diff --git a/homeassistant/components/rainmachine/__init__.py b/homeassistant/components/rainmachine/__init__.py
index 45070e40e58..4844a9e68c8 100644
--- a/homeassistant/components/rainmachine/__init__.py
+++ b/homeassistant/components/rainmachine/__init__.py
@@ -24,7 +24,6 @@ from homeassistant.helpers.entity import Entity
 from homeassistant.helpers.event import async_track_time_interval
 from homeassistant.helpers.service import verify_domain_control
 
-from .config_flow import configured_instances
 from .const import (
     DATA_CLIENT,
     DATA_PROGRAMS,
@@ -118,9 +117,6 @@ async def async_setup(hass, config):
     conf = config[DOMAIN]
 
     for controller in conf[CONF_CONTROLLERS]:
-        if controller[CONF_IP_ADDRESS] in configured_instances(hass):
-            continue
-
         hass.async_create_task(
             hass.config_entries.flow.async_init(
                 DOMAIN, context={"source": SOURCE_IMPORT}, data=controller
@@ -132,6 +128,11 @@ async def async_setup(hass, config):
 
 async def async_setup_entry(hass, config_entry):
     """Set up RainMachine as config entry."""
+    if not config_entry.unique_id:
+        hass.config_entries.async_update_entry(
+            config_entry, unique_id=config_entry.data[CONF_IP_ADDRESS]
+        )
+
     _verify_domain_control = verify_domain_control(hass, DOMAIN)
 
     websession = aiohttp_client.async_get_clientsession(hass)
diff --git a/homeassistant/components/rainmachine/config_flow.py b/homeassistant/components/rainmachine/config_flow.py
index 3fb731c5856..ffa46cc2c15 100644
--- a/homeassistant/components/rainmachine/config_flow.py
+++ b/homeassistant/components/rainmachine/config_flow.py
@@ -5,19 +5,9 @@ import voluptuous as vol
 
 from homeassistant import config_entries
 from homeassistant.const import CONF_IP_ADDRESS, CONF_PASSWORD, CONF_PORT
-from homeassistant.core import callback
 from homeassistant.helpers import aiohttp_client
 
-from .const import DEFAULT_PORT, DOMAIN
-
-
-@callback
-def configured_instances(hass):
-    """Return a set of configured RainMachine instances."""
-    return set(
-        entry.data[CONF_IP_ADDRESS]
-        for entry in hass.config_entries.async_entries(DOMAIN)
-    )
+from .const import DEFAULT_PORT, DOMAIN  # pylint: disable=unused-import
 
 
 class RainMachineFlowHandler(config_entries.ConfigFlow, domain=DOMAIN):
diff --git a/tests/components/rainmachine/test_config_flow.py b/tests/components/rainmachine/test_config_flow.py
index 379532c8f50..38dafdda986 100644
--- a/tests/components/rainmachine/test_config_flow.py
+++ b/tests/components/rainmachine/test_config_flow.py
@@ -29,8 +29,6 @@ async def test_duplicate_error(hass):
     MockConfigEntry(domain=DOMAIN, unique_id="192.168.1.100", data=conf).add_to_hass(
         hass
     )
-    flow = config_flow.RainMachineFlowHandler()
-    flow.hass = hass
 
     result = await hass.config_entries.flow.async_init(
         DOMAIN, context={"source": SOURCE_USER}, data=conf
@@ -39,22 +37,6 @@ async def test_duplicate_error(hass):
     assert result["reason"] == "already_configured"
 
 
-async def test_get_configured_instances(hass):
-    """Test retrieving all configured instances."""
-    conf = {
-        CONF_IP_ADDRESS: "192.168.1.100",
-        CONF_PASSWORD: "password",
-        CONF_PORT: 8080,
-        CONF_SSL: True,
-    }
-
-    MockConfigEntry(domain=DOMAIN, unique_id="192.168.1.100", data=conf).add_to_hass(
-        hass
-    )
-
-    assert len(config_flow.configured_instances(hass)) == 1
-
-
 async def test_invalid_password(hass):
     """Test that an invalid password throws an error."""
     conf = {