diff --git a/homeassistant/components/opentherm_gw/__init__.py b/homeassistant/components/opentherm_gw/__init__.py
index 7e91f78f74c..b20d97dadce 100644
--- a/homeassistant/components/opentherm_gw/__init__.py
+++ b/homeassistant/components/opentherm_gw/__init__.py
@@ -30,6 +30,7 @@ from .const import (
     ATTR_GW_ID,
     ATTR_MODE,
     ATTR_LEVEL,
+    ATTR_DHW_OVRD,
     CONF_CLIMATE,
     CONF_FLOOR_TEMP,
     CONF_PRECISION,
@@ -38,6 +39,7 @@ from .const import (
     SERVICE_RESET_GATEWAY,
     SERVICE_SET_CLOCK,
     SERVICE_SET_CONTROL_SETPOINT,
+    SERVICE_SET_HOT_WATER_OVRD,
     SERVICE_SET_GPIO_MODE,
     SERVICE_SET_LED_MODE,
     SERVICE_SET_MAX_MOD,
@@ -123,6 +125,16 @@ def register_services(hass):
             ),
         }
     )
+    service_set_hot_water_ovrd_schema = vol.Schema(
+        {
+            vol.Required(ATTR_GW_ID): vol.All(
+                cv.string, vol.In(hass.data[DATA_OPENTHERM_GW][DATA_GATEWAYS])
+            ),
+            vol.Required(ATTR_DHW_OVRD): vol.Any(
+                vol.Equal("A"), vol.All(vol.Coerce(int), vol.Range(min=0, max=1))
+            ),
+        }
+    )
     service_set_gpio_mode_schema = vol.Schema(
         vol.Any(
             vol.Schema(
@@ -216,6 +228,21 @@ def register_services(hass):
         service_set_control_setpoint_schema,
     )
 
+    async def set_dhw_ovrd(call):
+        """Set the domestic hot water override on the OpenTherm Gateway."""
+        gw_dev = hass.data[DATA_OPENTHERM_GW][DATA_GATEWAYS][call.data[ATTR_GW_ID]]
+        gw_var = gw_vars.OTGW_DHW_OVRD
+        value = await gw_dev.gateway.set_hot_water_ovrd(call.data[ATTR_DHW_OVRD])
+        gw_dev.status.update({gw_var: value})
+        async_dispatcher_send(hass, gw_dev.update_signal, gw_dev.status)
+
+    hass.services.async_register(
+        DOMAIN,
+        SERVICE_SET_HOT_WATER_OVRD,
+        set_dhw_ovrd,
+        service_set_hot_water_ovrd_schema,
+    )
+
     async def set_device_clock(call):
         """Set the clock on the OpenTherm Gateway."""
         gw_dev = hass.data[DATA_OPENTHERM_GW][DATA_GATEWAYS][call.data[ATTR_GW_ID]]
diff --git a/homeassistant/components/opentherm_gw/const.py b/homeassistant/components/opentherm_gw/const.py
index 5b0411a2c72..77b0bf9b313 100644
--- a/homeassistant/components/opentherm_gw/const.py
+++ b/homeassistant/components/opentherm_gw/const.py
@@ -6,6 +6,7 @@ from homeassistant.const import DEVICE_CLASS_TEMPERATURE, TEMP_CELSIUS
 ATTR_GW_ID = "gateway_id"
 ATTR_MODE = "mode"
 ATTR_LEVEL = "level"
+ATTR_DHW_OVRD = "dhw_override"
 
 CONF_CLIMATE = "climate"
 CONF_FLOOR_TEMP = "floor_temperature"
@@ -21,6 +22,7 @@ DEVICE_CLASS_PROBLEM = "problem"
 SERVICE_RESET_GATEWAY = "reset_gateway"
 SERVICE_SET_CLOCK = "set_clock"
 SERVICE_SET_CONTROL_SETPOINT = "set_control_setpoint"
+SERVICE_SET_HOT_WATER_OVRD = "set_hot_water_ovrd"
 SERVICE_SET_GPIO_MODE = "set_gpio_mode"
 SERVICE_SET_LED_MODE = "set_led_mode"
 SERVICE_SET_MAX_MOD = "set_max_modulation"
diff --git a/homeassistant/components/opentherm_gw/services.yaml b/homeassistant/components/opentherm_gw/services.yaml
index d8fe2c7e406..4e9e727ef5a 100644
--- a/homeassistant/components/opentherm_gw/services.yaml
+++ b/homeassistant/components/opentherm_gw/services.yaml
@@ -35,6 +35,23 @@ set_control_setpoint:
         A value of 0 disables the central heating setpoint override.
       example: '37.5'
 
+set_hot_water_ovrd:
+  description: >
+    Set the domestic hot water enable option on the gateway.
+  fields:
+    gateway_id:
+      description: The gateway_id of the OpenTherm Gateway.
+      example: 'opentherm_gateway'
+    dhw_override:
+      description: >
+        Control the domestic hot water enable option. If the boiler has
+        been configured to let the room unit control when to keep a
+        small amount of water preheated, this command can influence
+        that.
+        Value should be 0 or 1 to enable the override in off or on
+        state, or "A" to disable the override.
+      example: '1'
+
 set_gpio_mode:
   description: Change the function of the GPIO pins of the gateway.
   fields: