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Project Zomboid erosion speed is the sandbox option ErosionSpeed. It sets how many in-game days nature takes to fully reclaim the world: 1 Very Fast (20 days), 2 Fast (50), 3 Normal (100), 4 Slow (200) or 5 Very Slow (500). ErosionDays overrides it with an exact number of days; 0 means “use Erosion Speed”. On a FREAKHOSTING server, both are in <Server Name>_SandboxVars.lua.

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What is erosion in Project Zomboid?

Erosion is the slow takeover of Knox County by nature. As days pass, grass grows over roads, vines climb walls, trees sprout and buildings look abandoned. Full erosion is the point where the world looks fully overgrown.

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Erosion speed values

ErosionDays sets the number of days to full erosion directly, up to 36500 (100 years). Leave it at 0 to use ErosionSpeed. For example, ErosionDays = 1000 makes nature take 1,000 days. Which preset you started with decides the default. In Build 42 the Apocalypse preset uses Slow (200 days).

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How to change erosion speed on your server

Erosion isn’t one of the fields on the Game settings page, so you change it in the sandbox file.
1

Stop the server

Click Stop and wait until the server is offline.
2

Open the sandbox file

In Game settings, click SandboxVars.lua: open the raw file. You can also open Files and go to .cache/Server/<Server Name>_SandboxVars.lua, where <Server Name> is the Server Name startup variable.
3

Edit ErosionSpeed or ErosionDays

Find the lines and change the values, for example:
Keep the comma at the end of each line.
4

Save and start

Click Save Content and start the server.
Sandbox options shape a new world, and some only apply to a world that has not started yet. Set erosion before your players begin for a predictable result. Make a backup before you edit the file.

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Which erosion speed should I use?

  • Short-lived servers or a quick, overgrown look: Very Fast or Fast.
  • Most co-op servers: Normal or Slow.
  • Long-running servers where you want roads clear for a long time: Very Slow, or a large ErosionDays value.

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Frequently asked questions

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How do I turn off erosion in Project Zomboid?

Set a very large ErosionDays, such as 36500. Nature then takes 100 in-game years to fully reclaim the world, so it barely changes.

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What does “erosion days” mean?

ErosionDays is the number of in-game days until full erosion. It overrides ErosionSpeed when it is above 0.

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Is erosion different in Build 42?

The option names and the five speeds are the same in Build 42. The default depends on the preset you start with.

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How do I get full erosion fast?

Set ErosionSpeed = 1 (Very Fast, 20 days) or a small ErosionDays value, such as 10, before the world starts.

Project Zomboid guide

Every Project Zomboid page in one place.

Sandbox settings

World rules, zombies and loot.

Winter server

Run a cold, winter-only world.

Soft reset

Refresh or wipe the map.
Tested by the FREAKHOSTING team on 30 October 2026 (Project Zomboid Build 42 on our Game Panel). Steps may differ slightly if the game or its mods change.

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Need Extra Help?

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Last Updated: October 2026