Rat Hills The Rat Hills was the name given to a stretch of coastline a short distance to the south of Waterdeep , often used as a dump by the city . History . When Waterdeep was still young , it was a simple , barren pebble beach that was a favorite spot for ships to land for repairs or take on cargoes like lumber , since even a mile out to sea the water wasn ' t any deeper than five feet . Once the city had grown large enough to suffer from raiders , however , the citizens began to worry that such an easy port was not only a free alternative to using the city ' s harbor , but also an easy place from which to attack . A shanty town sprang up that was soon under the control of the Shadow Thieves . The lords responded swiftly though , ordering the City Guard to clear " the Beach " of its inhabitants , kill any who resisted and maintain a strong patrol to ensure the area remained clear . Under escort , the citizenry began bringing their garbage here rather than burning it directly outside the city walls , though this task was now handled by the Dungsweeper ' s Guild . The piles of garbage earned the place its later name — " Rat Hills " — and covered an area almost 4 miles ( 6 . 4 kilometers ) in length by 1 mile ( 1 . 6 kilometers ) in width . The accumulated waste poisoned the shallow waters and effectively prevented any hostile landing . The Rat Hills Conflagration of the Year of the Shield , 1367 DR , reduced the size of the piles to under 2 miles ( 3 . 2 kilometers ) in length and a quarter of a mile ( 0 . 4 kilometers ) in width . The area was soon growing again by about half an acre per year . But apart from the daily Dungsweepers convoy and the guard patrols along the trade road , everyone left the area alone , owing to the poisonous waters , the infestation of rats , and the various monsters for which the Hills were a haven . Inhabitants . The smell was indescribable ; it foiled all efforts to track by scent and if it wasn ' t so dangerous , then that trait would likely have been exploited by those on the lam . As it was though , despite the Conflagration dispersing many of the area ' s monstrous inhabitants , there were still a great many creatures , living and undead , that resided in the refuse heaps and shallow waters . The most dangerous creature in the hills was probably Hlaavin the doppleganger . Lizardmen from the lizard marsh and kobold s from the Maiden ' s Tomb Tor were at times spotted in the hills in ever - increasing numbers . While the lizardmen were known to be considering building a fortified lair in the hills , the kobolds ' motivations for living in the Hills were unknown . One of the gates out of Undermountain was known to lead to the Hills , dumping adventurers , usually wounded and / or low on magic into the monster - infested and diseased waters of the area . Every night , a contingent of twenty or more men - at - arms , equipped with lances , heavy crossbow s , and personal weapons , supported by at least two cleric s of Torm and a hired wizard ( who often brought along an apprentice ) could be found watching over the Hills to make sure the hungry monsters didn ' t make an incursion into the surrounding area . As well as the poisonous water and the monsters , the Rat Hills were infested with disease . The animals and monsters carried it , the insects that constantly swarmed the Hills carried it , and the water ( both rainwater pools and the seawater ) and of course the dry garbage " land " were infected . Although not the only disease one could catch , the most common one was known as " darkrot " .