diff --git a/values/prometheus/values/prometheus.yaml.gotmpl b/values/prometheus/values/prometheus.yaml.gotmpl
index 79a4db69..baf15c00 100644
--- a/values/prometheus/values/prometheus.yaml.gotmpl
+++ b/values/prometheus/values/prometheus.yaml.gotmpl
@@ -167,7 +167,7 @@ grafana:
   {{- if .Values.prometheus.grafana.persistence }}
   persistence:
     enabled: true
-    size: 10Gi
+    size: 20Gi
   {{- end }}
   ingress:
     enabled: true