diff --git a/config/database.yml b/config/database.yml
index 94b772eb511..2fab24e56cd 100644
--- a/config/database.yml
+++ b/config/database.yml
@@ -43,7 +43,7 @@ production:
   uri: <%= uri = URI.parse(ENV['POSTGRES_URL'] ? ENV['POSTGRES_URL'] : "pg://localhost") %>
   socket: <%= ENV['POSTGRES_SOCKET'] %>
   host: <%= uri.host  %>
-  port: <%= uri.port || 5432 %>
+  port: <%= uri.port || (ENV['POSTGRES_SOCKET'] ? nil : 5432) %>
   database: <%= ENV['POSTGRES_DB'] || "discourse" %>
   username: <%= uri.user %>
   password: <%= uri.password %>