Skip to content
CharGen Icon
CreatePricing
Dungeons
Sewer · Medium · Medium

Siltwright Drainworks

The first thing you hear beneath the street is water knocking from the other side of a locked door.
Rooms
13
Foes
17, CR 1/8 to 3
Traps
2
Treasure
364 gp
12345678910111213Entrance
Select a room on the plan to open it.

The party is in

1. Street Grate Hall

Seen

Something wanders by

At a glance

The threat

Master Hadrun, once keeper of the lower sluices, now haunts the deepest chamber as a bloated ghast empowered by the tainted runoff.

Wandering monsters (1d3)

  1. 1

    2× Silt-Run RatsCR 1/4

    When: They appear when food is left unattended or when loud fighting echoes through the upper passages.A pair of slick giant rats drag a strip of canvas between them, snapping at anyone who blocks their route.
  2. 2

    Channel OozeCR 1/2

    When: It follows fresh blood or the sound of metal scraping brick.A gray ooze slides along the channel floor, almost invisible beneath the dirty water.
  3. 3

    Pipe CrawlerCR 1

    When: It arrives after a creature has been downed or when the party rests in a corridor.A carrion crawler feels along the walls with its tentacles, seeking a warm body to pull into a pipe recess.

Rooms

13
1

Street Grate Hall

2 foestreasuresecret

What they see

Read aloud

A broad brick receiving chamber sits just below a grated street entrance. Runoff trickles down the north wall, while a draft from the west carries the faint clank of machinery.

Features

  • Iron street ladder ending at a bolted grate
  • Old workbench with silt-clearers' tally marks
  • Several passages lead deeper into the works

What the GM knows

Monsters

2× Sewer RatCR 1/8

Lean sewer rats, unusually bold and slick with black grease.Tactics. They swarm the nearest isolated target, then flee through cracks if one is killed.

Treasure

Silt-clearers' pay box18 gp

A tin pay box contains a few old coins hidden beneath a layer of silt.
Room secrets · GM only

Notes

The normal north door leads toward ; locked passages can be forced or picked. The secret west door is disguised as brickwork and opens to . The rats retreat if offered food, potentially revealing their path.

4 doors: S (normal), N (normal), E (normal), W (normal)

The place

What it is

The Siltwright Drainworks descend beneath the old city in brick galleries, settling rooms, and forgotten service chambers.

Atmosphere

Cold damp air carries the stink of sewage, lamp oil, and old iron.

The threat

Master Hadrun, once keeper of the lower sluices, now haunts the deepest chamber as a bloated ghast empowered by the tainted runoff.

History

The city hired silt-clearers and tanners to build a shared drainage system after years of flooding and disputes over waste.

Rumors

1d4
Roll a rumor

  1. 1A night watchman swears the street grates breathe warm air just before a flood.
  2. 2The old Drainworks were sealed after a fever, but the city still pays someone to oil their gates.
  3. 3A shrine below the streets grants safe passage, provided the traveler leaves something clean behind.
  4. 4A brass key stolen from the archive can open doors that have been bricked over for generations.

Plot hooks

3
InvestigationThe Fevered OutfallA fever has spread through a crowded district, and the city physician believes its source lies in a blocked outlet beneath the old streets. The party must reach the lower sluices and stop the contamination.From: Seshra, a sibilant-speaking district physicianReward: A purse of 100 gp and a healer's kit stocked with rare antitoxins
RescueThe Missing CrewA flood has opened a sealed grate, and a worker's crew has not returned from checking it. Their foreman fears the old maintenance passages have become occupied.From: Borin Kest, a blunt, broad-shouldered foremanReward: A city salvage permit and 75 gp
RecoveryThe Sluice KeyA brass sluice key was stolen from the municipal archive and traced to a buyer seeking access to the Drainworks. The party is hired to recover it before the lower gates are opened.From: Aurelis, an archivist with a measured, flowing mannerReward: The key's listed bounty and one uncommon potion

Corridors

4

  • Main passage between and

    A waist-high flood mark stains the brick, with strands of hair and scraps of cloth caught along its edge.

  • Passage between and

    A narrow maintenance channel runs beside the walkway. Something small skitters through it whenever a light passes.

  • Passage between and

    Copper pipes sweat a faintly sweet vapor; striking one produces a note that can be heard in .

  • Passage approaching

    A chain of rusted bells hangs over a sluice trench. The bells are silent unless the water below rises.

Media

0 images

No images yet.

Visual sheet

Turn Siltwright Drainworks into a sheet

A high-res, share-ready sheet you can post or print.