diff --git a/controller/search.js b/controller/search.js
index 0ed1f9cd..2e8ca7e2 100644
--- a/controller/search.js
+++ b/controller/search.js
@@ -1,5 +1,4 @@
 var service = { search: require('../service/search') };
-var types = require ( '../helper/types' );
 
 function setup( backend, query ){
 
@@ -16,11 +15,9 @@ function setup( backend, query ){
       body: query( req.clean )
     };
 
-    // don't directly set cmd.type from types helper to avoid sometimes
-    // setting cmd.type to undefined (having the key not set is cleaner)
-    var type = types(req.clean.types);
-    if (type !== undefined) {
-      cmd.type = type;
+    if (req.clean.type !== undefined) {
+      cmd.type = req.clean.type;
+      delete req.clean.type; // remove type from clean to avoid clutter
     }
 
     // query backend
diff --git a/middleware/_types.js b/middleware/_types.js
new file mode 100644
index 00000000..8b12719f
--- /dev/null
+++ b/middleware/_types.js
@@ -0,0 +1,27 @@
+var types_helper = require( '../helper/types' );
+
+/**
+ * Validate the types specified to be searched.
+ *
+ * Elasticsearch interprets an empty array of types as "search anything" rather
+ * than "search nothing", so in the case of an empty array, return an error
+ * message instead of searching at all.
+ */
+function middleware(req, res, next) {
+  var types = types_helper(req.clean.types);
+
+  if (types !== undefined && types.length !== undefined) {
+   if (types.length === 0) {
+    var err = 'You have specified both the `source` and `layers` ' +
+    'parameters in a combination that will return no results.';
+    res.status(400); // 400 Bad Request
+    return next(err);
+   } else {
+     req.clean.type = types;
+   }
+  }
+
+  next();
+}
+
+module.exports = middleware;
diff --git a/routes/v1.js b/routes/v1.js
index 27bda868..24ecccf2 100644
--- a/routes/v1.js
+++ b/routes/v1.js
@@ -9,6 +9,11 @@ var sanitisers = {
   reverse: require('../sanitiser/reverse')
 };
 
+/** ----------------------- middleware ------------------------ **/
+var middleware = {
+  types: require('../middleware/_types')
+};
+
 /** ----------------------- controllers ----------------------- **/
 
 var controllers     = {
@@ -45,6 +50,7 @@ function addRoutes(app, peliasConfig) {
     ]),
     search: createRouter([
       sanitisers.search.middleware,
+      middleware.types,
       controllers.search(),
       postProc.confidenceScores(peliasConfig),
       postProc.renamePlacenames(),
diff --git a/sanitiser/search.js b/sanitiser/search.js
index d226dbd9..17409587 100644
--- a/sanitiser/search.js
+++ b/sanitiser/search.js
@@ -4,6 +4,7 @@ var _sanitize = require('../sanitiser/_sanitize'),
       input: require('../sanitiser/_input'),
       size: require('../sanitiser/_size'),
       layers: require('../sanitiser/_layers'),
+      source: require('../sanitiser/_source'),
       details: require('../sanitiser/_details'),
       latlonzoom: require('../sanitiser/_geo')
     };