Public Works Department, Taipei City Government

Toilet paper, tissue paper and paper towel have different ingredients for their purposes. Toilet paper made of short fibers can be easily destroyed when wet, therefore can be flushed down the pan; tissue paper and paper towel are made of longer fibers, they contain additives that tend to clog the drainage, therefore shall not be disposed of in the toilet. 

In houses not yet connected to the sewerage system, drains from the toilet pass through a sewage treatment facility (or septic tank) before getting into the gutter, where treated sludge remains in the facility and requires the user to clear it out periodically. Toilet paper thrown into the toilet tends to increase the sludge amount and results in needing a more frequent pumping-out of soils. 

Users already connected to the sewerage system shall still keep a good habit to verify that only specified toilet paper is allowed to enter the toilet; tissue paper, sanitary pad, rag, bamboo chip, wood strip, and other miscellaneous objects therefore can be flushed down the pan or it will be clogged. Furthermore, either improper piping slope or insufficient pipe diameter in a building may result in a clogged pipeline and cause inconveniences.