So far, flushable is not too popular with wastewater tweatment operators.
In London, a bus-sized "fat-berg" clogged a sewer over the summer. What was it? A congealed mix of cooking fat and disposable wipes.
The Washington wastewater authority has plenty of company in considering wipes a costly nuisance. Some utilities are striking back. Last month, the city of Wyoming, Minn., filed a federal class-action lawsuit against six makers of pre-moistened flushable wipes for alleged harm to their infrastructure.
In the time it take to supposedly break down, it could already be contributing to problems at sewage treatment plants. Many flushes are already hitting the plants within 1/2 hour, and have not broken down enough in that time to avoid clogging the systems and causing major problems with pumping systems. The FTC already went after one manufacturer. https://www.ftc.gov/news-events/press-releases/2015/05/wet-wipe-manufacturer-agrees-substantiate-flushability