diff --git a/modules/programs/waybar.nix b/modules/programs/waybar.nix
index 7234278f..5472a0ef 100644
--- a/modules/programs/waybar.nix
+++ b/modules/programs/waybar.nix
@@ -2,8 +2,8 @@
 
 let
   inherit (lib)
-    any attrByPath attrNames concatMap concatMapStringsSep elem filter
-    filterAttrs flip foldl' hasPrefix mergeAttrs optionalAttrs removePrefix
+    any attrByPath attrNames concatMap concatMapStringsSep elem elemAt filter
+    filterAttrs flip foldl' hasPrefix head length mergeAttrs optionalAttrs
     stringLength subtractLists types unique;
   inherit (lib.options) literalExample mkEnableOption mkOption;
   inherit (lib.modules) mkIf mkMerge;
@@ -40,13 +40,19 @@ let
     "bluetooth"
   ];
 
-  # Allow specifying a CSS class after the default module name
+  # Allow specifying a CSS id after the default module name
   isValidDefaultModuleName = x:
-    any (name: hasPrefix name x && hasPrefix "#" (removePrefix name x))
+    any (name:
+      let
+        res = builtins.split name x;
+        # if exact match of default module name
+      in if res == [ "" [ ] ] || res == [ "" [ ] "" ] then
+        true
+      else
+        head res == "" && length res >= 3 && hasPrefix "#" (elemAt res 2))
     defaultModuleNames;
 
-  isValidCustomModuleName = x:
-    hasPrefix "custom/" x && stringLength x > 7 || isValidDefaultModuleName x;
+  isValidCustomModuleName = x: hasPrefix "custom/" x && stringLength x > 7;
 
   margins = let
     mkMargin = name: {
@@ -321,12 +327,14 @@ in {
           # Modules declared in `modules` but not referenced in `modules-{left,center,right}`
           unreferencedModules = subtractLists allModules declaredModules;
           # Modules listed in modules-{left,center,right} that are not default modules
-          nonDefaultModules = subtractLists defaultModuleNames allModules;
+          nonDefaultModules =
+            filter (x: !isValidDefaultModuleName x) allModules;
           # Modules referenced in `modules-{left,center,right}` but not declared in `modules`
           undefinedModules = subtractLists declaredModules nonDefaultModules;
           # Check for invalid module names
-          invalidModuleNames =
-            filter (m: !isValidCustomModuleName m) declaredModules;
+          invalidModuleNames = filter
+            (m: !isValidCustomModuleName m && !isValidDefaultModuleName m)
+            declaredModules;
         in {
           # The Waybar bar configuration (since config.settings is a list)
           inherit settings;
diff --git a/tests/modules/programs/waybar/broken-settings.nix b/tests/modules/programs/waybar/broken-settings.nix
deleted file mode 100644
index d0e13150..00000000
--- a/tests/modules/programs/waybar/broken-settings.nix
+++ /dev/null
@@ -1,84 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-with lib;
-
-let
-  package = pkgs.writeScriptBin "dummy-waybar" "" // { outPath = "@waybar@"; };
-  expected = pkgs.writeText "expected-json" ''
-    [
-      {
-        "height": 26,
-        "layer": "top",
-        "modules-center": [
-          "sway/window"
-        ],
-        "modules-left": [
-          "sway/workspaces",
-          "sway/mode"
-        ],
-        "modules-right": [
-          "idle_inhibitor",
-          "pulseaudio",
-          "network",
-          "cpu",
-          "memory",
-          "backlight",
-          "tray",
-          "clock"
-        ],
-        "output": [
-          "DP-1",
-          "eDP-1",
-          "HEADLESS-1"
-        ],
-        "position": "top",
-        "sway/workspaces": {
-          "all-outputs": true
-        }
-      }
-    ]
-  '';
-in {
-  config = {
-    programs.waybar = {
-      inherit package;
-      enable = true;
-      systemd.enable = true;
-      settings = [{
-        layer = "top";
-        position = "top";
-        height = 26;
-        output = [ "DP-1" "eDP-1" "HEADLESS-1" ];
-        modules-left = [ "sway/workspaces" "sway/mode" ];
-        modules-center = [ "sway/window" ];
-        modules-right = [
-          "idle_inhibitor"
-          "pulseaudio"
-          "network"
-          "cpu"
-          "memory"
-          "backlight"
-          "tray"
-          "clock"
-        ];
-
-        modules = { "sway/workspaces".all-outputs = true; };
-      }];
-    };
-
-    # Remove when https://github.com/nix-community/home-manager/issues/1686 is
-    # fixed.
-    test.asserts.warnings.enable = false;
-
-    nmt.description = ''
-      Test for the broken configuration
-      https://github.com/nix-community/home-manager/pull/1329#issuecomment-653253069
-    '';
-    nmt.script = ''
-      assertPathNotExists home-files/.config/waybar/style.css
-      assertFileContent \
-        home-files/.config/waybar/config \
-        ${expected}
-    '';
-  };
-}
diff --git a/tests/modules/programs/waybar/default.nix b/tests/modules/programs/waybar/default.nix
index cac5de66..9ffebe24 100644
--- a/tests/modules/programs/waybar/default.nix
+++ b/tests/modules/programs/waybar/default.nix
@@ -3,6 +3,5 @@
     ./systemd-with-graphical-session-target.nix;
   waybar-styling = ./styling.nix;
   waybar-settings-complex = ./settings-complex.nix;
-  # Broken configuration from https://github.com/nix-community/home-manager/pull/1329#issuecomment-653253069
-  waybar-broken-settings = ./broken-settings.nix;
+  waybar-warnings = ./warnings-tests.nix;
 }
diff --git a/tests/modules/programs/waybar/settings-complex.nix b/tests/modules/programs/waybar/settings-complex.nix
index 16ceccb6..1756ae12 100644
--- a/tests/modules/programs/waybar/settings-complex.nix
+++ b/tests/modules/programs/waybar/settings-complex.nix
@@ -50,10 +50,6 @@ in {
       }];
     };
 
-    # Remove when https://github.com/nix-community/home-manager/issues/1686 is
-    # fixed.
-    test.asserts.warnings.enable = false;
-
     nmt.script = ''
       assertPathNotExists home-files/.config/waybar/style.css
       assertFileContent \
diff --git a/tests/modules/programs/waybar/warnings-tests.nix b/tests/modules/programs/waybar/warnings-tests.nix
new file mode 100644
index 00000000..f7912dba
--- /dev/null
+++ b/tests/modules/programs/waybar/warnings-tests.nix
@@ -0,0 +1,64 @@
+{ config, pkgs, lib, ... }:
+
+with lib;
+
+let
+  package = pkgs.writeScriptBin "dummy-waybar" "" // { outPath = "@waybar@"; };
+in {
+  config = {
+    programs.waybar = {
+      inherit package;
+      enable = true;
+      settings = [{
+        modules-left = [ "custom/my-module" ];
+        modules-center =
+          [ "this_module_is_not_a_valid_default_module_nor_custom_module" ];
+        modules-right = [
+          "battery#bat1" # CSS identifier is allowed
+          "custom/this_custom_module_doesn't_have_a_definition_in_modules"
+        ];
+
+        modules = {
+          "custom/this_module_is_not_referenced" = { };
+          "battery#bat1" = { };
+          "custom/my-module" = { };
+        };
+      }];
+    };
+
+    test.asserts.warnings.expected = [
+      "The module 'this_module_is_not_a_valid_default_module_nor_custom_module' defined in 'programs.waybar.settings.[].modules-center' is neither a default module or a custom module declared in 'programs.waybar.settings.[].modules'"
+
+      "The module 'custom/this_custom_module_doesn't_have_a_definition_in_modules' defined in 'programs.waybar.settings.[].modules-right' is neither a default module or a custom module declared in 'programs.waybar.settings.[].modules'"
+
+      "The module 'custom/this_module_is_not_referenced' defined in 'programs.waybar.settings.[].modules' is not referenced in either `modules-left`, `modules-center` or `modules-right` of Waybar's options"
+    ];
+
+    nmt.script = ''
+      assertPathNotExists home-files/.config/waybar/style.css
+      assertFileContent \
+        home-files/.config/waybar/config \
+        ${
+          pkgs.writeText "expected-json" ''
+            [
+              {
+                "battery#bat1": {},
+                "custom/my-module": {},
+                "custom/this_module_is_not_referenced": {},
+                "modules-center": [
+                  "this_module_is_not_a_valid_default_module_nor_custom_module"
+                ],
+                "modules-left": [
+                  "custom/my-module"
+                ],
+                "modules-right": [
+                  "battery#bat1",
+                  "custom/this_custom_module_doesn't_have_a_definition_in_modules"
+                ]
+              }
+            ]
+          ''
+        }
+    '';
+  };
+}