Ever since the advent of major sewer construction in the 1850s, the issue of increased solids deposition in
sewers due to changes in domestic wastewater inputs has been frequently debated. Three recent changes
considered here are the introduction of kitchen sink food waste disposers (FWDs); rising levels of inputs
of fat, oil and grease (FOG); and the installation of low-flush toilets (LFTs). In this review these changes
have been examined with regard to potential solids depositional impacts on sewer systems and the
managerial implications. The review indicates that each of the changes has the potential to cause an
increase in solids deposition in sewers and this is likely to be more pronounced for the upstream reaches
of networks that serve fewer households than the downstream parts and for specific sewer features such
as sags. The review has highlighted the importance of educational campaigns directed to the public to
mitigate deposition as many of the observed problems have been linked to domestic behaviour in regard
to FOGs, FWDs and toilet flushing. A standardized monitoring procedure of repeat sewer blockage locations
can also be a means to identify depositional hot-spots. Interactions between the various changes
in inputs in the studies reviewed here indicated an increased potential for blockage formation, but this
would need to be further substantiated. As the precise nature of these changes in inputs have been found
to be variable, depending on lifestyles and type of installation, the additional problems that may arise
pose particular challenges to sewer operators and managers because of the difficulty in generalizing the
nature of the changes, particularly where retrofitting projects in households are being considered. The
three types of changes to inputs reviewed here highlight the need to consider whether or not more or
less solid waste from households should be diverted into sewers.