Usefully timed email today, NS, the Dutch railways, have announced that they are installing a water tap in every station. This gives another useful place to top up with water when our for a ride.
I've found that installing OSMand on my phone, and turning on the water tap POI layer, makes it easy to find water taps when out, not all taps are on there, and not all taps on there are working, but it's better than nothing.
J