The [canal] flushing is necessary because, while most of Amsterdam’s 2,800 houseboats have running water, electricity and gas heat, few are connected to sewerage systems and continue to spill their waste into the canals.

The houseboats’ lack of toilet training is their dirty little secret, one that sits uncomfortably with a new generation of wealthier, more demanding owners who are leading a gentrification of the houseboat scene. In the process, they are displacing the less affluent boat people, many of whom are relics of the 1960s and 1970s era of flower power now struggling to pay the upkeep on their boats.