AWWA SOURCES59207

Although there are numerous anecdotal stories attributing drain-line problems to the use of 1.6- gallon toilets (especially in cases where the drain line services only a single fixture), there is little field data to support these claims. Several laboratory studies of "line carry" have been completed, but most studies caution that the use of sponges, plastic balls, etc., may not accurately simulate "real world" conditions. The intent of this study was to provide science-based data on the effectiveness of popular toilet models to transport solids to the sewer, i.e., drain-line carry. The study involved physically measuring the effectiveness of several different types of ultra-low-flush (ULF) toilet flushing systems to transport a realistic test media (soybean paste and toilet paper) along drain lines installed at different slopes. There is a real need to identify if the installation of ULF toilets, especially in older buildings, can lead to drain line problems, and therefore, flushing performance problems. This project is intended to answer these questions, and thereby enable appropriate policy, code, and economic decisions to be made.