diff --git a/pre_commit/languages/swift.py b/pre_commit/languages/swift.py
index 1c54110c..ef3ffb35 100644
--- a/pre_commit/languages/swift.py
+++ b/pre_commit/languages/swift.py
@@ -1,12 +1,14 @@
 from __future__ import unicode_literals
 
+import os
+
 from pre_commit.languages import helpers
 from pre_commit.util import clean_path_on_failure
 from pre_commit.util import cwd
 from pre_commit.languages import helpers
 from pre_commit.xargs import xargs
 
-ENVIRONMENT_DIR = None
+ENVIRONMENT_DIR = 'swift_env'
 BUILD_DIR = '.build'
 BUILD_CONFIG = 'release'
 
@@ -15,15 +17,23 @@ def install_environment(
         version='default',
         additional_dependencies=(),
 ):
+    directory = repo_cmd_runner.path(helpers.environment_dir(
+        ENVIRONMENT_DIR, 'default',
+    ))
+
     # Build the swift package
-    with clean_path_on_failure(repo_cmd_runner.path(BUILD_DIR)):
+    with clean_path_on_failure(directory):
+        os.mkdir(directory)
         repo_cmd_runner.run((
             'swift', 'build',
             '-C', '{prefix}',
             '-c', BUILD_CONFIG,
-            '--build-path', repo_cmd_runner.path(BUILD_DIR),
+            '--build-path', os.path.join(directory, BUILD_DIR),
         ))
 
 def run_hook(repo_cmd_runner, hook, file_args):
-    with(cwd(repo_cmd_runner.path(BUILD_DIR, BUILD_CONFIG))):
+    directory = repo_cmd_runner.path(helpers.environment_dir(
+        ENVIRONMENT_DIR, 'default',
+    ))
+    with(cwd(os.path.join(directory, BUILD_DIR, BUILD_CONFIG))):
         return xargs(helpers.to_cmd(hook), file_args)