washer bottle is a receptacle used to hold water or washer fluid for the front and rear windscreen of the vehicle. When the driver fills up the washer bottle he/she must ensure that the cap is replaced. The washer bottle is attached to the washer pump via thin plastic tubing. When the windscreen wipers are turned on, either by the driver or automatically, the washer pump begins pumping water from the washer bottle. The water or washer fluid is then pushed through the thin tubing to the washer jets and sprays out on to the front or rear windscreen. These washer jets are small metal nozzles with black rubberised protective covers that help prevent them from corrosion. The water or washer fluid from the jets is then used by the windscreen wipers to clean the windscreen.

If a crack appears in a washer bottle it may leak water or washer fluid. If this crack is big enough or is left for a long period of time the fluid/water will leak out of the washer bottle meaning none is left for cleaning the windscreens. Dirty windscreens can cause driver visibility issues.