This sign for westbound motorists on Route 73 in Worcester tells them that they are in the Perkiomen watershed. There is no sign going the other way to tell people they are in the Wissahickon watershed. Is the Perkiomen somehow "better" so that they need a sign to tell people where their water goes when they flush the toilet? What difference does it make anyway? It all ends up in the same place.
Maybe its better to tell people which "Mallshed" they are in, as in "Now leaving the Plymouth Meeting Mallshed and Entering the Montgomery Mallshed". At least thats useful information. We need to know the nearest mall to buy stuff, who cares where the wastewater goes?