So the sign says, though I don’t know of too many people that have drowned while riding a bike along a cycleway.
This section of the Hauraki Rail Trail is 15km long between Waitakaruru and Pipiroa. It can get a little tedious as there isn’t much to see along the way, but it’s flat and there are at least some caches to find now. Be warned there is no shelter whatsoever along the route, it’s going to be hot in summer and cold in winter. Only entrances to this part are at the start and end, though you could take a car over the first two km’s at one end but there is limited parking or turning. Food and toilets near both ends, but nothing in between.