diff --git a/esphome/components/web_server/web_server.cpp b/esphome/components/web_server/web_server.cpp
index 9b36a736fd..d827c194aa 100644
--- a/esphome/components/web_server/web_server.cpp
+++ b/esphome/components/web_server/web_server.cpp
@@ -1711,7 +1711,7 @@ void WebServer::handle_water_heater_request(AsyncWebServerRequest *request, cons
                              &water_heater::WaterHeaterCall::set_target_temperature);
     if (request->hasParam("mode")) {
       std::string mode = request->getParam("mode")->value();
-      call.set_mode(mode.c_str());
+      call.set_mode(mode);
     }
 
     this->defer([call]() mutable { call.perform(); });