diff --git a/charts/cluster/templates/prometheus-rule.yaml b/charts/cluster/templates/prometheus-rule.yaml
index fc3f35cb4d..2af43498c2 100644
--- a/charts/cluster/templates/prometheus-rule.yaml
+++ b/charts/cluster/templates/prometheus-rule.yaml
@@ -17,7 +17,7 @@ spec:
         {{- $_ := set $dict "namespace"   (include "cluster.namespace" .) -}}
         {{- $_ := set $dict "cluster"     (include "cluster.fullname" .) -}}
         {{- $_ := set $dict "labels"      (dict "job" "{{ $labels.job }}" "node" "{{ $labels.node }}" "pod" "{{ $labels.pod }}") -}}
-        {{- $_ := set $dict "podSelector" (printf "%s-([1-9][0-9]*)$" (include "cluster.fullname" .)) -}}
+        {{- $_ := set $dict "podSelector" (printf "%s-([1-9][0-9]*)" (include "cluster.fullname" .)) -}}
         {{- $_ := set $dict "Values"      .Values -}}
         {{- $_ := set $dict "Template"    .Template -}}
         {{- range $path, $_ := .Files.Glob  "prometheus_rules/**.yaml" }}
diff --git a/charts/cluster/test/monitoring/01-monitoring_cluster-assert.yaml b/charts/cluster/test/monitoring/01-monitoring_cluster-assert.yaml
index ff2d676bcc..d5b561af79 100644
--- a/charts/cluster/test/monitoring/01-monitoring_cluster-assert.yaml
+++ b/charts/cluster/test/monitoring/01-monitoring_cluster-assert.yaml
@@ -120,6 +120,13 @@ spec:
         labels:
           environment: staging
           oncall: "false"
+      # the low disk space alerts must also match the WAL and tablespace PVCs
+      (rules[?alert == 'CNPGClusterLowDiskSpaceCritical'] | [0]):
+        (contains(expr, 'persistentvolumeclaim=~"monitoring-cluster-([1-9][0-9]*)-wal"')): true
+        (contains(expr, 'persistentvolumeclaim=~"monitoring-cluster-([1-9][0-9]*)-tbs.*"')): true
+      (rules[?alert == 'CNPGClusterLowDiskSpaceWarning'] | [0]):
+        (contains(expr, 'persistentvolumeclaim=~"monitoring-cluster-([1-9][0-9]*)-wal"')): true
+        (contains(expr, 'persistentvolumeclaim=~"monitoring-cluster-([1-9][0-9]*)-tbs.*"')): true
 ---
 apiVersion: v1
 kind: ConfigMap