diff --git a/pre_commit/languages/docker.py b/pre_commit/languages/docker.py
index 4091492c..9c131198 100644
--- a/pre_commit/languages/docker.py
+++ b/pre_commit/languages/docker.py
@@ -7,9 +7,7 @@ import pre_commit.constants as C
 from pre_commit.hook import Hook
 from pre_commit.languages import helpers
 from pre_commit.prefix import Prefix
-from pre_commit.util import CalledProcessError
 from pre_commit.util import clean_path_on_failure
-from pre_commit.util import cmd_output_b
 
 ENVIRONMENT_DIR = 'docker'
 PRE_COMMIT_LABEL = 'PRE_COMMIT'
@@ -26,21 +24,6 @@ def docker_tag(prefix: Prefix) -> str:  # pragma: win32 no cover
     return f'pre-commit-{md5sum}'
 
 
-def docker_is_running() -> bool:  # pragma: win32 no cover
-    try:
-        cmd_output_b('docker', 'ps')
-    except CalledProcessError:
-        return False
-    else:
-        return True
-
-
-def assert_docker_available() -> None:  # pragma: win32 no cover
-    assert docker_is_running(), (
-        'Docker is either not running or not configured in this environment'
-    )
-
-
 def build_docker_image(
         prefix: Prefix,
         *,
@@ -63,7 +46,6 @@ def install_environment(
 ) -> None:  # pragma: win32 no cover
     helpers.assert_version_default('docker', version)
     helpers.assert_no_additional_deps('docker', additional_dependencies)
-    assert_docker_available()
 
     directory = prefix.path(
         helpers.environment_dir(ENVIRONMENT_DIR, C.DEFAULT),
@@ -101,7 +83,6 @@ def run_hook(
         file_args: Sequence[str],
         color: bool,
 ) -> Tuple[int, bytes]:  # pragma: win32 no cover
-    assert_docker_available()
     # Rebuild the docker image in case it has gone missing, as many people do
     # automated cleanup of docker images.
     build_docker_image(hook.prefix, pull=False)
diff --git a/pre_commit/languages/docker_image.py b/pre_commit/languages/docker_image.py
index 0c51df62..311d1277 100644
--- a/pre_commit/languages/docker_image.py
+++ b/pre_commit/languages/docker_image.py
@@ -3,7 +3,6 @@ from typing import Tuple
 
 from pre_commit.hook import Hook
 from pre_commit.languages import helpers
-from pre_commit.languages.docker import assert_docker_available
 from pre_commit.languages.docker import docker_cmd
 
 ENVIRONMENT_DIR = None
@@ -17,6 +16,5 @@ def run_hook(
         file_args: Sequence[str],
         color: bool,
 ) -> Tuple[int, bytes]:  # pragma: win32 no cover
-    assert_docker_available()
     cmd = docker_cmd() + hook.cmd
     return helpers.run_xargs(hook, cmd, file_args, color=color)
diff --git a/testing/util.py b/testing/util.py
index 4edb7a9e..f556a8dd 100644
--- a/testing/util.py
+++ b/testing/util.py
@@ -5,14 +5,24 @@ import subprocess
 import pytest
 
 from pre_commit import parse_shebang
-from pre_commit.languages.docker import docker_is_running
+from pre_commit.util import CalledProcessError
 from pre_commit.util import cmd_output
+from pre_commit.util import cmd_output_b
 from testing.auto_namedtuple import auto_namedtuple
 
 
 TESTING_DIR = os.path.abspath(os.path.dirname(__file__))
 
 
+def docker_is_running() -> bool:  # pragma: win32 no cover
+    try:
+        cmd_output_b('docker', 'ps')
+    except CalledProcessError:  # pragma: no cover
+        return False
+    else:
+        return True
+
+
 def get_resource_path(path):
     return os.path.join(TESTING_DIR, 'resources', path)
 
diff --git a/tests/languages/docker_test.py b/tests/languages/docker_test.py
index b65b2235..3bed4bfa 100644
--- a/tests/languages/docker_test.py
+++ b/tests/languages/docker_test.py
@@ -1,15 +1,6 @@
 from unittest import mock
 
 from pre_commit.languages import docker
-from pre_commit.util import CalledProcessError
-
-
-def test_docker_is_running_process_error():
-    with mock.patch(
-        'pre_commit.languages.docker.cmd_output_b',
-        side_effect=CalledProcessError(1, (), 0, b'', None),
-    ):
-        assert docker.docker_is_running() is False
 
 
 def test_docker_fallback_user():