diff --git a/ci/aarch64-linux-debug.sh b/ci/aarch64-linux-debug.sh
index 06eb5034317cbe7cba3d50a4694532e932dbe30b..b49c47967c98704ac4a6363cb6f6264b22ebfbf7 100644
--- a/ci/aarch64-linux-debug.sh
+++ b/ci/aarch64-linux-debug.sh
@@ -26,6 +26,13 @@ export CXX="$ZIG c++ -target $TARGET -mcpu=$MCPU"
 rm -rf build-debug
 mkdir build-debug
 cd build-debug
+
+# Override the cache directories because they won't actually help other CI runs
+# which will be testing alternate versions of zig, and ultimately would just
+# fill up space on the hard drive for no reason.
+export ZIG_GLOBAL_CACHE_DIR="$(pwd)/zig-global-cache"
+export ZIG_LOCAL_CACHE_DIR="$(pwd)/zig-local-cache"
+
 cmake .. \
   -DCMAKE_INSTALL_PREFIX="stage3-debug" \
   -DCMAKE_PREFIX_PATH="$PREFIX" \
diff --git a/ci/aarch64-linux-release.sh b/ci/aarch64-linux-release.sh
index 54b8ae44e3a5e3b35892b32de1bdcda08b32c1a7..65bcd5f3ec8ce4b5927d248682efe9254fc24e89 100644
--- a/ci/aarch64-linux-release.sh
+++ b/ci/aarch64-linux-release.sh
@@ -26,6 +26,13 @@ export CXX="$ZIG c++ -target $TARGET -mcpu=$MCPU"
 rm -rf build-release
 mkdir build-release
 cd build-release
+
+# Override the cache directories because they won't actually help other CI runs
+# which will be testing alternate versions of zig, and ultimately would just
+# fill up space on the hard drive for no reason.
+export ZIG_GLOBAL_CACHE_DIR="$(pwd)/zig-global-cache"
+export ZIG_LOCAL_CACHE_DIR="$(pwd)/zig-local-cache"
+
 cmake .. \
   -DCMAKE_INSTALL_PREFIX="stage3-release" \
   -DCMAKE_PREFIX_PATH="$PREFIX" \
diff --git a/ci/aarch64-macos.sh b/ci/aarch64-macos.sh
index 7a50142404f0c85eeb124fe0a6a1ff3d627f0b21..9d6755848db281b6543d84e82687af9fcafde4ba 100755
--- a/ci/aarch64-macos.sh
+++ b/ci/aarch64-macos.sh
@@ -23,6 +23,13 @@ git fetch --tags
 
 mkdir build
 cd build
+
+# Override the cache directories because they won't actually help other CI runs
+# which will be testing alternate versions of zig, and ultimately would just
+# fill up space on the hard drive for no reason.
+export ZIG_GLOBAL_CACHE_DIR="$(pwd)/zig-global-cache"
+export ZIG_LOCAL_CACHE_DIR="$(pwd)/zig-local-cache"
+
 PATH="$HOME/local/bin:$PATH" cmake .. \
   -DCMAKE_INSTALL_PREFIX="stage3-release" \
   -DCMAKE_PREFIX_PATH="$PREFIX" \
diff --git a/ci/x86_64-linux-debug.sh b/ci/x86_64-linux-debug.sh
index 17e00478fa01463f87b1524e85c15780b1857d8b..29291989e3236f7f18e3ecec65bced6b4970acf5 100755
--- a/ci/x86_64-linux-debug.sh
+++ b/ci/x86_64-linux-debug.sh
@@ -26,6 +26,13 @@ export CXX="$ZIG c++ -target $TARGET -mcpu=$MCPU"
 rm -rf build-debug
 mkdir build-debug
 cd build-debug
+
+# Override the cache directories because they won't actually help other CI runs
+# which will be testing alternate versions of zig, and ultimately would just
+# fill up space on the hard drive for no reason.
+export ZIG_GLOBAL_CACHE_DIR="$(pwd)/zig-global-cache"
+export ZIG_LOCAL_CACHE_DIR="$(pwd)/zig-local-cache"
+
 cmake .. \
   -DCMAKE_INSTALL_PREFIX="stage3-debug" \
   -DCMAKE_PREFIX_PATH="$PREFIX" \
diff --git a/ci/x86_64-linux-release.sh b/ci/x86_64-linux-release.sh
index d8ca7dacb6ee247e1bb26943e13a5f1bf12a3127..cc78d333bc10be06e52335afe01add920378457c 100755
--- a/ci/x86_64-linux-release.sh
+++ b/ci/x86_64-linux-release.sh
@@ -26,6 +26,13 @@ export CXX="$ZIG c++ -target $TARGET -mcpu=$MCPU"
 rm -rf build-release
 mkdir build-release
 cd build-release
+
+# Override the cache directories because they won't actually help other CI runs
+# which will be testing alternate versions of zig, and ultimately would just
+# fill up space on the hard drive for no reason.
+export ZIG_GLOBAL_CACHE_DIR="$(pwd)/zig-global-cache"
+export ZIG_LOCAL_CACHE_DIR="$(pwd)/zig-local-cache"
+
 cmake .. \
   -DCMAKE_INSTALL_PREFIX="stage3-release" \
   -DCMAKE_PREFIX_PATH="$PREFIX" \
diff --git a/ci/x86_64-macos.sh b/ci/x86_64-macos.sh
index 21b069eded46a8ef36fc0b09d5cbe0f9ce4a668c..21e4064869c14d0aeffc304417b932f2c3ac346c 100755
--- a/ci/x86_64-macos.sh
+++ b/ci/x86_64-macos.sh
@@ -29,8 +29,16 @@ git config core.abbrev 9
 git fetch --unshallow || true
 git fetch --tags
 
+rm -rf build
 mkdir build
 cd build
+
+# Override the cache directories because they won't actually help other CI runs
+# which will be testing alternate versions of zig, and ultimately would just
+# fill up space on the hard drive for no reason.
+export ZIG_GLOBAL_CACHE_DIR="$(pwd)/zig-global-cache"
+export ZIG_LOCAL_CACHE_DIR="$(pwd)/zig-local-cache"
+
 cmake .. \
   -DCMAKE_INSTALL_PREFIX="stage3-release" \
   -DCMAKE_PREFIX_PATH="$PREFIX" \