Dungeon Room Index: Sewers and Water Rooms

Sewers! And other watery places.

At the very beginning of this series I specifically called out water and how I think it can elevate a dungeon. Today, I hope to vindicate that idea.

Here are the rooms:

...and this sneaky devil that I missed on my first pass transcribing my rough notes

Sewers as a category

I love sewer dungeons. 

I think there are a few broad archetypes for dungeons out there: "cave", "prison", "tomb"--many of the room types I've covered so far can readily be expanded into a whole dungeon concept. (Some more readily than others--I'll be impressed if you can make "kitchens" into an entire megadungeon.) For many of those, I think when you pick the broad archetype you can readily come up with actual rooms to stitch together (even if there are just a lot of rooms with more coffins in them). 

I think sewers, on the other hand, are kind of the opposite: I don't really think of a "room" when I think of sewers. Like, not a purpose built space for people to do stuff in. Instead, I think of a sewer as kind of a base layer that you build more interesting, more particular spaces into. Real world sewers--while quite interesting in their own ways!--are a little bit sparse and functional. Fantasy sewers always seem like a place where more is going on for some reason (we'll revisit that at the end...)

I think that's why I decided to bundle other kinds of watery rooms together with sewers. It was a challenge to spit out my usual output of rooms that are just "sewers".  (Plus, it makes for a nice thematic grouping.)

Where there's a well, there's a way

Let's also take a moment to discuss water. I've made a point before of saying how much I like water in my dungeons.

Water is so mundane, yet so magical. It can be calm or active, hot or cold, pure or filthy. It can save your life, or take it. How can we lean into that?

• "Calm" water may simply be quiet, and teeming with living things. Algae, or small creatures. These may be edible, or useful components in potions or remedies.
• "Active" water may be rapid, easily carrying off players or dropped supplies.
• "Hot" water may be hot enough to cause attribute loss on contact. It may produce so much steam that vision is obscured, and flammable things are difficult to keep burning. Even if it's not hot enough to burn, it may be hot enough to spoil the delicate alchemical mixtures you keep in your pack. 
• "Cold" water saps your strength, leaving you exhausted after even brief contact. The shivering alone is enough to make sneaking and finesse difficult.
• "Pure" water is a nice break! Who doesn't need to fill a canteen now and again? Perhaps the water is pure beyond the natural: it has natural healing properties, or is at least an essential component in a special magical mixture.
• "Filthy" water water may be stagnant and full of brain-eating microbes, invisible to the naked eye until disturbed; this makes for a great, simple hazard! Or it may simply be polluted and ripe with disease. Prolonged contact or ingestion will surely leave you sick, and any rations you may have been carrying are definitely not safe to consume anymore.

Even without considering extremes, water is still incredibly gameable:

• Water is an excellent hiding place. Whether it be a player, or a monster, the surface can mask their presence for a surprise attack.
• Water is a difficult terrain. Land dwellers struggle to move and attack effectively in water. And water dwellers may struggle to do the same on land! Greater threats are adept in both. In all cases, the water should be a tool for staging strategies or tactics.
• Water is a great obstacle. Besides the aforementioned hiding monsters, water is noisy if you go splashing around in it, and soaking your backpack sounds like a great way to ruin rations, spellbooks, and the like. (Stow those spell books somewhere nice before you hide underwater for that ambush!) Sneaking while dripping wet sounds pretty annoying, too. Water can also act as a Lock; rooms may be inaccessible (or simply very difficult to access!) because it is totally submerged, either hiding it's presence, or presenting a barrier to entry. Don't make water trivial set dressing!
• Water is a great dungeon shift. If water can block or open a path, then it can be very interesting for water levels to change, and water flows to increase or decrease in intensity. It can be very nerve wracking to explore a space that might flood while you're inside of it!

Let's take a look at those rooms now.

Room notes

Halls

I'm a little surprised at how comparatively popular my Hallways post was. Sewer hallways are a little more fun then the average, so they get a shoutout today.

Sewer tunnels can vary between cramped-basically-just-pipes all the way to roomy halls with plenty of walking space. The common requirement is simply that water flows through them! There are many variations on this, and looking at some real world sewers is helpful.

Throughout a sewer dungeon, there should constantly be pipes--small and large--dumping "fresh" water into the halls (and rooms). Some of these may be wide enough to be traversable, but most need not be.

This intersection was stolen directly from a Dyson Logos sewer dungeon (I must say I'm shocked that this is the first time I'm linking Dyson in this blog). It's a fun intersection. I especially like that in two directions you can continue to walk on "dry" ground, but the third requires getting a little wet.

As a larger point when building sewer dungeons: you can't entirely escape thinking about "where does the water come from". An intersection like this can't, for example, flow in from one direction and flow out in two directions. It's not possible, and it's an immersion break. So you have to give a little thought to how water flows through one of these dungeons.

Flow

Speaking of flow, it can be fun to create places where players can mess with a water dungeon's flow. Taken to an extreme, this might get too video-gamey for your taste, but in small doses it's a great bit of puzzle-fuel.

A simple swinging "door" changes the flow from one tunnel to another. The door can fully close in either position, so regardless of which path you take, you can always close the door behind you.
(Granted, opening and closing this door when there's a constant stream of water pushing against it isn't trivially easy)

An elevated platform, accessible from the north of the room, includes a big portcullis-style crank that raises and lowers a pair of doors, directing the water's flow out of this room. The crank first lowers the open door, then begins opening the second. Yes, this means you could leave both positions closed, and potentially flood this room, creating entirely new flows down the north and/or south hall!

Sewer miscellany

When this hallway overflows, it spills over into a side channel that takes the water... somewhere else. There's a service ladder. Go find out!

(Put plenty of ladders into a sewer dungeon. Ladders sometimes feel weird in other kinds of dungeons, but if anything stairs are probably weirder in this kind of dungeon.)

Sewers are ultimately channeling water somewhere. And it's common for that to be fewer somewheres than the water is coming from. That means the closer you get to wherever this water is going, the wider or deeper channels and tunnels need to get.

In this room, external sources dump water into open "drains"; the water swirls and disappears to who knows where. You might find out if you get pushed in. I think you're missing out on some fun if your sewer dungeon is only one level. Of course, there is some challenge inherent to mapping at multiple levels, and adding the logistics of water flow to track only makes that trickier.

Most of the "entry points" to this room are just pipes too narrow to traverse. Water gathers from myriad sources and flows out into the sewer proper. Why did the builder of this sewer put these nice statues in this confluence?... uh, I wouldn't want to ruin the mystery for you.

Fantastic sewer crossings

Three "halls" pass here, but the outer two are elevated far above. Whether this is a large, open space, or the central space has a much lower ceiling than the outer sections, both are cool in their own ways. Water dumps from elevated side passages and joins existing passages below.

Nice and spacious, hallways enter at upper terraces on the north side, and stairs descend, following the downward flow of the water, to the south side. The water empties out into a deep shaft. There is no bridge, but a few rickety planks could easily be placed over the flow for an improvised crossing. Maybe keep some of those in a chamber nearby... Of course they can always just jump, but there's not a lot of space for getting a running headstart, and surfaces are bound to be little slippery.

These two shafts are vertically joined; the first  is a simple four-way crossing, but water pours heavily down the center shaft from somewhere above. The second is just one possible explanation for where that water is coming from: an intersection on a higher level where water pours from opposite tunnels.

Water floods in from each cardinal direction, pouring down into a large pool before spilling over into a central drain shaft. This could make a nice big central chamber on an upper floor of the dungeon.

Wells

Getting away from strictly "sewer rooms" a bit...

A nice place for a break, or a place to hide, or a secret entrance to another area of the dungeon or nice shortcut--wells are versatile and interesting!

Two wells at opposite ends of a long corridor. Perhaps one of them is suspiciously bricked over.

By the multiple entrances, the conspicuous pillars, and the large open space, we might presume that this well was intended more as some kind of social gathering space. The well has more "prominence" than a simple, functional addition.

Cisterns

At a technical level, the difference between a cistern and a well is that a well is for accessing ground water, and a cistern is for gathering and storing water, usually rainwater. I think, functionally, that means that wells often involve deep shafts you need to drop a bucket in or such like, where a cistern is filled to the top.
So, this simple cistern is just a very deep, stone pit filled to the brim, perhaps from some pipes near the ceiling, constantly dripping. When I see something like this, my first thought is that the cistern has been polluted by some creature that makes it's home in the murky depths. At the very least, there's something valuable at the bottom for someone willing to dive in and get it.

This wide, pillared chamber is inspired by the Basilica Cistern. Truly, the first place you should look for inspiration when building fantasy spaces is the real world! (You just... take all the rare and widespread "interesting" things and cram them up close together.) In game terms, I want rooms like this to be home to something challenging. A giant, devil-toad sitting on glittering treasures under the water. That sort of thing. Or a guard patrol snoozing on the opposite walkway.

Reflection pools

A long pool might not be doing much other than just looking pretty, but that's still more interesting than a big, empty, rectangular room. This room calls back to a previous entry with a fire reflecting ominously over the water. This time it has pillars immediately lining the pool!

Two pools, two perspectives. Statues on either end reflect for viewers on the opposite side. Thematically, I'd like the opposite statues to represent dual perspectives on a similar idea. Light and Dark, Good and Evil, Poverty and Wealth, etc.

Bathhouses

Who doesn't like a nice bath? This simple layout includes two bathing spaces, separated by a wall. (Maybe it's easier to pump water in and out without maintaining two totally separate baths.)

A large bathing area is decorated with upper balconies for mingling. If the bath is nice and hot, the upper area quickly becomes a nice, separated humid space, as the steam rises and gathers on the upper story.

This pair of rooms supported baths of different temperatures: the first, a room with hot water, and the second with a deep pool of cold water. Look into Roman baths; they're quite interesting and the engineering involved was pretty impressive and inspiring!

A simple steam room. Vents in the floor allow heated water to billow up and cloud this room. Benches along the inner chamber of the room for relaxing in the hot, wet air. I think it's pretty compelling to imagine a bathhouse themed dungeon that is magically still pumping out steam and heated and cooled water centuries after it has been abandoned. 

Fountains

This fountain is the dramatic focal point of a long pillared hall. We're a hundred miles from the sea, and deep underground, yet the water spewing from this fountains is salty. The spigot is a grimacing gargoyle with taunting eyes.

The center of this hall is a wide fountain with a tall statue of three water carriers in the center. Each is pouring a pitcher, but at any given time of the day only one pitcher actually has water flowing out of it.

A huge pyramid fills this chamber--evidently the source of all of the water in this dungeon--and the water flows down each successive tier before running out into the rest of the dungeon. Pillars on each terrace hold up a ceiling that mirrors the terracing of the pyramid.

Water treatment

Ok, so these rooms might go nicely with the sewer theme again. A place that gathers waste water may include spaces for treating and purifying that water.

   

The first step in any water treatment process is just trapping large debris. Some kind of grate will catch sticks and leaves and other large objects floating in the water. Presumably it's somebody's job to come and clear that stuff out, and I imagine in a sewer environment that other.... buildup would accumulate at such grates, requiring regular cleanup. (I once started a campaign with player characters going to jail and being lent out as sanitation workers in the city sewers. Good fun!)

This large, but low ceilinged chamber includes long, deep pools, with water rapidly flowing over the top. Sediment is allowed to gather at the bottom of these pools.

Fundamentally, there are just a few principles involved in recycling waste water. You're either trying to separate harmful matter from the water, or kill harmful bacteria. It's interesting stuff if you get the chance to look into it!

In this chamber a sort of rake like rotating construction skims floating matter from the top of the water, pushing it out for collection on the rim of the chamber, where it is whisked away elsewhere. (It occurs to me this construction is admittedly very modern in style. We could also imagine a rectangular chamber with a more primitive setup where workers could wheel a large "rake" from one side of the chamber to the other. Maybe I'll draw that some time and add it here.)

Hanging walkways cross this collection pool, swinging haphazardly on rusty chains. Workers used long poles to stir the water here, to encourage particles to clump together for better filtering at later stages. In the present, some source of ground heat or similar has heated this water to boiling, filling the air around these walkways with hot steam.

Elevated walkways criss-cross between large cylindrical vats. Perhaps the water was treated chemically or magically at this stage, or perhaps the vats were boiled. Maybe they're boiling now. I really like rooms full of steam, y'know?
Given that the main floor of this room is elevated, I imagine the lower sections filled with pipes and valves. Just the sort of space for something predatory to prowl around unseen when you first enter the room.

Sewers as canvas

As I suggested earlier, a true "sewer dungeon" need not just be a sewer. It is interesting and common to embed other kinds of rooms within. In this section, I drew a few previously covered types of rooms as they could manifest in a sewer-dungeon setting.

This Library is surrounded by a dramatic moat, crossed by stone bridges. There are no walls or railings, just open terraces over churning water. It seems like an unwise place to preserve books if you ask me; these shelves are likely full of rotten, moldy tomes. A particularly magical book would hopefully stick out clearly to anyone who bothered to search through the slop.

These Prison cells are arrayed on either side of a large watery channel. The cells are round and cylindrical, perhaps once having been large feeder pipes. Breaking through the bricks at the back of a cell might reveal a secret, long forgotten tunnel!
It would be an interesting measure of added security for this chamber to only be accessible by some kind of sewer raft, and it would be nice for some threatening watery guardian to discourage escape attempts.

A Tomb rests atop a solitary pillar in this deep shaft. Where's the water you say? It pours heavily from above, over the pavillion, forming a veil of water around all sides. (I hope the water is clean... the effect would be quite a bit different with sludgy water.)

I think my post on Shrines already had some very sewer friendly rooms, so this one would fit right at home with them. Water flows in from the east and west, between ornate pillars, before flowing northward through barred passages, past a dramatic statue at the head of the chamber--in this case, a sculpture made of writhing snakes in a roughly humanoid form. One "hand" reaches out expectantly, as if waiting to receive something.

I have to say, I'm surprised that my post on Great Halls is as popular as it is. (I'll have you know I put quite a lot of thought and love into my post on Caverns, and it has received comparatively little love!) But! I do love a good, huge "hall". I imagine a party emerging into this massive chamber, torches held high, only to quickly snuff them when they realize a goblin band is crossing the east-west walkways on the northern end of the chamber with their own torches held aloft. A luck or stealth roll of some kind decides that the goblins have spotted your band, and so they shout and holler and level their bows and slings at you. The massive pillars in between provide only limited cover, as the goblins are now spreading out the length of the walkway, so instead you do your best to dodge, duck, dip, dive, and dodge into an adjacent corridor.
Or, maybe you just need to reach the north exit but some slimy, giant, aquatic beast is napping right there on the bridge.

Ugly step child

The more I look at this the less orginal it feels. The idea is a tall, natural shaft, with a pool at the bottom. Maybe the exit is visible, maybe it's subermged. You probably have to jump down, but I did basically the same thing in my Entrances post.

Oh well. I'm at around 300 rooms now in total. They can't all be winners.

Bonus: sewer dwellers

I think a fantasy sewer naturally supports a little more variety in who or what you might run into. Here are some ideas:

• Large vermin. But don't just use giant, diseased rats (definitely use those, too). I'm thinking big, gross, wall-climbing centipedes that like to sneak up on the ceiling, or cockroaches the size of dogs that hunt in packs.
• Sewer Gators. I want to believe.
• Sewer Octopus. I just find this image really compelling. Mollusks are gross, and sewers are gross. Make this mollusk even more gross by choosing color and texture suitable for living in poop all day. Maybe it can even camouflage itself!
• Bandits/thieves/gangs. In fantasy, a sewer is always a great lair for criminal elements. If you're under a thriving city, it gives them a way of getting around unseen.
• Cults. Fantasy sewers always feel a little more grand than real ones, and one easy explanation is that the sewer architect was a member of some cult, and built in places for them to meet for their dark rituals. Similar benefits to the thieves.
• Moving molds and muck. You know how life is supposed to have sprung up from a primordial soup? What could be more ripe (heehee) for such an occurrence than the swirling refuse of a sewer? The yucky things have clung together into new forms of (gross) life. 
• Mutations. The last one was a sort of "evolution" take, this one is more intentional: a mad wizard type lairs down here and does experiments on animals and vagrants who wander too close, turning them into abominable creatures and setting them loose back into the sewers.
• Cursed outcasts. Is it a cliche for a clan of wererats to live down here? It's a fun trope.
• Swarms of flies. I'm thinking of the flies that hang around piles of dung. Crank that up to 11. No, crank that up to 12. The cloud of flies is so thick you can't see through it, and they like fresh meat just as well when they can get it.
• Giant leeches. I just think they're neat. I hope they don't climb up the pipes.

Bonus: deadly diseases

Don't miss this golden opportunity to kill your players with horrifying diseases. Sewers are usually filthy, horrid places. What better place to catch something deadly? Here are ten:

• Bubbling Death. Itchy, smelly, pus-filled boils begin to appear on the skin the next day; impossible to accurately diagnose until they cover your entire body in d4 days, repulsing everyone you meet. Death in d20+10 days.
• Yawning Death. Beginning the next day, every day you don't spend entirely in bed adds some measure of exhaustion. Three consecutive days without this rest and you won't wake again.
• Spasming Death. Beginning the next day, whenever you fail a check or save of any kind, you are overtaken with violent coughing for several seconds. In d6 more days you cough blood. In d6 more days you literally cough up a lung and die.
• Swirling Death. In d4 days your vision is clouded with swirling lights. Ranged attacks become impossible, and melee attacks and all other tasks requiring clear vision become difficult. In d6 more days you lose your vision completely. d6 weeks later your brain stops functioning. 
• Stiffening Death. In d8 days your legs become stiff, impairing mobility. In d8 more days your arms become stiff, impairing action. In d8 more days your whole body is paralyzed. In d8 more days, you die, your body as hard as a rock.
• Rattling Death. On the d6-th night you wake from a horrible nightmare. In d4 more days, the nightmares become constant, limiting the value of rest, and causing paranoia during the day. (You are extremely skittish, and surprises incapacitate you. In d6 more days you can't even sleep, and eventually die from exhaustion.
• Gluttonous Death. In d4 days you gain an excessive hunger, and must eat twice as much or suffer the effects of lack of rest. In d10 more days even that isn't enough, and you become pale and clammy. You lose of quarter of your vitality daily until dead. When you die, a corpulent white worm slithers out of your throat and slinks into the shadows.
• Enticing Death.  In d4 days you develop a particularly sweet scent. Everyone likes to be around you. In d10 more days you attract animals and creatures that want to eat you. It is impossible to remain hidden from predators, and the creatures stalking you are bigger and more violent, traveling from further distances with each day.
• Violent Death. In d4 days you become constantly irritable, offending everyone you meet. In d6 more days you are compelled to never run from a fight. In d4 more days you fight everything and everyone to the death, without rest, until you are slain.
• Brain Eating Parasite. d6 days to live unless treated by an especially high-caliber professional, or else die suddenly. d8 hours after death your head explodes, scattering deadly spores, spreading the infection to all present.

My pattern here is I like it better when a disease takes a little time to manifest, and progresses in stages. And of course, they should be dramatic and mechanically impactful! For deadly and interesting diseases like this, I don't think you should let them be healed by mundane healing or local healers, either. This is the stuff you need a professional for, or to seek out some lost medical textbook for a cure. 

Maybe I should have come up with some cures that could be the subject of a quest, but this has been left as an exercise for the reader!

Bonus: odd justifications for fantasy sewers

I've alluded to some of these already, but to organize it in one place, here are some reasons why this sewer is so much more interesting than a real sewer:

• Cultist architect. Lots of hidey holes for him and his fellows to sneak around doing shady stuff where prying eyes can't see.
• Self-important ruler. Whoever was in charge thought that nothing with their signature of approval should ever be plain. Including a sewer. So this place is grand. No expenses spared.
• Idealistic city planners. They wanted the sewer environment to be clean and comfortable for whoever needed to work down there. Plenty of space, things to do between shifts--people used to practically live down here.
• Cruel city planners. The poor of the city were deemed too unsightly for more genteel eyes. So they built accommodations down here. Basically its an undercity slum and a sewer at the same time.
• Built on top of old ruins. When they started digging they were surprised just how much stuff was already down here. The sewers wind around existing, more ancient structures.
• A mad wizard did it. I think a really cool, maybe cliche megadungeon concept starts as a sewer, then descends into more traditional, elaborate dungeony environments the deeper you go. The mad wizard had to start somewhere!
• Chaotic, mythic underworld. Deep underground things just get weird. It's a place of imagination and nightmares. And that means exotic sewers.