A sewer backup is usually caused by material that builds up inside a sewer pipe eventually slowing and blocking the flow of wastewater. Roots often grow into older sewer pipes through small cracks. These roots form a mat that can catch material. Cooking grease will also stick to anything in contact with the wastewater and can eventually build up into large deposits. These deposits, in turn, catch other material or can break off forming “grease logs” that can block a pipe. In recent years, the use of “flushable” wipes has proven to be a big problem for sewer operations. These wipes do not dissolve in water like toilet paper does, so they often collect along with roots and grease to contribute to clogging formation both in sewer pipes and at the treatment plant.