You fill your sprayer and foamer up to the line with cleaner or soap from the refill bag. The rest is topped up with water from your own tap. Refilling is easy. With one refill bag of cleaners, you can refill 10 sprayers. With one refill bag of hand soap, you can refill 4 foamers, and with one refill bag of ZO dish clean, you can fill 5 foamers.