diff --git a/homeassistant/components/bom/sensor.py b/homeassistant/components/bom/sensor.py
index 8386409d3ea..59ee8027180 100644
--- a/homeassistant/components/bom/sensor.py
+++ b/homeassistant/components/bom/sensor.py
@@ -20,6 +20,7 @@ from homeassistant.const import (
     CONF_MONITORED_CONDITIONS,
     CONF_NAME,
     LENGTH_KILOMETERS,
+    LENGTH_METERS,
     SPEED_KILOMETERS_PER_HOUR,
     TEMP_CELSIUS,
     UNIT_PERCENTAGE,
@@ -73,7 +74,7 @@ SENSOR_TYPES = {
     "rel_hum": ["Relative Humidity", UNIT_PERCENTAGE],
     "sea_state": ["Sea State", None],
     "swell_dir_worded": ["Swell Direction", None],
-    "swell_height": ["Swell Height", "m"],
+    "swell_height": ["Swell Height", LENGTH_METERS],
     "swell_period": ["Swell Period", None],
     "vis_km": [f"Visability {LENGTH_KILOMETERS}", LENGTH_KILOMETERS],
     "weather": ["Weather", None],
diff --git a/homeassistant/components/darksky/sensor.py b/homeassistant/components/darksky/sensor.py
index e4471b7e55f..ab639b2e6a2 100644
--- a/homeassistant/components/darksky/sensor.py
+++ b/homeassistant/components/darksky/sensor.py
@@ -15,6 +15,7 @@ from homeassistant.const import (
     CONF_MONITORED_CONDITIONS,
     CONF_NAME,
     CONF_SCAN_INTERVAL,
+    LENGTH_CENTIMETERS,
     LENGTH_KILOMETERS,
     SPEED_KILOMETERS_PER_HOUR,
     SPEED_METERS_PER_SECOND,
@@ -128,11 +129,11 @@ SENSOR_TYPES = {
     ],
     "precip_accumulation": [
         "Precip Accumulation",
-        "cm",
+        LENGTH_CENTIMETERS,
         "in",
-        "cm",
-        "cm",
-        "cm",
+        LENGTH_CENTIMETERS,
+        LENGTH_CENTIMETERS,
+        LENGTH_CENTIMETERS,
         "mdi:weather-snowy",
         ["hourly", "daily"],
     ],
diff --git a/homeassistant/components/garmin_connect/const.py b/homeassistant/components/garmin_connect/const.py
index 3b8d99c486a..3c30340fc61 100644
--- a/homeassistant/components/garmin_connect/const.py
+++ b/homeassistant/components/garmin_connect/const.py
@@ -1,6 +1,7 @@
 """Constants for the Garmin Connect integration."""
 from homeassistant.const import (
     DEVICE_CLASS_TIMESTAMP,
+    LENGTH_METERS,
     MASS_KILOGRAMS,
     TIME_MINUTES,
     UNIT_PERCENTAGE,
@@ -32,7 +33,13 @@ GARMIN_ENTITY_LIST = {
         False,
     ],
     "netCalorieGoal": ["Net Calorie Goal", "cal", "mdi:food", None, False],
-    "totalDistanceMeters": ["Total Distance Mtr", "m", "mdi:walk", None, True],
+    "totalDistanceMeters": [
+        "Total Distance Mtr",
+        LENGTH_METERS,
+        "mdi:walk",
+        None,
+        True,
+    ],
     "wellnessStartTimeLocal": [
         "Wellness Start Time",
         "",
@@ -48,7 +55,13 @@ GARMIN_ENTITY_LIST = {
         False,
     ],
     "wellnessDescription": ["Wellness Description", "", "mdi:clock", None, False],
-    "wellnessDistanceMeters": ["Wellness Distance Mtr", "m", "mdi:walk", None, False],
+    "wellnessDistanceMeters": [
+        "Wellness Distance Mtr",
+        LENGTH_METERS,
+        "mdi:walk",
+        None,
+        False,
+    ],
     "wellnessActiveKilocalories": [
         "Wellness Active KiloCalories",
         "kcal",
@@ -81,8 +94,20 @@ GARMIN_ENTITY_LIST = {
         None,
         True,
     ],
-    "floorsAscendedInMeters": ["Floors Ascended Mtr", "m", "mdi:stairs", None, False],
-    "floorsDescendedInMeters": ["Floors Descended Mtr", "m", "mdi:stairs", None, False],
+    "floorsAscendedInMeters": [
+        "Floors Ascended Mtr",
+        LENGTH_METERS,
+        "mdi:stairs",
+        None,
+        False,
+    ],
+    "floorsDescendedInMeters": [
+        "Floors Descended Mtr",
+        LENGTH_METERS,
+        "mdi:stairs",
+        None,
+        False,
+    ],
     "floorsAscended": ["Floors Ascended", "floors", "mdi:stairs", None, True],
     "floorsDescended": ["Floors Descended", "floors", "mdi:stairs", None, True],
     "userFloorsAscendedGoal": [
diff --git a/homeassistant/components/isy994/sensor.py b/homeassistant/components/isy994/sensor.py
index c8c427a5bf5..bc213d805ce 100644
--- a/homeassistant/components/isy994/sensor.py
+++ b/homeassistant/components/isy994/sensor.py
@@ -5,7 +5,9 @@ from typing import Callable
 from homeassistant.components.sensor import DOMAIN
 from homeassistant.const import (
     CONCENTRATION_PARTS_PER_MILLION,
+    LENGTH_CENTIMETERS,
     LENGTH_KILOMETERS,
+    LENGTH_METERS,
     MASS_KILOGRAMS,
     POWER_WATT,
     SPEED_KILOMETERS_PER_HOUR,
@@ -35,7 +37,7 @@ UOM_FRIENDLY_NAME = {
     "1": "amp",
     "3": f"btu/{TIME_HOURS}",
     "4": TEMP_CELSIUS,
-    "5": "cm",
+    "5": LENGTH_CENTIMETERS,
     "6": "ft³",
     "7": f"ft³/{TIME_MINUTES}",
     "8": "m³",
@@ -66,7 +68,7 @@ UOM_FRIENDLY_NAME = {
     "35": "l",
     "36": "lx",
     "37": "mercalli",
-    "38": "m",
+    "38": LENGTH_METERS,
     "39": "m³/hr",
     "40": SPEED_METERS_PER_SECOND,
     "41": "mA",
diff --git a/homeassistant/components/mysensors/sensor.py b/homeassistant/components/mysensors/sensor.py
index e528d7c4baa..3e9d39fa64b 100644
--- a/homeassistant/components/mysensors/sensor.py
+++ b/homeassistant/components/mysensors/sensor.py
@@ -3,6 +3,7 @@ from homeassistant.components import mysensors
 from homeassistant.components.sensor import DOMAIN
 from homeassistant.const import (
     ENERGY_KILO_WATT_HOUR,
+    LENGTH_METERS,
     MASS_KILOGRAMS,
     POWER_WATT,
     TEMP_CELSIUS,
@@ -26,12 +27,12 @@ SENSORS = {
     "V_GUST": [None, "mdi:weather-windy"],
     "V_DIRECTION": [UNIT_DEGREE, "mdi:compass"],
     "V_WEIGHT": [MASS_KILOGRAMS, "mdi:weight-kilogram"],
-    "V_DISTANCE": ["m", "mdi:ruler"],
+    "V_DISTANCE": [LENGTH_METERS, "mdi:ruler"],
     "V_IMPEDANCE": ["ohm", None],
     "V_WATT": [POWER_WATT, None],
     "V_KWH": [ENERGY_KILO_WATT_HOUR, None],
     "V_LIGHT_LEVEL": [UNIT_PERCENTAGE, "mdi:white-balance-sunny"],
-    "V_FLOW": ["m", "mdi:gauge"],
+    "V_FLOW": [LENGTH_METERS, "mdi:gauge"],
     "V_VOLUME": ["m³", None],
     "V_LEVEL": {
         "S_SOUND": ["dB", "mdi:volume-high"],
diff --git a/homeassistant/components/proximity/__init__.py b/homeassistant/components/proximity/__init__.py
index c82818bca1a..4b6ff477053 100644
--- a/homeassistant/components/proximity/__init__.py
+++ b/homeassistant/components/proximity/__init__.py
@@ -8,6 +8,7 @@ from homeassistant.const import (
     CONF_UNIT_OF_MEASUREMENT,
     CONF_ZONE,
     LENGTH_KILOMETERS,
+    LENGTH_METERS,
 )
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entity import Entity
@@ -33,7 +34,7 @@ DEFAULT_PROXIMITY_ZONE = "home"
 DEFAULT_TOLERANCE = 1
 DOMAIN = "proximity"
 
-UNITS = [LENGTH_KILOMETERS, "m", "mi", "ft"]
+UNITS = [LENGTH_KILOMETERS, LENGTH_METERS, "mi", "ft"]
 
 ZONE_SCHEMA = vol.Schema(
     {
@@ -210,7 +211,7 @@ class Proximity(Entity):
 
             # Add the device and distance to a dictionary.
             distances_to_zone[device] = round(
-                convert(dist_to_zone, "m", self.unit_of_measurement), 1
+                convert(dist_to_zone, LENGTH_METERS, self.unit_of_measurement), 1
             )
 
         # Loop through each of the distances collected and work out the
diff --git a/homeassistant/components/zamg/sensor.py b/homeassistant/components/zamg/sensor.py
index 6580ab0917f..a9f43f0fb21 100644
--- a/homeassistant/components/zamg/sensor.py
+++ b/homeassistant/components/zamg/sensor.py
@@ -17,6 +17,7 @@ from homeassistant.const import (
     CONF_LONGITUDE,
     CONF_MONITORED_CONDITIONS,
     CONF_NAME,
+    LENGTH_METERS,
     SPEED_KILOMETERS_PER_HOUR,
     TEMP_CELSIUS,
     UNIT_DEGREE,
@@ -64,7 +65,12 @@ SENSOR_TYPES = {
     # The following probably not useful for general consumption,
     # but we need them to fill in internal attributes
     "station_name": ("Station Name", None, "Name", str),
-    "station_elevation": ("Station Elevation", "m", "Höhe m", int),
+    "station_elevation": (
+        "Station Elevation",
+        LENGTH_METERS,
+        f"Höhe {LENGTH_METERS}",
+        int,
+    ),
     "update_date": ("Update Date", None, "Datum", str),
     "update_time": ("Update Time", None, "Zeit", str),
 }
diff --git a/homeassistant/core.py b/homeassistant/core.py
index 8ad8c24bd53..b3f4a68e37f 100644
--- a/homeassistant/core.py
+++ b/homeassistant/core.py
@@ -56,6 +56,7 @@ from homeassistant.const import (
     EVENT_STATE_CHANGED,
     EVENT_TIME_CHANGED,
     EVENT_TIMER_OUT_OF_SYNC,
+    LENGTH_METERS,
     MATCH_ALL,
     __version__,
 )
@@ -1324,7 +1325,7 @@ class Config:
         Async friendly.
         """
         return self.units.length(
-            location.distance(self.latitude, self.longitude, lat, lon), "m"
+            location.distance(self.latitude, self.longitude, lat, lon), LENGTH_METERS
         )
 
     def path(self, *path: str) -> str:
diff --git a/homeassistant/helpers/template.py b/homeassistant/helpers/template.py
index 8c7b103f834..b6c59604b74 100644
--- a/homeassistant/helpers/template.py
+++ b/homeassistant/helpers/template.py
@@ -19,6 +19,7 @@ from homeassistant.const import (
     ATTR_LATITUDE,
     ATTR_LONGITUDE,
     ATTR_UNIT_OF_MEASUREMENT,
+    LENGTH_METERS,
     MATCH_ALL,
     STATE_UNKNOWN,
 )
@@ -638,7 +639,7 @@ def distance(hass, *args):
         return hass.config.distance(*locations[0])
 
     return hass.config.units.length(
-        loc_util.distance(*locations[0] + locations[1]), "m"
+        loc_util.distance(*locations[0] + locations[1]), LENGTH_METERS
     )