Will the installation of HETs lead to drainline and sewer problems due to the reduced water flows?
Since the introduction of the 1.6 gallons per flush toilet in the early 1990s, questions have been raised about whether sufficient water exists to move solid wastes in the building drainlines and in the municipal sewer system. To date, there has been no evidence to show that waste transport problems occur because of the use of the original low-flow toilets. The introduction of HETs in the late 1990s precipitated the same concerns. As a result, a collaboration of water utilities sponsored a full laboratory study to address the issue. The drainline study, completed in 2004, concluded that HETs flushing with as little as 1 gallon provide sufficient water in residential applications to move the waste from the fixtures to the sewer.
