Few people are aware that although the sewer pipes in the US are 4",
the discharge outlet in US household toilets is 2"...only 1/2" smaller
than the standard marine toilet discharge (Jabsco is the only mfr who
uses a 1" discharge, and even they finally began offering an "optional"
1.5" discharge fitting).



So the only REAL difference between household and marine toilets is the
way in which they flush...a domestic toilet relies on a siphoning
effect that PULLS bowl contents out of the toilet and into the sewer
pipe, where gravity then takes over. Marine toilets have pumps that
PUSH the bowl contents out of the bowl and through the piping. When the
pumping stops, whatever is in the piping stops moving. That's why it's
very important to flush long enough to move bowl contents ALL the way
to their ultimate destination (tank, treatment device, or thru-hull).



So I suspect it's not the SIZE of the piping in the Middle East that
clogs the toilets, but the DESIGN of both the toilets and the
plumbing...European toilets, which have a 4" discharge that reduces the
siphon "pull" (ever notice how much more slowly toilets in Europe
drain...that you often have to flush twice to clear the bowl?) coupled
with too little help from gravity.



Btw, contrary to popular belief, Sir Thomas Crapper did NOT invent the flush toilet.