diff --git a/homeassistant/components/modbus/__init__.py b/homeassistant/components/modbus/__init__.py
index 8e7d1e48e1a..12e2273bf88 100644
--- a/homeassistant/components/modbus/__init__.py
+++ b/homeassistant/components/modbus/__init__.py
@@ -73,9 +73,7 @@ from .const import (
     CONF_RETRIES,
     CONF_RETRY_ON_EMPTY,
     CONF_REVERSE_ORDER,
-    CONF_RTUOVERTCP,
     CONF_SCALE,
-    CONF_SERIAL,
     CONF_STATE_CLOSED,
     CONF_STATE_CLOSING,
     CONF_STATE_OFF,
@@ -92,8 +90,6 @@ from .const import (
     CONF_SWAP_WORD,
     CONF_SWAP_WORD_BYTE,
     CONF_TARGET_TEMP,
-    CONF_TCP,
-    CONF_UDP,
     CONF_VERIFY,
     CONF_WRITE_TYPE,
     DATA_TYPE_CUSTOM,
@@ -114,6 +110,10 @@ from .const import (
     DEFAULT_SCAN_INTERVAL,
     DEFAULT_TEMP_UNIT,
     MODBUS_DOMAIN as DOMAIN,
+    RTUOVERTCP,
+    SERIAL,
+    TCP,
+    UDP,
 )
 from .modbus import ModbusHub, async_modbus_setup
 from .validators import number_validator, scan_interval_validator, struct_validator
@@ -304,7 +304,7 @@ MODBUS_SCHEMA = vol.Schema(
 
 SERIAL_SCHEMA = MODBUS_SCHEMA.extend(
     {
-        vol.Required(CONF_TYPE): CONF_SERIAL,
+        vol.Required(CONF_TYPE): SERIAL,
         vol.Required(CONF_BAUDRATE): cv.positive_int,
         vol.Required(CONF_BYTESIZE): vol.Any(5, 6, 7, 8),
         vol.Required(CONF_METHOD): vol.Any("rtu", "ascii"),
@@ -318,7 +318,7 @@ ETHERNET_SCHEMA = MODBUS_SCHEMA.extend(
     {
         vol.Required(CONF_HOST): cv.string,
         vol.Required(CONF_PORT): cv.port,
-        vol.Required(CONF_TYPE): vol.Any(CONF_TCP, CONF_UDP, CONF_RTUOVERTCP),
+        vol.Required(CONF_TYPE): vol.Any(TCP, UDP, RTUOVERTCP),
     }
 )
 
diff --git a/homeassistant/components/modbus/const.py b/homeassistant/components/modbus/const.py
index ef6d7c3fc32..01e0fdd5e13 100644
--- a/homeassistant/components/modbus/const.py
+++ b/homeassistant/components/modbus/const.py
@@ -39,9 +39,7 @@ CONF_RETRIES = "retries"
 CONF_RETRY_ON_EMPTY = "retry_on_empty"
 CONF_REVERSE_ORDER = "reverse_order"
 CONF_PRECISION = "precision"
-CONF_RTUOVERTCP = "rtuovertcp"
 CONF_SCALE = "scale"
-CONF_SERIAL = "serial"
 CONF_STATE_CLOSED = "state_closed"
 CONF_STATE_CLOSING = "state_closing"
 CONF_STATE_OFF = "state_off"
@@ -58,13 +56,16 @@ CONF_SWAP_NONE = "none"
 CONF_SWAP_WORD = "word"
 CONF_SWAP_WORD_BYTE = "word_byte"
 CONF_TARGET_TEMP = "target_temp_register"
-CONF_TCP = "tcp"
-CONF_UDP = "udp"
 CONF_VERIFY = "verify"
 CONF_VERIFY_REGISTER = "verify_register"
 CONF_VERIFY_STATE = "verify_state"
 CONF_WRITE_TYPE = "write_type"
 
+RTUOVERTCP = "rtuovertcp"
+SERIAL = "serial"
+TCP = "tcp"
+UDP = "udp"
+
 # service call attributes
 ATTR_ADDRESS = "address"
 ATTR_HUB = "hub"
diff --git a/homeassistant/components/modbus/modbus.py b/homeassistant/components/modbus/modbus.py
index e2f1295220f..7cab51f7fe6 100644
--- a/homeassistant/components/modbus/modbus.py
+++ b/homeassistant/components/modbus/modbus.py
@@ -45,16 +45,16 @@ from .const import (
     CONF_PARITY,
     CONF_RETRIES,
     CONF_RETRY_ON_EMPTY,
-    CONF_RTUOVERTCP,
-    CONF_SERIAL,
     CONF_STOPBITS,
-    CONF_TCP,
-    CONF_UDP,
     DEFAULT_HUB,
     MODBUS_DOMAIN as DOMAIN,
     PLATFORMS,
+    RTUOVERTCP,
+    SERIAL,
     SERVICE_WRITE_COIL,
     SERVICE_WRITE_REGISTER,
+    TCP,
+    UDP,
 )
 
 _LOGGER = logging.getLogger(__name__)
@@ -203,10 +203,10 @@ class ModbusHub:
         self._config_delay = client_config[CONF_DELAY]
         self._pb_call = {}
         self._pb_class = {
-            CONF_SERIAL: ModbusSerialClient,
-            CONF_TCP: ModbusTcpClient,
-            CONF_UDP: ModbusUdpClient,
-            CONF_RTUOVERTCP: ModbusTcpClient,
+            SERIAL: ModbusSerialClient,
+            TCP: ModbusTcpClient,
+            UDP: ModbusUdpClient,
+            RTUOVERTCP: ModbusTcpClient,
         }
         self._pb_params = {
             "port": client_config[CONF_PORT],
@@ -215,7 +215,7 @@ class ModbusHub:
             "retries": client_config[CONF_RETRIES],
             "retry_on_empty": client_config[CONF_RETRY_ON_EMPTY],
         }
-        if self._config_type == CONF_SERIAL:
+        if self._config_type == SERIAL:
             # serial configuration
             self._pb_params.update(
                 {
@@ -229,13 +229,13 @@ class ModbusHub:
         else:
             # network configuration
             self._pb_params["host"] = client_config[CONF_HOST]
-            if self._config_type == CONF_RTUOVERTCP:
+            if self._config_type == RTUOVERTCP:
                 self._pb_params["framer"] = ModbusRtuFramer
 
         Defaults.Timeout = client_config[CONF_TIMEOUT]
         if CONF_MSG_WAIT in client_config:
             self._msg_wait = client_config[CONF_MSG_WAIT] / 1000
-        elif self._config_type == CONF_SERIAL:
+        elif self._config_type == SERIAL:
             self._msg_wait = 30 / 1000
         else:
             self._msg_wait = 0
diff --git a/tests/components/modbus/conftest.py b/tests/components/modbus/conftest.py
index 4f2c9b2b778..35688d2f608 100644
--- a/tests/components/modbus/conftest.py
+++ b/tests/components/modbus/conftest.py
@@ -8,9 +8,9 @@ from pymodbus.exceptions import ModbusException
 import pytest
 
 from homeassistant.components.modbus.const import (
-    CONF_TCP,
     DEFAULT_HUB,
     MODBUS_DOMAIN as DOMAIN,
+    TCP,
 )
 from homeassistant.const import (
     CONF_HOST,
@@ -71,7 +71,7 @@ async def mock_modbus(hass, caplog, request, do_config):
     config = {
         DOMAIN: [
             {
-                CONF_TYPE: CONF_TCP,
+                CONF_TYPE: TCP,
                 CONF_HOST: TEST_MODBUS_HOST,
                 CONF_PORT: TEST_PORT_TCP,
                 CONF_NAME: TEST_MODBUS_NAME,
@@ -131,7 +131,7 @@ async def base_test(
         config_modbus = {
             DOMAIN: {
                 CONF_NAME: DEFAULT_HUB,
-                CONF_TYPE: CONF_TCP,
+                CONF_TYPE: TCP,
                 CONF_HOST: TEST_MODBUS_HOST,
                 CONF_PORT: TEST_PORT_TCP,
             },
diff --git a/tests/components/modbus/test_fan.py b/tests/components/modbus/test_fan.py
index 4aa55473737..fb65f737d27 100644
--- a/tests/components/modbus/test_fan.py
+++ b/tests/components/modbus/test_fan.py
@@ -12,10 +12,10 @@ from homeassistant.components.modbus.const import (
     CONF_INPUT_TYPE,
     CONF_STATE_OFF,
     CONF_STATE_ON,
-    CONF_TCP,
     CONF_VERIFY,
     CONF_WRITE_TYPE,
     MODBUS_DOMAIN,
+    TCP,
 )
 from homeassistant.const import (
     CONF_ADDRESS,
@@ -219,7 +219,7 @@ async def test_fan_service_turn(hass, caplog, mock_pymodbus):
     ENTITY_ID2 = f"{FAN_DOMAIN}.{TEST_ENTITY_NAME}2"
     config = {
         MODBUS_DOMAIN: {
-            CONF_TYPE: CONF_TCP,
+            CONF_TYPE: TCP,
             CONF_HOST: TEST_MODBUS_HOST,
             CONF_PORT: TEST_PORT_TCP,
             CONF_FANS: [
diff --git a/tests/components/modbus/test_init.py b/tests/components/modbus/test_init.py
index 9400dd56641..3eb1beb460f 100644
--- a/tests/components/modbus/test_init.py
+++ b/tests/components/modbus/test_init.py
@@ -42,21 +42,21 @@ from homeassistant.components.modbus.const import (
     CONF_INPUT_TYPE,
     CONF_MSG_WAIT,
     CONF_PARITY,
-    CONF_RTUOVERTCP,
-    CONF_SERIAL,
     CONF_STOPBITS,
     CONF_SWAP,
     CONF_SWAP_BYTE,
     CONF_SWAP_WORD,
-    CONF_TCP,
-    CONF_UDP,
     DATA_TYPE_CUSTOM,
     DATA_TYPE_INT,
     DATA_TYPE_STRING,
     DEFAULT_SCAN_INTERVAL,
     MODBUS_DOMAIN as DOMAIN,
+    RTUOVERTCP,
+    SERIAL,
     SERVICE_WRITE_COIL,
     SERVICE_WRITE_REGISTER,
+    TCP,
+    UDP,
 )
 from homeassistant.components.modbus.validators import (
     number_validator,
@@ -206,12 +206,12 @@ async def test_exception_struct_validator(do_config):
     "do_config",
     [
         {
-            CONF_TYPE: CONF_TCP,
+            CONF_TYPE: TCP,
             CONF_HOST: TEST_MODBUS_HOST,
             CONF_PORT: TEST_PORT_TCP,
         },
         {
-            CONF_TYPE: CONF_TCP,
+            CONF_TYPE: TCP,
             CONF_HOST: TEST_MODBUS_HOST,
             CONF_PORT: TEST_PORT_TCP,
             CONF_NAME: TEST_MODBUS_NAME,
@@ -219,12 +219,12 @@ async def test_exception_struct_validator(do_config):
             CONF_DELAY: 10,
         },
         {
-            CONF_TYPE: CONF_UDP,
+            CONF_TYPE: UDP,
             CONF_HOST: TEST_MODBUS_HOST,
             CONF_PORT: TEST_PORT_TCP,
         },
         {
-            CONF_TYPE: CONF_UDP,
+            CONF_TYPE: UDP,
             CONF_HOST: TEST_MODBUS_HOST,
             CONF_PORT: TEST_PORT_TCP,
             CONF_NAME: TEST_MODBUS_NAME,
@@ -232,12 +232,12 @@ async def test_exception_struct_validator(do_config):
             CONF_DELAY: 10,
         },
         {
-            CONF_TYPE: CONF_RTUOVERTCP,
+            CONF_TYPE: RTUOVERTCP,
             CONF_HOST: TEST_MODBUS_HOST,
             CONF_PORT: TEST_PORT_TCP,
         },
         {
-            CONF_TYPE: CONF_RTUOVERTCP,
+            CONF_TYPE: RTUOVERTCP,
             CONF_HOST: TEST_MODBUS_HOST,
             CONF_PORT: TEST_PORT_TCP,
             CONF_NAME: TEST_MODBUS_NAME,
@@ -245,7 +245,7 @@ async def test_exception_struct_validator(do_config):
             CONF_DELAY: 10,
         },
         {
-            CONF_TYPE: CONF_SERIAL,
+            CONF_TYPE: SERIAL,
             CONF_BAUDRATE: 9600,
             CONF_BYTESIZE: 8,
             CONF_METHOD: "rtu",
@@ -255,7 +255,7 @@ async def test_exception_struct_validator(do_config):
             CONF_MSG_WAIT: 100,
         },
         {
-            CONF_TYPE: CONF_SERIAL,
+            CONF_TYPE: SERIAL,
             CONF_BAUDRATE: 9600,
             CONF_BYTESIZE: 8,
             CONF_METHOD: "rtu",
@@ -267,26 +267,26 @@ async def test_exception_struct_validator(do_config):
             CONF_DELAY: 10,
         },
         {
-            CONF_TYPE: CONF_TCP,
+            CONF_TYPE: TCP,
             CONF_HOST: TEST_MODBUS_HOST,
             CONF_PORT: TEST_PORT_TCP,
             CONF_DELAY: 5,
         },
         [
             {
-                CONF_TYPE: CONF_TCP,
+                CONF_TYPE: TCP,
                 CONF_HOST: TEST_MODBUS_HOST,
                 CONF_PORT: TEST_PORT_TCP,
                 CONF_NAME: TEST_MODBUS_NAME,
             },
             {
-                CONF_TYPE: CONF_TCP,
+                CONF_TYPE: TCP,
                 CONF_HOST: TEST_MODBUS_HOST,
                 CONF_PORT: TEST_PORT_TCP,
                 CONF_NAME: f"{TEST_MODBUS_NAME}2",
             },
             {
-                CONF_TYPE: CONF_SERIAL,
+                CONF_TYPE: SERIAL,
                 CONF_BAUDRATE: 9600,
                 CONF_BYTESIZE: 8,
                 CONF_METHOD: "rtu",
@@ -298,7 +298,7 @@ async def test_exception_struct_validator(do_config):
         ],
         {
             # Special test for scan_interval validator with scan_interval: 0
-            CONF_TYPE: CONF_TCP,
+            CONF_TYPE: TCP,
             CONF_HOST: TEST_MODBUS_HOST,
             CONF_PORT: TEST_PORT_TCP,
             CONF_SENSORS: [
@@ -326,7 +326,7 @@ SERVICE = "service"
     [
         {
             CONF_NAME: TEST_MODBUS_NAME,
-            CONF_TYPE: CONF_SERIAL,
+            CONF_TYPE: SERIAL,
             CONF_BAUDRATE: 9600,
             CONF_BYTESIZE: 8,
             CONF_METHOD: "rtu",
@@ -431,7 +431,7 @@ async def mock_modbus_read_pymodbus(
     config = {
         DOMAIN: [
             {
-                CONF_TYPE: CONF_TCP,
+                CONF_TYPE: TCP,
                 CONF_HOST: TEST_MODBUS_HOST,
                 CONF_PORT: TEST_PORT_TCP,
                 CONF_NAME: TEST_MODBUS_NAME,
@@ -505,7 +505,7 @@ async def test_pymodbus_constructor_fail(hass, caplog):
     config = {
         DOMAIN: [
             {
-                CONF_TYPE: CONF_TCP,
+                CONF_TYPE: TCP,
                 CONF_HOST: TEST_MODBUS_HOST,
                 CONF_PORT: TEST_PORT_TCP,
             }
@@ -528,7 +528,7 @@ async def test_pymodbus_close_fail(hass, caplog, mock_pymodbus):
     config = {
         DOMAIN: [
             {
-                CONF_TYPE: CONF_TCP,
+                CONF_TYPE: TCP,
                 CONF_HOST: TEST_MODBUS_HOST,
                 CONF_PORT: TEST_PORT_TCP,
             }
@@ -553,7 +553,7 @@ async def test_delay(hass, mock_pymodbus):
     config = {
         DOMAIN: [
             {
-                CONF_TYPE: CONF_TCP,
+                CONF_TYPE: TCP,
                 CONF_HOST: TEST_MODBUS_HOST,
                 CONF_PORT: TEST_PORT_TCP,
                 CONF_NAME: TEST_MODBUS_NAME,
diff --git a/tests/components/modbus/test_light.py b/tests/components/modbus/test_light.py
index 49bfed3e19a..f679883e908 100644
--- a/tests/components/modbus/test_light.py
+++ b/tests/components/modbus/test_light.py
@@ -11,10 +11,10 @@ from homeassistant.components.modbus.const import (
     CONF_INPUT_TYPE,
     CONF_STATE_OFF,
     CONF_STATE_ON,
-    CONF_TCP,
     CONF_VERIFY,
     CONF_WRITE_TYPE,
     MODBUS_DOMAIN,
+    TCP,
 )
 from homeassistant.const import (
     CONF_ADDRESS,
@@ -219,7 +219,7 @@ async def test_light_service_turn(hass, caplog, mock_pymodbus):
     ENTITY_ID2 = f"{ENTITY_ID}2"
     config = {
         MODBUS_DOMAIN: {
-            CONF_TYPE: CONF_TCP,
+            CONF_TYPE: TCP,
             CONF_HOST: TEST_MODBUS_HOST,
             CONF_PORT: TEST_PORT_TCP,
             CONF_LIGHTS: [
diff --git a/tests/components/modbus/test_switch.py b/tests/components/modbus/test_switch.py
index 3838e7a95d5..302189001c5 100644
--- a/tests/components/modbus/test_switch.py
+++ b/tests/components/modbus/test_switch.py
@@ -13,10 +13,10 @@ from homeassistant.components.modbus.const import (
     CONF_INPUT_TYPE,
     CONF_STATE_OFF,
     CONF_STATE_ON,
-    CONF_TCP,
     CONF_VERIFY,
     CONF_WRITE_TYPE,
     MODBUS_DOMAIN,
+    TCP,
 )
 from homeassistant.components.switch import DOMAIN as SWITCH_DOMAIN
 from homeassistant.const import (
@@ -233,7 +233,7 @@ async def test_switch_service_turn(hass, caplog, mock_pymodbus):
     ENTITY_ID2 = f"{SWITCH_DOMAIN}.{TEST_ENTITY_NAME}2"
     config = {
         MODBUS_DOMAIN: {
-            CONF_TYPE: CONF_TCP,
+            CONF_TYPE: TCP,
             CONF_HOST: TEST_MODBUS_HOST,
             CONF_PORT: TEST_PORT_TCP,
             CONF_SWITCHES: [
@@ -330,7 +330,7 @@ async def test_delay_switch(hass, mock_pymodbus):
     config = {
         MODBUS_DOMAIN: [
             {
-                CONF_TYPE: CONF_TCP,
+                CONF_TYPE: TCP,
                 CONF_HOST: TEST_MODBUS_HOST,
                 CONF_PORT: TEST_PORT_TCP,
                 CONF_SWITCHES: [