diff --git a/CHANGELOG.md b/CHANGELOG.md
index f0a1ea2..940886d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -50,3 +50,5 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Bingo button not shown on refresh
 - bingo chat style (images too large)
 - backend now returns precise error messages
+- setting words won't result in deleting all of them and resaving
+- words can now only be set when no round is active
diff --git a/routes/bingo.js b/routes/bingo.js
index 4c53961..93cbc0e 100644
--- a/routes/bingo.js
+++ b/routes/bingo.js
@@ -236,6 +236,16 @@ class BingoDataManager {
         return await this._queryFirstResult(this.queries.addWord.sql, [lobbyId, word]);
     }
 
+    /**
+     * Removes a word from the lobby
+     * @param lobbyId {Number} - the id of the lobby
+     * @param wordId {Number} - the id of the word
+     * @returns {Promise<*>}
+     */
+    async removeWordFromLobby(lobbyId, wordId) {
+        return await this._queryFirstResult(this.queries.removeLobbyWord.sql, [lobbyId, wordId]);
+    }
+
     /**
      * Returns all words used in a lobby
      * @param lobbyId {Number} - the id of the lobby
@@ -303,6 +313,15 @@ class BingoDataManager {
         return await this._queryFirstResult(this.queries.addGrid.sql, [playerId, lobbyId, roundId]);
     }
 
+    /**
+     * Clears all grids for a lobby.
+     * @param lobbyId {Number} - the id of the lobby
+     * @returns {Promise<*>}
+     */
+    async clearGrids(lobbyId) {
+        return await this._queryFirstResult(this.queries.clearLobbyGrids.sql, [lobbyId]);
+    }
+
     /**
      * Adds a word to a grid with specific location
      * @param gridId {Number} - the id of the gird
@@ -1018,18 +1037,63 @@ class LobbyWrapper {
         return (result && result.player_id);
     }
 
+    /**
+     * Adds a word to the lobby
+     * @param word
+     * @returns {Promise<void>}
+     */
+    async addWord(word) {
+        await bdm.addWordToLobby(this.id, word);
+    }
+
+    /**
+     * Removes a word from the lobby
+     * @param wordId
+     * @returns {Promise<void>}
+     */
+    async removeWord(wordId) {
+        await bdm.removeWordFromLobby(this.id, wordId);
+    }
+
     /**
      * Sets the words of the lobby
      * @param words
      * @returns {Promise<void>}
      */
     async setWords(words) {
-        if (words.length > 0) {
-            await bdm.clearLobbyWords(this.id);
-            for (let word of words)
-                // eslint-disable-next-line no-await-in-loop
-                await bdm.addWordToLobby(this.id, word);
+        if (words.length > 0 && !await this.roundActive()) {
+            let {newWords, removedWords} = await this._filterWords(words);
+            for (let word of newWords)
+                await this.addWord(word);
+            for (let word of removedWords)
+                 await this.removeWord(word.id);
+        }
+    }
+
+    /**
+     * Filters the bingo words
+     * @param words
+     * @returns {Promise<{removedWords: *[], newWords: *[]}>}
+     * @private
+     */
+    async _filterWords(words) {
+        let curWords = await this.words();
+        let currentWords = [];
+        let currentWordContent = [];
+        for (let word of curWords) {
+            currentWordContent.push(await word.content());
+            currentWords.push({
+                id: word.id,
+                content: (await word.content())
+            });
         }
+        let newWords = words.filter(x => (!currentWordContent.includes(x)));
+        let removedWords = currentWords.filter(x => !words.includes(x.content));
+
+        return {
+            newWords: newWords,
+            removedWords: removedWords
+        };
     }
 
     /**
@@ -1074,6 +1138,9 @@ class LobbyWrapper {
         let currentRound = await this.currentRound();
         await currentRound.updateStatus(status);
         await bdm.addInfoMessage(this.id, `Admin set round status to ${status}`);
+
+        if (status === 'FINISHED')
+            await bdm.clearGrids(this.id);
         return currentRound;
     }
 }
@@ -1463,6 +1530,7 @@ router.graphqlResolver = async (req, res) => {
                         let username = await new PlayerWrapper(playerId).username();
                         if (result) {
                             await bdm.addInfoMessage(lobbyId, `**${username}** won!`);
+                            await bdm.clearGrids(lobbyId);
                             return currentRound;
                         } else {
                             res.status(500);
diff --git a/sql/bingo/createBingoTables.sql b/sql/bingo/createBingoTables.sql
index c6d7c3b..c6061d7 100644
--- a/sql/bingo/createBingoTables.sql
+++ b/sql/bingo/createBingoTables.sql
@@ -62,7 +62,7 @@ CREATE TABLE IF NOT EXISTS bingo.grids (
 -- grids_words table
 CREATE TABLE IF NOT EXISTS bingo.grid_words (
     grid_id serial references bingo.grids(id) ON DELETE CASCADE,
-    word_id serial references bingo.words(id) ON DELETE CASCADE,
+    word_id serial references bingo.words(id) ON DELETE RESTRICT,
     grid_row integer NOT NULL,
     grid_column integer NOT NULL,
     submitted boolean DEFAULT false,
diff --git a/sql/bingo/queries.yaml b/sql/bingo/queries.yaml
index 2638aa2..1056fbf 100644
--- a/sql/bingo/queries.yaml
+++ b/sql/bingo/queries.yaml
@@ -160,6 +160,13 @@ addWord:
 clearLobbyWords:
   sql: DELETE FROM bingo.words WHERE lobby_id = $1;
 
+# deletes a word of a lobby
+# params:
+# - {Number} - the id of the lobby
+# - {Number} - the id of the word
+removeLobbyWord:
+  sql: DELETE FROM bingo.words WHERE lobby_id = $1 AND id = $2;
+
 # returns all words for a bingo game (lobby)
 # params:
 # - {Number} - the id of the bingo lobby
@@ -180,6 +187,12 @@ getWordInfo:
 addGrid:
   sql: INSERT INTO bingo.grids (player_id, lobby_id, round_id) VALUES ($1, $2, $3) RETURNING *;
 
+# deletes all grids of a lobby
+# params:
+# - {Number} - the id of the lobby
+clearLobbyGrids:
+  sql: DELETE FROM bingo.grids WHERE lobby_id = $1;
+
 # returns the grid entry for a player and lobby id
 # params:
 # - {Number} - the id of the player