When we talk water consumption in regard to bathroom facilities, you might get into the weeds a little bit. In most modern countries, water from waste facilities is not “wasted” and is instead treated and returned to reservoirs or rivers. Upon being returned, the contaminants are diluted by the natural water source and then are eaten and processed by organisms that will rebalance things. And many areas in the US draw from aquifers that are replenished by adding this water back into the ground which takes years and further filters the water.

The reason evaporation is a problem is because we don’t have to consider those complicated factors when the water is returned to the air. It is purely wasted in the sense that it will be dispersed in the air and we have no control over where it goes after that. If you have an abundance of water and your aquifer is at equilibrium, no problem. But if you’re in a desert and having to desalinate water from an ocean to fill your water park, that’s a big issue. Basically it’s hard to know exactly how bad this park would be without context of its resource systems.