diff --git a/web/modules/custom/joinup_search/joinup_search.install b/web/modules/custom/joinup_search/joinup_search.install
new file mode 100644
index 0000000000..9be6bc178e
--- /dev/null
+++ b/web/modules/custom/joinup_search/joinup_search.install
@@ -0,0 +1,65 @@
+<?php
+
+/**
+ * @file
+ * Install, update and uninstall functions for Joinup Search module.
+ */
+
+declare(strict_types = 1);
+
+use Drupal\Component\Serialization\Json;
+use Drupal\search_api_solr\Utility\Utility;
+use Laminas\Diactoros\Uri;
+
+/**
+ * Implements hook_requirements().
+ */
+function joinup_search_requirements(string $phase): array {
+  $requirements = [];
+  if ($phase !== 'runtime') {
+    return $requirements;
+  }
+
+  $http_client = \Drupal::httpClient();
+  $site_hash = Utility::getSiteHash();
+  foreach (['published', 'unpublished'] as $index_id) {
+    $endpoint = \Drupal::config("search_api.server.solr_{$index_id}")
+      ->get('backend_config.connector_config');
+    $uri = (string) (new Uri())
+      ->withScheme($endpoint['scheme'])
+      ->withHost($endpoint['host'])
+      ->withPort($endpoint['port'])
+      ->withPath(rtrim($endpoint['path'], '/') . "/{$endpoint['core']}/select")
+      ->withQuery(http_build_query([
+        'fq' => "-hash:{$site_hash}",
+        'q' => '*:*',
+        'wt' => 'json',
+       ]));
+
+    try {
+      $response = $http_client->get($uri);
+    }
+    catch (\Throwable $exception) {
+      // Ignore error, it's already covered by search_api_solr module.
+      // @see search_api_solr_requirements()
+      continue;
+    }
+
+    $num_found = Json::decode($response->getBody()->getContents())['response']['numFound'];
+    if ($num_found) {
+      $requirements["solr_data:{$index_id}"] = [
+        'severity' => REQUIREMENT_ERROR,
+        'title' => t('Solr index: %index', ['%index' => $index_id]),
+        'value' => t('Found @count entries with invalid site hash', [
+          '@count' => $num_found,
+        ]),
+        'description' => t('The valid site hash is %hash. Retrieve the invalid entries with this <a href=":uri">query</a>.', [
+          '%hash' => $site_hash,
+          ':uri' => $uri,
+         ]),
+      ];
+    }
+  }
+
+  return $requirements;
+}