diff --git a/hydra-module.nix b/hydra-module.nix
index 37faaf00..b4253478 100644
--- a/hydra-module.nix
+++ b/hydra-module.nix
@@ -21,6 +21,9 @@ let
       SSL_CERT_FILE = "/etc/ssl/certs/ca-certificates.crt"; # Remove in 16.03
       PGPASSFILE = "${baseDir}/pgpass";
       NIX_REMOTE_SYSTEMS = concatStringsSep ":" cfg.buildMachinesFiles;
+    } // optionalAttrs (cfg.smtpHost != null) {
+      EMAIL_SENDER_TRANSPORT = "SMTP";
+      EMAIL_SENDER_TRANSPORT_host = cfg.smtpHost;
     } // hydraEnv // cfg.extraEnv;
 
   serverEnv = env //
@@ -112,6 +115,15 @@ in
         '';
       };
 
+      smtpHost = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        example = ["localhost"];
+        description = ''
+          Hostname of the SMTP server to use to send email.
+        '';
+      };
+
       tracker = mkOption {
         type = types.str;
         default = "";