Family size of 1 is given as 108L each, but average usage per member of a family of 2.3 people is given as 89L each, so presumably an average total household usage in Flanders would be about 2.3 x 89 = 205L. I'm not sure where OP gets the 202L number from, it doesn't appear anywhere on the page. Possibly mis-reading a date as a consumption, hence I'm using capital L for Litres.

That's more than 5x less than the US. It's quite plausible the average family size and environmental conditions in Flanders differ quite a bit from that in the US, but it's still a huge disparity, and according to the second link a lot of that seems to be down to domestic irrigation. Tackling that wouldn't be very popular, of course.