Our filter systems do not use a pump and operate purely on the water pressure in your pipeline. Ceramic water filters work by allowing water to flow through the millions of tiny pores on the ceramic candle shell. These pores which are about 0.5 micron in size, trap impurities as the water passes through them. This causes the water flow rate to reduce. Overtime, the build up of these impurities on the surface of the candle will cause gradual reduction in flow rate. Since ceramic candles are washable and reusable, we advise our customers to remove the candle and wash it to restore the flow rate.