Stop Waiting a Year: Fix RimWorld's Broken Moisture Pumps Right Now

Moisture Pump 101

Quick-Start Guide

  • Research: "Moisture Pump" tech (requires Microelectronics)
  • Resources: 75 steel, 4 components, Construction skill 6
  • Power: 150W continuous power
  • Time: ~60 days to reach full radius (~7 tiles)
  • Cannot be moved once placed (vanilla)

Common Questions

It drains moisture from nearby terrain, turning mud, marsh, and shallow water into dry land you can build on. Essentially, it slowly creates soil where there was none. New to RimWorld? Check our complete beginner's guide to learn the fundamentals first.

About 60 in-game days (one year on default settings) to reach its max radius ~6.9 tiles. The effect starts on the tile it's built (instant on that one tile) and spreads roughly 1 tile every 8-9 days.

No. Vanilla pumps cannot dry deep water or running water like rivers/oceans. You'll need mods for that.

Yes, if you have time and a problematic swamp/mud patch. It's basically the only way to permanently solidify land. However, if your base doesn't need that wet area, you can often ignore pumps.

You can build bridges over water and mud for light structures, but for heavy buildings (e.g. stone walls, generators) you either need rock solid ground or special heavy bridges from mods. Moisture pumps create that solid ground for you in vanilla.

How It Works

The pump slowly "equalizes moisture" in the ground around it, converting wet terrain to dry, buildable land:

Moisture Pump Simulator

See how the pump's effects expand over time:

Day: 0

Terrain Conversion Table

Original Terrain After Pump Dries It Fertility Buildable?
Mud, Marsh, Marshy Soil Soil 100% Yes
Soft Sand Sand 10% Yes
Shallow Water/Ocean Stony Soil 70% Yes (rough)
Ice biome - Shallow Water Ice 0% Yes
Deep Water / Rivers Unaffected 0% No

Placement Pro Tip

You can build moisture pumps on wooden bridges! This lets you place them in the middle of a marsh or shallow water, instead of starting from the edges.

Biome Strategies

Moisture pumps work differently depending on your biome. Here's how to use them strategically:

Tropical & Temperate Swamp

Challenge: Tons of mud and marsh restricting building space.

Strategy: Research moisture pumps ASAP. Place pumps on bridges in the largest contiguous marsh areas blocking your expansion. In tropical swamps, target the mud patches between rich soil for farming expansion. For optimal colony layout planning, consider future expansion areas early.

"The first pump is a godsend. It opens up so much space eventually. Yes, you'll be defending a pump out in the open for a while, but once that land dries, you can build proper walls, killboxes, or new farms." - Reddit user

Coastal Flats / Fishing Village

Challenge: Shallow water limiting beach property usage.

Strategy: Set a pump near the shoreline early. It will gradually convert shallow water to stony soil (70% fertility), reclaiming land from the sea.

Defense Note: Draining coastal water removes natural barriers that slow raiders. Consider keeping some water as a defensive moat.

Arid & Extreme Desert

Challenge: Soft sand preventing construction of heavy structures.

Strategy: Moisture pumps can firm up soft sand into normal sand, allowing construction. Pumps are niche in deserts - use them only for critical soft sand spots.

Boreal Forest & Temperate Forest

Challenge: Occasional marshy sections, especially in boreal forests (cold bogs).

Strategy: If your base spans a marsh in a boreal forest, moisture pumps are useful for clearing building space. In temperate forests, you might only need pumps if you spawned on a particularly wet map.

Ice Sheet / Sea Ice

Challenge: Limited buildable space on sea ice with water patches.

Strategy: Moisture pumps turn shallow water into ice (not soil). This creates permanent ice terrain that remains even if temperatures rise. On Sea Ice challenge maps, this can extend your buildable area.

Note: In ice biomes, getting materials and power for a pump is already challenging. Consider this a late-game project. For surviving extreme cold conditions, see our cold weather survival guide.

Multiple Pump Strategy

For fast results in large swamps, use multiple pumps in a grid pattern. Place them 2-3 tiles apart so each pump only needs to expand a couple of tiles to connect with its neighbor's dry area.

This "wealthy terraforming" approach is resource-intensive but drastically reduces wait time compared to a single pump.

Advanced Strategies & Tips

Pro Tips

Instant 1-Tile Dry

A moisture pump instantly dries the tile it's built on. Use this for quick fixes:

Need to build a geothermal generator on mud? Place a pump there briefly, power it, then deconstruct it and build your generator. This technique works for any base building project requiring solid ground.

Bridge Placement Trick

Build wooden bridges into the center of marshes, then place pumps on those bridges.

This lets you start drying from the middle rather than edges, saving months of time.

Pump as Cover

A moisture pump provides 15% cover in combat (equivalent to a tree).

Consider this when placing pumps - they might be useful as minor cover during raids.

Power Management

Pumps require continuous 150W power. They have no on/off toggle.

To stop power drain, disconnect the power line or deconstruct the pump when finished.

Base Planning with Pumps

Phase Planning

Plan your base in phases around future dried areas:

  1. Phase 1: Use available dry land for initial buildings
  2. Phase 2: Place pumps early, use bridges as temporary paths
  3. Phase 3: Once land is dry (~60 days), build permanent structures

Think ahead about where you'll want to expand. Place pumps in strategic locations even if you won't build there for months. For comprehensive expansion planning, consider long-term colony growth.

Defending Moisture Pumps

Pumps are fragile (50 HP) and flammable. Here's how to protect your long-term investment:

  • Build a simple fence or wall around remote pumps
  • Include pumps within your defensive perimeter if possible
  • Keep pumps away from likely combat zones
  • Consider a roof over the pump to prevent weather damage

Wealthy Terraforming

For late-game colonies with abundant resources, try mass-pump terraforming:

  1. Identify a large marsh area you want to dry
  2. Build multiple pumps in a grid pattern (2-3 tiles spacing)
  3. Each pump costs: 75 steel, 4 components, 150W power
  4. Result: Area dries much faster as pumps work simultaneously

Resource-intensive but effective when time matters more than materials.

Mods & Tools

Vanilla moisture pumps are slow but reliable. These mods enhance or replace their functionality:

[WD] Fast Moisture Pumps

Key Features:

  • 4× faster drying (full circle in 15 days vs 60)
  • Increased health (100 HP vs 50 HP)
  • Can be reinstalled/moved like deep drills

Perfect for players who like vanilla mechanics but want less waiting.

Advanced Moisture Pump (Continued)

Key Features:

  • Adds a high-tech pump unlocked after the basic pump research
  • Larger radius (~10 tiles) and faster (10 days)
  • Higher power consumption (450W) and resource cost
  • Can sometimes affect water types that vanilla pumps can't

Great for late-game terraforming projects when you have resources to spare.

TerraPumps

Key Features: Adds multiple pump variants:

  • Reverse Moisture Pump: Creates shallow water (for defensive moats or ponds)
  • Fertilizer Pump: Increases soil fertility using chemfuel
  • Jackhammer Pump: Breaks down rocky terrain into tillable soil
  • Deep Water Pumps: Tools for manipulating water depth

Perfect for players who want complete terraforming control.

Primitive Moisture Pump

Key Features:

  • Available with just Complex Furniture research
  • No electricity required (passive operation)
  • Requires only steel and wood
  • Much slower (90 days) and smaller radius

Ideal for tribal or medieval playthroughs where electricity isn't available.

Terraform RimWorld

A general terraforming mod that lets you directly transform terrain for resource costs.

Unlike pumps, you manually choose exactly which tiles to change. Allows creating terrain that pumps can't, like rich soil or deep water.

Other Helpful Mods

  • Bridges Expanded / Stronger Bridges: Build heavy structures on water without pumping
  • Tilled Soil / Fertile Fields: Improve soil fertility after pumping
  • Almost There!: Speeds up game time during idle periods (helps during long pump waits)

Dev Mode for Impatient Terraformers

If you're not opposed to using developer tools, the "Set Terrain" tool in Dev Mode can instantly change any terrain type.

  1. Open the game console (hit the ~ key)
  2. Enable Dev Mode
  3. Click the "Debug Actions" menu
  4. Choose "Set Terrain..."
  5. Select the desired terrain type and click tiles to change

Note: This is technically cheating, but useful for fixing glitches or as a last resort.