diff --git a/lib/util.js b/lib/util.js
index 5c07903f..10953f68 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -430,7 +430,8 @@ const util = class util {
     cacheableParams.qualityGrade = queryDup.quality_grade ? queryDup.quality_grade : null;
     cacheableParams.spam = queryDup.spam ? queryDup.spam : null;
     cacheableParams.captive = queryDup.captive ? queryDup.captive : null;
-    cacheableParams.perPage = queryDup.per_page ? queryDup.per_page : null;
+    cacheableParams.perPage = ( _.isNumber( queryDup.per_page ) || queryDup.per_page )
+      ? queryDup.per_page : null;
     cacheableParams.order = queryDup.order ? queryDup.order : null;
     cacheableParams.orderBy = queryDup.order_by ? queryDup.order_by : null;
     cacheableParams.returnBounds = queryDup.return_bounds ? queryDup.return_bounds : null;
diff --git a/test/util.js b/test/util.js
index 990f1bb8..6a8a9800 100644
--- a/test/util.js
+++ b/test/util.js
@@ -194,6 +194,10 @@ describe( "util", ( ) => {
       expectParamInCacheKey( "place_id", 1, "placeID" );
     } );
 
+    it( "allows queries with numeric per_page value of 0 to be cached for obs search", ( ) => {
+      expectParamInCacheKey( "per_page", 0, "perPage" );
+    } );
+
     it( "does not allow queries with place_id to be cached for obs search when logged in", ( ) => {
       const req = {
         query: {