diff --git a/client/allocrunner/alloc_runner_test.go b/client/allocrunner/alloc_runner_test.go
index 8aaba67b4..90e5b5c85 100644
--- a/client/allocrunner/alloc_runner_test.go
+++ b/client/allocrunner/alloc_runner_test.go
@@ -143,13 +143,20 @@ func TestAllocRunner_TaskLeader_KillTG(t *testing.T) {
 
 func TestAllocRunner_TaskGroup_ShutdownDelay(t *testing.T) {
 	t.Parallel()
-	shutdownDelay := 1 * time.Second
 
 	alloc := mock.Alloc()
 	tr := alloc.AllocatedResources.Tasks[alloc.Job.TaskGroups[0].Tasks[0].Name]
 	alloc.Job.TaskGroups[0].RestartPolicy.Attempts = 0
 
-	// Create 3 tasks in the task group
+	// Create a group service
+	tg := alloc.Job.TaskGroups[0]
+	tg.Services = []*structs.Service{
+		{
+			Name: "shutdown_service",
+		},
+	}
+
+	// Create two tasks in the  group
 	task := alloc.Job.TaskGroups[0].Tasks[0]
 	task.Name = "follower1"
 	task.Driver = "mock_driver"
@@ -170,6 +177,7 @@ func TestAllocRunner_TaskGroup_ShutdownDelay(t *testing.T) {
 	alloc.AllocatedResources.Tasks[task2.Name] = tr
 
 	// Set a shutdown delay
+	shutdownDelay := 1 * time.Second
 	alloc.Job.TaskGroups[0].ShutdownDelay = &shutdownDelay
 
 	conf, cleanup := testAllocRunnerConfig(t, alloc)
@@ -204,7 +212,7 @@ func TestAllocRunner_TaskGroup_ShutdownDelay(t *testing.T) {
 	upd.Reset()
 
 	// Stop alloc
-	now := time.Now()
+	shutdownInit := time.Now()
 	update := alloc.Copy()
 	update.DesiredStatus = structs.AllocDesiredStatusStop
 	ar.Update(update)
@@ -231,9 +239,33 @@ func TestAllocRunner_TaskGroup_ShutdownDelay(t *testing.T) {
 		t.Fatalf("err: %v", err)
 	})
 
+	// Get consul client operations
+	consulClient := conf.Consul.(*cconsul.MockConsulServiceClient)
+	consulOpts := consulClient.GetOps()
+	var groupRemoveOp cconsul.MockConsulOp
+	for _, op := range consulOpts {
+		// Grab the first deregistration request
+		if op.Op == "remove" && op.Name == "group-web" {
+			groupRemoveOp = op
+			break
+		}
+	}
+
+	// Ensure remove operation is close to shutdown initiation
+	require.True(t, groupRemoveOp.OccurredAt.Sub(shutdownInit) < 100*time.Millisecond)
+
 	last = upd.Last()
-	require.Greater(t, last.TaskStates["leader"].FinishedAt.UnixNano(), now.Add(shutdownDelay).UnixNano())
-	require.Greater(t, last.TaskStates["follower1"].FinishedAt.UnixNano(), now.Add(shutdownDelay).UnixNano())
+	minShutdown := shutdownInit.Add(task.ShutdownDelay)
+	leaderFinished := last.TaskStates["leader"].FinishedAt
+	followerFinished := last.TaskStates["follower1"].FinishedAt
+
+	// Check that both tasks shut down after min possible shutdown time
+	require.Greater(t, leaderFinished.UnixNano(), minShutdown.UnixNano())
+	require.Greater(t, followerFinished.UnixNano(), minShutdown.UnixNano())
+
+	// Check that there is at least shutdown_delay between consul
+	// remove operation and task finished at time
+	require.True(t, leaderFinished.Sub(groupRemoveOp.OccurredAt) > shutdownDelay)
 }
 
 // TestAllocRunner_TaskLeader_StopTG asserts that when stopping an alloc with a
diff --git a/client/allocrunner/groupservice_hook.go b/client/allocrunner/groupservice_hook.go
index a02cc9d5b..1cd2f10df 100644
--- a/client/allocrunner/groupservice_hook.go
+++ b/client/allocrunner/groupservice_hook.go
@@ -139,9 +139,10 @@ func (h *groupServiceHook) PreKill() {
 	h.deregistered = true
 
 	h.logger.Debug("waiting before removing group service", "shutdown_delay", h.delay)
-	select {
-	case <-time.After(h.delay):
-	}
+
+	// Wait for specified shutdown_delay
+	// this will block an agent from shutting down
+	<-time.After(h.delay)
 }
 
 func (h *groupServiceHook) Postrun() error {
diff --git a/client/allocrunner/interfaces/runner_lifecycle.go b/client/allocrunner/interfaces/runner_lifecycle.go
index f0b2e6c74..33713b2c1 100644
--- a/client/allocrunner/interfaces/runner_lifecycle.go
+++ b/client/allocrunner/interfaces/runner_lifecycle.go
@@ -16,6 +16,15 @@ type RunnerPrerunHook interface {
 	Prerun() error
 }
 
+// RunnerPreKillHooks are executed inside of KillTasks before
+// iterating and killing each task. It will run before the Leader
+// task is killed.
+type RunnerPreKillHook interface {
+	RunnerHook
+
+	PreKill()
+}
+
 // RunnerPostrunHooks are executed after calling TaskRunner.Run, even for
 // terminal allocations. Therefore Postrun hooks must be safe to call without
 // first calling Prerun hooks.
@@ -53,10 +62,3 @@ type ShutdownHook interface {
 
 	Shutdown()
 }
-
-//
-type RunnerPreKillHook interface {
-	RunnerHook
-
-	PreKill()
-}
diff --git a/client/consul/consul_testing.go b/client/consul/consul_testing.go
index 6fb926068..75307eae8 100644
--- a/client/consul/consul_testing.go
+++ b/client/consul/consul_testing.go
@@ -3,6 +3,7 @@ package consul
 import (
 	"fmt"
 	"sync"
+	"time"
 
 	log "github.com/hashicorp/go-hclog"
 
@@ -12,9 +13,10 @@ import (
 
 // MockConsulOp represents the register/deregister operations.
 type MockConsulOp struct {
-	Op      string // add, remove, or update
-	AllocID string
-	Name    string // task or group name
+	Op         string // add, remove, or update
+	AllocID    string
+	Name       string // task or group name
+	OccurredAt time.Time
 }
 
 func NewMockConsulOp(op, allocID, name string) MockConsulOp {
@@ -25,9 +27,10 @@ func NewMockConsulOp(op, allocID, name string) MockConsulOp {
 		panic(fmt.Errorf("invalid consul op: %s", op))
 	}
 	return MockConsulOp{
-		Op:      op,
-		AllocID: allocID,
-		Name:    name,
+		Op:         op,
+		AllocID:    allocID,
+		Name:       name,
+		OccurredAt: time.Now(),
 	}
 }
 
diff --git a/nomad/structs/structs.go b/nomad/structs/structs.go
index 5397b5bb0..879ccb482 100644
--- a/nomad/structs/structs.go
+++ b/nomad/structs/structs.go
@@ -3547,9 +3547,9 @@ func (j *Job) Validate() error {
 			taskGroups[tg.Name] = idx
 		}
 
-		// if tg.ShutdownDelay < 0 {
-		// 	mErr.Errors = append(mErr.Errors, errors.New("ShutdownDelay must be a positive value"))
-		// }
+		if tg.ShutdownDelay != nil && *tg.ShutdownDelay < 0 {
+			mErr.Errors = append(mErr.Errors, errors.New("ShutdownDelay must be a positive value"))
+		}
 
 		if j.Type == "system" && tg.Count > 1 {
 			mErr.Errors = append(mErr.Errors,