the pool floor at minimum. Beyond that, coverage varies by design: some add wall climbing, some add waterline scrubbing (removing the oily line that forms where water meets tile), and a few add surface skimming for floating debris. We record each model's confirmed coverage on its own product page — never assumed, only what the manufacturer or a retailer states directly.