diff --git a/pkg/cluster/cluster.go b/pkg/cluster/cluster.go
index d740260d2..e97843373 100644
--- a/pkg/cluster/cluster.go
+++ b/pkg/cluster/cluster.go
@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"reflect"
 	"regexp"
+	"strconv"
 	"sync"
 	"time"
 
@@ -633,6 +634,28 @@ func (c *Cluster) Update(oldSpec, newSpec *acidv1.Postgresql) error {
 		}
 	}()
 
+	// delete persistent volume claim after scale down
+	if oldSpec.Spec.NumberOfInstances > newSpec.Spec.NumberOfInstances {
+		c.logger.Debug("deleting pvc of shut down pods")
+
+		for i := oldSpec.Spec.NumberOfInstances - 1; i >= newSpec.Spec.NumberOfInstances; i-- {
+
+			// Scaling down to 0 replicas is not cluster deletion so keep the last pvc.
+			// Operator will remove it only when explicit "kubectl pg delete" is issued
+			if i == 0 {
+				c.logger.Info("cluster scaled down to 0 pods; skipping deletion of the last pvc")
+				break
+			}
+
+			podIndex := strconv.Itoa(int(i))
+			pvcName := "pgdata-" + c.Name + "-" + podIndex
+			if err := c.KubeClient.PersistentVolumeClaims(c.Namespace).Delete(pvcName, c.deleteOptions); err != nil {
+				c.logger.Warningf("could not delete PersistentVolumeClaim: %v", err)
+				// failing to delete pvc does not fail the update; Sync() may also delete unused PVCs later
+			}
+		}
+	}
+
 	// pod disruption budget
 	if oldSpec.Spec.NumberOfInstances != newSpec.Spec.NumberOfInstances {
 		c.logger.Debug("syncing pod disruption budgets")
diff --git a/pkg/cluster/sync.go b/pkg/cluster/sync.go
index b04ff863b..ffe1cb28e 100644
--- a/pkg/cluster/sync.go
+++ b/pkg/cluster/sync.go
@@ -2,6 +2,7 @@ package cluster
 
 import (
 	"fmt"
+	"strconv"
 
 	batchv1beta1 "k8s.io/api/batch/v1beta1"
 	v1 "k8s.io/api/core/v1"
@@ -108,6 +109,24 @@ func (c *Cluster) Sync(newSpec *acidv1.Postgresql) error {
 		}
 	}
 
+	// remove unused PVCs in case deleting them during scale down failed; see Update()
+	// the last pvc stays until the cluster is explicitly deleted as opposed to being scaled down to 0 pods
+	if c.getNumberOfInstances(&c.Spec) > 0 {
+
+		for i := c.getNumberOfInstances(&c.Spec); ; i++ {
+			podIndex := strconv.Itoa(int(i))
+			pvcName := "pgdata-" + c.Name + "-" + podIndex
+			if err := c.KubeClient.PersistentVolumeClaims(c.Namespace).Delete(pvcName, c.deleteOptions); err != nil {
+				if k8sutil.ResourceNotFound(err) {
+					// no more pvcs to delete
+					break
+				}
+				c.logger.Warningf("could not delete PersistentVolumeClaim: %v", err)
+				// next Sync() or Update() will retry
+			}
+		}
+	}
+
 	return err
 }