diff --git a/ci/aarch64-linux-debug.sh b/ci/aarch64-linux-debug.sh
index 06eb503431..b49c47967c 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="$PREFIX" \
diff --git a/ci/aarch64-linux-release.sh b/ci/aarch64-linux-release.sh
index 54b8ae44e3..65bcd5f3ec 100644
--- a/ci/aarch64-linux-release.sh
+++ b/ci/aarch64-linux-release.sh
@@ -26,6 +26,13 @@ export CXX="$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 7a50142404..9d6755848d 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="$PREFIX" \
diff --git a/ci/x86_64-linux-debug.sh b/ci/x86_64-linux-debug.sh
index 17e00478fa..29291989e3 100755
--- a/ci/x86_64-linux-debug.sh
+++ b/ci/x86_64-linux-debug.sh
@@ -26,6 +26,13 @@ export CXX="$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="$PREFIX" \
diff --git a/ci/x86_64-linux-release.sh b/ci/x86_64-linux-release.sh
index d8ca7dacb6..cc78d333bc 100755
--- a/ci/x86_64-linux-release.sh
+++ b/ci/x86_64-linux-release.sh
@@ -26,6 +26,13 @@ export CXX="$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 21b069eded..21e4064869 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" \