Index: trunk/data/validator/combinations.mapcss
===================================================================
--- trunk/data/validator/combinations.mapcss	(revision 10361)
+++ trunk/data/validator/combinations.mapcss	(revision 10388)
@@ -366,2 +366,10 @@
   throwWarning: tr("{0} on a relation without {1}", "{0.key}", "{1.tag}");
 }
+
+/* #9182 */
+way[waterway][layer=~/^(-1|-2|-3|-4|-5)$/][!tunnel][culvert!=yes][covered!=yes][pipeline!=yes][location!=underground][eval(waylength()) > 400] {
+  throwWarning: tr("Long waterway with negative {0} but without a {1} tag. Remove {0} or add a {1} tag if applicable. Also check crossing bridges and their {0} tags.", "{1.key}", "{2.key}");
+}
+way[waterway][layer=~/^(-1|-2|-3|-4|-5)$/][!tunnel][culvert!=yes][covered!=yes][pipeline!=yes][location!=underground][eval(waylength()) < 400] {
+  throwOther: tr("Short waterway with negative {0} but without a {1} tag. Remove {0} or add a {1} tag if applicable. Also check crossing bridges and their {0} tags.", "{1.key}", "{2.key}");
+}