diff --git a/homeassistant/components/automation/__init__.py b/homeassistant/components/automation/__init__.py
index 862a664976b..4555a336cc3 100644
--- a/homeassistant/components/automation/__init__.py
+++ b/homeassistant/components/automation/__init__.py
@@ -517,14 +517,14 @@ class AutomationEntity(ToggleEntity, RestoreEntity):
         if self._trigger_variables:
             try:
                 variables = self._trigger_variables.async_render(
-                    cast(HomeAssistant, self.hass), None, limited=True
+                    self.hass, None, limited=True
                 )
             except template.TemplateError as err:
                 self._logger.error("Error rendering trigger variables: %s", err)
                 return None
 
         return await async_initialize_triggers(
-            cast(HomeAssistant, self.hass),
+            self.hass,
             self._trigger_config,
             self.async_trigger,
             DOMAIN,
diff --git a/homeassistant/components/bond/entity.py b/homeassistant/components/bond/entity.py
index cd120d79d56..b56c87f692f 100644
--- a/homeassistant/components/bond/entity.py
+++ b/homeassistant/components/bond/entity.py
@@ -158,7 +158,6 @@ class BondEntity(Entity):
         await super().async_added_to_hass()
         self._update_lock = Lock()
         self._bpup_subs.subscribe(self._device_id, self._async_bpup_callback)
-        assert self.hass is not None
         self.async_on_remove(
             async_track_time_interval(
                 self.hass, self._async_update_if_bpup_not_alive, _FALLBACK_SCAN_INTERVAL
diff --git a/homeassistant/components/climacell/config_flow.py b/homeassistant/components/climacell/config_flow.py
index 09e02f3f559..7048e4e5c2a 100644
--- a/homeassistant/components/climacell/config_flow.py
+++ b/homeassistant/components/climacell/config_flow.py
@@ -110,7 +110,6 @@ class ClimaCellConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
         self, user_input: Dict[str, Any] = None
     ) -> Dict[str, Any]:
         """Handle the initial step."""
-        assert self.hass
         errors = {}
         if user_input is not None:
             await self.async_set_unique_id(
diff --git a/homeassistant/components/group/__init__.py b/homeassistant/components/group/__init__.py
index f185601ce87..1ce0b3e71d7 100644
--- a/homeassistant/components/group/__init__.py
+++ b/homeassistant/components/group/__init__.py
@@ -395,7 +395,6 @@ class GroupEntity(Entity):
 
     async def async_added_to_hass(self) -> None:
         """Register listeners."""
-        assert self.hass is not None
 
         async def _update_at_start(_):
             await self.async_update()
@@ -405,8 +404,6 @@ class GroupEntity(Entity):
 
     async def async_defer_or_update_ha_state(self) -> None:
         """Only update once at start."""
-        assert self.hass is not None
-
         if self.hass.state != CoreState.running:
             return
 
diff --git a/homeassistant/components/group/cover.py b/homeassistant/components/group/cover.py
index da842ee9f00..c19e81778a0 100644
--- a/homeassistant/components/group/cover.py
+++ b/homeassistant/components/group/cover.py
@@ -155,7 +155,6 @@ class CoverGroup(GroupEntity, CoverEntity):
             await self.async_update_supported_features(
                 entity_id, new_state, update_state=False
             )
-        assert self.hass is not None
         self.async_on_remove(
             async_track_state_change_event(
                 self.hass, self._entities, self._update_supported_features_event
diff --git a/homeassistant/components/group/light.py b/homeassistant/components/group/light.py
index 482bdbafdab..cebc697efae 100644
--- a/homeassistant/components/group/light.py
+++ b/homeassistant/components/group/light.py
@@ -103,7 +103,6 @@ class LightGroup(GroupEntity, light.LightEntity):
             self.async_set_context(event.context)
             await self.async_defer_or_update_ha_state()
 
-        assert self.hass
         self.async_on_remove(
             async_track_state_change_event(
                 self.hass, self._entity_ids, async_state_changed_listener
diff --git a/homeassistant/components/huawei_lte/__init__.py b/homeassistant/components/huawei_lte/__init__.py
index 341f9c0a118..2d33d1a1822 100644
--- a/homeassistant/components/huawei_lte/__init__.py
+++ b/homeassistant/components/huawei_lte/__init__.py
@@ -636,7 +636,6 @@ class HuaweiLteBaseEntity(Entity):
 
     async def async_added_to_hass(self) -> None:
         """Connect to update signals."""
-        assert self.hass is not None
         self._unsub_handlers.append(
             async_dispatcher_connect(self.hass, UPDATE_SIGNAL, self._async_maybe_update)
         )
diff --git a/homeassistant/components/hyperion/light.py b/homeassistant/components/hyperion/light.py
index 838b69cd52b..89f70c8f24d 100644
--- a/homeassistant/components/hyperion/light.py
+++ b/homeassistant/components/hyperion/light.py
@@ -397,7 +397,6 @@ class HyperionBaseLight(LightEntity):
 
     async def async_added_to_hass(self) -> None:
         """Register callbacks when entity added to hass."""
-        assert self.hass
         self.async_on_remove(
             async_dispatcher_connect(
                 self.hass,
diff --git a/homeassistant/components/hyperion/switch.py b/homeassistant/components/hyperion/switch.py
index e2da80e5093..f6317a8f396 100644
--- a/homeassistant/components/hyperion/switch.py
+++ b/homeassistant/components/hyperion/switch.py
@@ -193,7 +193,6 @@ class HyperionComponentSwitch(SwitchEntity):
 
     async def async_added_to_hass(self) -> None:
         """Register callbacks when entity added to hass."""
-        assert self.hass
         self.async_on_remove(
             async_dispatcher_connect(
                 self.hass,
diff --git a/homeassistant/components/notify/__init__.py b/homeassistant/components/notify/__init__.py
index 7be66dc3c59..5e1493a68eb 100644
--- a/homeassistant/components/notify/__init__.py
+++ b/homeassistant/components/notify/__init__.py
@@ -2,7 +2,7 @@
 import asyncio
 from functools import partial
 import logging
-from typing import Any, Dict, Optional, cast
+from typing import Any, Dict, cast
 
 import voluptuous as vol
 
@@ -114,7 +114,11 @@ def _async_integration_has_notify_services(
 class BaseNotificationService:
     """An abstract class for notification services."""
 
-    hass: Optional[HomeAssistantType] = None
+    # While not purely typed, it makes typehinting more useful for us
+    # and removes the need for constant None checks or asserts.
+    # Ignore types: https://github.com/PyCQA/pylint/issues/3167
+    hass: HomeAssistantType = None  # type: ignore
+
     # Name => target
     registered_targets: Dict[str, str]
 
@@ -130,7 +134,9 @@ class BaseNotificationService:
 
         kwargs can contain ATTR_TITLE to specify a title.
         """
-        await self.hass.async_add_executor_job(partial(self.send_message, message, **kwargs))  # type: ignore
+        await self.hass.async_add_executor_job(
+            partial(self.send_message, message, **kwargs)
+        )
 
     async def _async_notify_message_service(self, service: ServiceCall) -> None:
         """Handle sending notification message service calls."""
@@ -175,8 +181,6 @@ class BaseNotificationService:
 
     async def async_register_services(self) -> None:
         """Create or update the notify services."""
-        assert self.hass
-
         if hasattr(self, "targets"):
             stale_targets = set(self.registered_targets)
 
@@ -232,8 +236,6 @@ class BaseNotificationService:
 
     async def async_unregister_services(self) -> None:
         """Unregister the notify services."""
-        assert self.hass
-
         if self.registered_targets:
             remove_targets = set(self.registered_targets)
             for remove_target_name in remove_targets:
diff --git a/homeassistant/components/number/__init__.py b/homeassistant/components/number/__init__.py
index 31a0bcd7762..933b07e4f58 100644
--- a/homeassistant/components/number/__init__.py
+++ b/homeassistant/components/number/__init__.py
@@ -110,5 +110,4 @@ class NumberEntity(Entity):
 
     async def async_set_value(self, value: float) -> None:
         """Set new value."""
-        assert self.hass is not None
         await self.hass.async_add_executor_job(self.set_value, value)
diff --git a/homeassistant/components/remote/__init__.py b/homeassistant/components/remote/__init__.py
index 720f7c5ff16..12b81402d61 100644
--- a/homeassistant/components/remote/__init__.py
+++ b/homeassistant/components/remote/__init__.py
@@ -173,7 +173,6 @@ class RemoteEntity(ToggleEntity):
 
     async def async_send_command(self, command: Iterable[str], **kwargs: Any) -> None:
         """Send commands to a device."""
-        assert self.hass is not None
         await self.hass.async_add_executor_job(
             ft.partial(self.send_command, command, **kwargs)
         )
@@ -184,7 +183,6 @@ class RemoteEntity(ToggleEntity):
 
     async def async_learn_command(self, **kwargs: Any) -> None:
         """Learn a command from a device."""
-        assert self.hass is not None
         await self.hass.async_add_executor_job(ft.partial(self.learn_command, **kwargs))
 
     def delete_command(self, **kwargs: Any) -> None:
@@ -193,7 +191,6 @@ class RemoteEntity(ToggleEntity):
 
     async def async_delete_command(self, **kwargs: Any) -> None:
         """Delete commands from the database."""
-        assert self.hass is not None
         await self.hass.async_add_executor_job(
             ft.partial(self.delete_command, **kwargs)
         )
diff --git a/homeassistant/components/scene/__init__.py b/homeassistant/components/scene/__init__.py
index 245d21770ee..4bc63d585be 100644
--- a/homeassistant/components/scene/__init__.py
+++ b/homeassistant/components/scene/__init__.py
@@ -104,7 +104,6 @@ class Scene(Entity):
 
     async def async_activate(self, **kwargs: Any) -> None:
         """Activate scene. Try to get entities into requested state."""
-        assert self.hass
         task = self.hass.async_add_job(ft.partial(self.activate, **kwargs))
         if task:
             await task
diff --git a/homeassistant/components/switch/light.py b/homeassistant/components/switch/light.py
index 2650bd61bfb..fc8638162e7 100644
--- a/homeassistant/components/switch/light.py
+++ b/homeassistant/components/switch/light.py
@@ -120,13 +120,11 @@ class LightSwitch(LightEntity):
 
     async def async_added_to_hass(self) -> None:
         """Register callbacks."""
-        assert self.hass is not None
         self._switch_state = self.hass.states.get(self._switch_entity_id)
 
         @callback
         def async_state_changed_listener(*_: Any) -> None:
             """Handle child updates."""
-            assert self.hass is not None
             self._switch_state = self.hass.states.get(self._switch_entity_id)
             self.async_write_ha_state()
 
diff --git a/homeassistant/components/zwave_js/climate.py b/homeassistant/components/zwave_js/climate.py
index 9276ec2ed0b..3f6b26f536f 100644
--- a/homeassistant/components/zwave_js/climate.py
+++ b/homeassistant/components/zwave_js/climate.py
@@ -373,7 +373,6 @@ class ZWaveClimate(ZWaveBaseEntity, ClimateEntity):
 
     async def async_set_temperature(self, **kwargs: Any) -> None:
         """Set new target temperature."""
-        assert self.hass
         hvac_mode: Optional[str] = kwargs.get(ATTR_HVAC_MODE)
 
         if hvac_mode is not None:
diff --git a/homeassistant/components/zwave_js/config_flow.py b/homeassistant/components/zwave_js/config_flow.py
index 4929f7e7869..8ba2909cf20 100644
--- a/homeassistant/components/zwave_js/config_flow.py
+++ b/homeassistant/components/zwave_js/config_flow.py
@@ -89,7 +89,6 @@ class ConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
         self, user_input: Optional[Dict[str, Any]] = None
     ) -> Dict[str, Any]:
         """Handle the initial step."""
-        assert self.hass  # typing
         if is_hassio(self.hass):  # type: ignore  # no-untyped-call
             return await self.async_step_on_supervisor()
 
@@ -266,7 +265,6 @@ class ConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
         self, user_input: Optional[Dict[str, Any]] = None
     ) -> Dict[str, Any]:
         """Start Z-Wave JS add-on."""
-        assert self.hass
         if not self.start_task:
             self.start_task = self.hass.async_create_task(self._async_start_addon())
             return self.async_show_progress(
@@ -289,7 +287,6 @@ class ConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
 
     async def _async_start_addon(self) -> None:
         """Start the Z-Wave JS add-on."""
-        assert self.hass
         addon_manager: AddonManager = get_addon_manager(self.hass)
         try:
             await addon_manager.async_schedule_start_addon()
@@ -327,7 +324,6 @@ class ConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
         Get add-on discovery info and server version info.
         Set unique id and abort if already configured.
         """
-        assert self.hass
         if not self.ws_address:
             discovery_info = await self._async_get_addon_discovery_info()
             self.ws_address = f"ws://{discovery_info['host']}:{discovery_info['port']}"
diff --git a/homeassistant/components/zwave_js/entity.py b/homeassistant/components/zwave_js/entity.py
index 7620323d940..34b5940bfea 100644
--- a/homeassistant/components/zwave_js/entity.py
+++ b/homeassistant/components/zwave_js/entity.py
@@ -46,7 +46,6 @@ class ZWaveBaseEntity(Entity):
 
     async def async_poll_value(self, refresh_all_values: bool) -> None:
         """Poll a value."""
-        assert self.hass
         if not refresh_all_values:
             self.hass.async_create_task(
                 self.info.node.async_poll_value(self.info.primary_value)
@@ -75,7 +74,6 @@ class ZWaveBaseEntity(Entity):
 
     async def async_added_to_hass(self) -> None:
         """Call when entity is added."""
-        assert self.hass  # typing
         # Add value_changed callbacks.
         self.async_on_remove(
             self.info.node.on(EVENT_VALUE_UPDATED, self._value_changed)
diff --git a/homeassistant/helpers/config_entry_flow.py b/homeassistant/helpers/config_entry_flow.py
index 69248186b53..fea188ca336 100644
--- a/homeassistant/helpers/config_entry_flow.py
+++ b/homeassistant/helpers/config_entry_flow.py
@@ -59,7 +59,6 @@ class DiscoveryFlowHandler(config_entries.ConfigFlow):
                 return self.async_abort(reason="no_devices_found")
 
             # Cancel the discovered one.
-            assert self.hass is not None
             for flow in in_progress:
                 self.hass.config_entries.flow.async_abort(flow["flow_id"])
 
@@ -91,7 +90,6 @@ class DiscoveryFlowHandler(config_entries.ConfigFlow):
             return self.async_abort(reason="single_instance_allowed")
 
         # Cancel other flows.
-        assert self.hass is not None
         in_progress = self._async_in_progress()
         for flow in in_progress:
             self.hass.config_entries.flow.async_abort(flow["flow_id"])
@@ -144,7 +142,6 @@ class WebhookFlowHandler(config_entries.ConfigFlow):
         if user_input is None:
             return self.async_show_form(step_id="user")
 
-        assert self.hass is not None
         webhook_id = self.hass.components.webhook.async_generate_id()
 
         if (
diff --git a/homeassistant/helpers/config_entry_oauth2_flow.py b/homeassistant/helpers/config_entry_oauth2_flow.py
index 653d07a333e..691715452ea 100644
--- a/homeassistant/helpers/config_entry_oauth2_flow.py
+++ b/homeassistant/helpers/config_entry_oauth2_flow.py
@@ -234,7 +234,6 @@ class AbstractOAuth2FlowHandler(config_entries.ConfigFlow, metaclass=ABCMeta):
         self, user_input: Optional[dict] = None
     ) -> dict:
         """Handle a flow start."""
-        assert self.hass
         implementations = await async_get_implementations(self.hass, self.DOMAIN)
 
         if user_input is not None:
@@ -318,7 +317,6 @@ class AbstractOAuth2FlowHandler(config_entries.ConfigFlow, metaclass=ABCMeta):
         """Handle a flow initialized by discovery."""
         await self.async_set_unique_id(self.DOMAIN)
 
-        assert self.hass is not None
         if self.hass.config_entries.async_entries(self.DOMAIN):
             return self.async_abort(reason="already_configured")
 
diff --git a/homeassistant/helpers/entity.py b/homeassistant/helpers/entity.py
index 7afe1b2ad25..791b1e251cd 100644
--- a/homeassistant/helpers/entity.py
+++ b/homeassistant/helpers/entity.py
@@ -89,10 +89,13 @@ class Entity(ABC):
     # SAFE TO OVERWRITE
     # The properties and methods here are safe to overwrite when inheriting
     # this class. These may be used to customize the behavior of the entity.
-    entity_id = None  # type: str
+    entity_id: str = None  # type: ignore
 
     # Owning hass instance. Will be set by EntityPlatform
-    hass: Optional[HomeAssistant] = None
+    # While not purely typed, it makes typehinting more useful for us
+    # and removes the need for constant None checks or asserts.
+    # Ignore types: https://github.com/PyCQA/pylint/issues/3167
+    hass: HomeAssistant = None  # type: ignore
 
     # Owning platform instance. Will be set by EntityPlatform
     platform: Optional[EntityPlatform] = None
@@ -391,7 +394,6 @@ class Entity(ABC):
             )
 
         # Overwrite properties that have been set in the config file.
-        assert self.hass is not None
         if DATA_CUSTOMIZE in self.hass.data:
             attr.update(self.hass.data[DATA_CUSTOMIZE].get(self.entity_id))
 
@@ -432,7 +434,6 @@ class Entity(ABC):
         If state is changed more than once before the ha state change task has
         been executed, the intermediate state transitions will be missed.
         """
-        assert self.hass is not None
         self.hass.add_job(self.async_update_ha_state(force_refresh))  # type: ignore
 
     @callback
@@ -448,7 +449,6 @@ class Entity(ABC):
         been executed, the intermediate state transitions will be missed.
         """
         if force_refresh:
-            assert self.hass is not None
             self.hass.async_create_task(self.async_update_ha_state(force_refresh))
         else:
             self.async_write_ha_state()
@@ -532,7 +532,7 @@ class Entity(ABC):
     @callback
     def add_to_platform_abort(self) -> None:
         """Abort adding an entity to a platform."""
-        self.hass = None
+        self.hass = None  # type: ignore
         self.platform = None
         self.parallel_updates = None
         self._added = False
@@ -553,8 +553,6 @@ class Entity(ABC):
         If the entity doesn't have a non disabled entry in the entity registry,
         or if force_remove=True, its state will be removed.
         """
-        assert self.hass is not None
-
         if self.platform and not self._added:
             raise HomeAssistantError(
                 f"Entity {self.entity_id} async_remove called twice"
@@ -597,8 +595,6 @@ class Entity(ABC):
 
         Not to be extended by integrations.
         """
-        assert self.hass is not None
-
         if self.platform:
             info = {"domain": self.platform.platform_name}
 
@@ -628,7 +624,6 @@ class Entity(ABC):
         Not to be extended by integrations.
         """
         if self.platform:
-            assert self.hass is not None
             self.hass.data[DATA_ENTITY_SOURCE].pop(self.entity_id)
 
     async def _async_registry_updated(self, event: Event) -> None:
@@ -642,7 +637,6 @@ class Entity(ABC):
         if data["action"] != "update":
             return
 
-        assert self.hass is not None
         ent_reg = await self.hass.helpers.entity_registry.async_get_registry()
         old = self.registry_entry
         self.registry_entry = ent_reg.async_get(data["entity_id"])
@@ -717,7 +711,6 @@ class ToggleEntity(Entity):
 
     async def async_turn_on(self, **kwargs: Any) -> None:
         """Turn the entity on."""
-        assert self.hass is not None
         await self.hass.async_add_executor_job(ft.partial(self.turn_on, **kwargs))
 
     def turn_off(self, **kwargs: Any) -> None:
@@ -726,7 +719,6 @@ class ToggleEntity(Entity):
 
     async def async_turn_off(self, **kwargs: Any) -> None:
         """Turn the entity off."""
-        assert self.hass is not None
         await self.hass.async_add_executor_job(ft.partial(self.turn_off, **kwargs))
 
     def toggle(self, **kwargs: Any) -> None:
diff --git a/homeassistant/helpers/restore_state.py b/homeassistant/helpers/restore_state.py
index 4f738887ce3..51ebc6fa774 100644
--- a/homeassistant/helpers/restore_state.py
+++ b/homeassistant/helpers/restore_state.py
@@ -235,7 +235,6 @@ class RestoreEntity(Entity):
 
     async def async_internal_added_to_hass(self) -> None:
         """Register this entity as a restorable entity."""
-        assert self.hass is not None
         _, data = await asyncio.gather(
             super().async_internal_added_to_hass(),
             RestoreStateData.async_get_instance(self.hass),
@@ -244,7 +243,6 @@ class RestoreEntity(Entity):
 
     async def async_internal_will_remove_from_hass(self) -> None:
         """Run when entity will be removed from hass."""
-        assert self.hass is not None
         _, data = await asyncio.gather(
             super().async_internal_will_remove_from_hass(),
             RestoreStateData.async_get_instance(self.hass),
@@ -255,7 +253,7 @@ class RestoreEntity(Entity):
         """Get the entity state from the previous run."""
         if self.hass is None or self.entity_id is None:
             # Return None if this entity isn't added to hass yet
-            _LOGGER.warning("Cannot get last state. Entity not added to hass")
+            _LOGGER.warning("Cannot get last state. Entity not added to hass")  # type: ignore[unreachable]
             return None
         data = await RestoreStateData.async_get_instance(self.hass)
         if self.entity_id not in data.last_states:
diff --git a/homeassistant/helpers/template.py b/homeassistant/helpers/template.py
index 8b3f6ec6e59..7f768354035 100644
--- a/homeassistant/helpers/template.py
+++ b/homeassistant/helpers/template.py
@@ -425,8 +425,6 @@ class Template:
 
         This method must be run in the event loop.
         """
-        assert self.hass
-
         if self.is_static:
             return False