Water in Waterdeep

Fresh, clean water (for drinking and cooking) in Waterdeep comes from deep wells under Castle Waterdeep and under Farwatch Tower, and from shallow wells around the city. These wells are attended at all times by members of the Watch. To deliberately poison or attempt to block access to or fill in one of these wells is an offense punishable by immediate death (i.e. as soon as the offender is within blade#146;s reach).   #147;Spillwater,#148; the not-quite-so-clean water used for bathing and washing of animals, buildings, and equipment, and for the watering of plants, comes from cisterns on the roofs and the cellars of most buildings in Waterdeep; cellar cisterns are fed by sloping catchbasins on roofs, and have gratings to filter out solid debris that finds its way onto the roof out of the collected water as it flows down wall pipes into the cellar; smaller roof-cisterns are merely open-topped basins, and are cleaned often by users below to avoid contact with dead pigeons and the like. Used spillwater is referred to as #147;nightwater,#148; and is used to sluice chamber pots into the sewers.     First: Waterdeep has a very wet climate. Orographic rainfall occurs as cold sea air blowing onshore hits Mount Waterdeep, is forced to rise, and comes over the mountain dumping its water. And filling cisterns all over the city, well-nigh constantly.   Second: Extensive springs arise deep in the Underdark and come to the surface in two places: high on the slopes of Mount Waterdeep (where they are immediately piped, and used in Mirt's Mansion, Castle Waterdeep, Piergeiron's Palace, municipal pumps in the Market, and throughout Sea Ward) and in the face of the cliff forming the eastern boundary of North Ward (where the water descends into narrow pools at the base of the cliff, and is promptly pumped back up into North Ward, and thence by gravity down into Castle Ward, South Ward, and finally Dock Ward [the most poorly-served ward, water-wise]. The Company of Crazed Venturers encountered "water welling up" many times in their explorations of Undermountain, which even in its fragmentary published form (by TSR and subsequently WotC) has its rivers. A lot of the "black areas" on the sprawling dungeon maps are places where water rises through the rock, under pressure, and no "tunneling in" is possible. Adventurers who tried to "dig their way out" of dungeon areas with Ed as DM quite frequently found themselves starting floods, and fleeing until the water found a way to drain down and away.   Third: People use water quite differently than in modern times. Seawater is used to flush privies (yes, by the bucket method), down into sewers that are flushed out by seawater tides. Public bathing occurs mainly on the beach west of Sea Ward (that's why there's a gate in the wall), in the sea, and is usually undertaken (as opposed to picnics and playing, which occur on sunny days) during rains or heavy mists, when naked bathers emerging from the sea can have the salt naturally washed off their bodies by the freshwater mist and rain). Sand-and-water mixtures are used to scour plates, pots, et al, and there are many soaps, what we would call shampoos, and what we would call grease-cutting detergents in use that drive off grease and sea-salt (Lantanna gnomes and many others constantly invent new ones). Much drinking involves beer, wine, juices and milk brought into the city aboard ships and from around the Sword Coast North interior - - so little "straight water" is drunk. Many noble households have "country estates" that they regularly bring wagon-tanks of water into the city from, for family use in their mansions. And finally, the summertime population of Waterdeep is much higher than the wintering-over population, so water demands drop sharply during times when water is apt to be frozen (though those cisterns keep working; Waterdeep has little insulation, and the crush of crowded-together bodies and cooking and guild-work and animal defecation gives off lots of heat, constantly).   Fourth: the same portal spells that hold the "unseen phantom walls" of the city dimensionally "otherwhere," to be summoned around the city when needed, also hold an opening to a huge lake, which would "pour water from the sky" into the statues around the walls of the Field of Triumph (arena), which contain pipes with various gigantic spigots and drain-holes accessible around the outside edges of the walls (so, into wagon-tanks), that drain on down into Undermountain, should drought, a siege, or other extraordinary conditions of water shortage arise. (This backup has never been needed, but did feature in an adventure Ed ran back in 1982, I think, wherein a Watch patrol got "washed down the street" and a group of PC adventurers managed to escape them.)   So there you have it. Lower demand than you posit, using modern real-world habits, and a very large natural supply with magical augmentation. Trust me, Ed thinks of everything. As for your other questions, Eltan is definitely Ed's invention (as is the Flaming Fist), but I'm not sure about the others. I'll add the "where else are they detailed" query to Ed's massive and ever-growing pile, and we'll see.   the same portal spells that hold the "unseen phantom walls" of the city dimensionally "otherwhere," to be summoned around the city when needed, also hold an opening to a huge lake, which would "pour water from the sky" into the statues around the walls of the Field of Triumph (arena), which contain pipes with various gigantic spigots and drain-holes accessible around the outside edges of the walls (so, into wagon-tanks), that drain on down into Undermountain, should drought, a siege, or other extraordinary conditions of water shortage arise. (This backup has never been needed, but did feature in an adventure Ed ran back in 1982, I think, wherein a Watch patrol got "washed down the street" and a group of PC adventurers managed to escape them.)