diff --git a/docs/new_project_guide.md b/docs/new_project_guide.md
index 416847153..7103c2ac9 100644
--- a/docs/new_project_guide.md
+++ b/docs/new_project_guide.md
@@ -144,6 +144,12 @@ pass them manually to the build tool.
 See [Provided Environment Variables](../infra/base-images/base-builder/README.md#provided-environment-variables) section in
 `base-builder` image documentation for more details.
 
+## Disk space restrictions
+
+Our builders have a disk size of 70GB (this includes space taken up by the OS). Builds must keep peak disk usage below this.
+
+In addition to this, please keep the size of the build (everything copied to `$OUT`) small (<10GB uncompressed) -- this will need be repeatedly transferred and unzipped during fuzzing and run on VMs with limited disk space.
+
 ## Fuzzer execution environment
 
 [This page](fuzzer_environment.md) gives information about the environment that