diff --git a/pingdom/resource_pingdom_check.go b/pingdom/resource_pingdom_check.go
index 141e2af1..3de349a5 100644
--- a/pingdom/resource_pingdom_check.go
+++ b/pingdom/resource_pingdom_check.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/validation"
 	"github.com/nordcloud/go-pingdom/pingdom"
 )
 
@@ -27,114 +28,102 @@ func resourcePingdomCheck() *schema.Resource {
 			"name": {
 				Type:     schema.TypeString,
 				Required: true,
-				ForceNew: false,
 			},
 			"host": {
 				Type:     schema.TypeString,
 				Required: true,
-				ForceNew: false,
 			},
 			"type": {
-				Type:     schema.TypeString,
-				Required: true,
-				ForceNew: true,
+				Type:         schema.TypeString,
+				Required:     true,
+				ForceNew:     true,
+				ValidateFunc: validation.StringInSlice([]string{"http", "tcp", "ping"}, false),
 			},
 			"paused": {
 				Type:     schema.TypeBool,
 				Optional: true,
-				ForceNew: false,
-				Computed: true,
+				Default:  false,
 			},
 			"responsetime_threshold": {
 				Type:     schema.TypeInt,
 				Optional: true,
-				ForceNew: false,
 				Computed: true,
 			},
 			"resolution": {
-				Type:     schema.TypeInt,
-				Optional: true,
-				ForceNew: false,
-				Computed: true,
+				Type:         schema.TypeInt,
+				Optional:     true,
+				ForceNew:     false,
+				Default:      5,
+				ValidateFunc: validation.IntInSlice([]int{1, 5, 15, 30, 60}),
 			},
 			"sendnotificationwhendown": {
 				Type:     schema.TypeInt,
 				Optional: true,
-				ForceNew: false,
-				Computed: true,
+				Default:  2,
 			},
 			"notifyagainevery": {
 				Type:     schema.TypeInt,
 				Optional: true,
-				ForceNew: false,
 				Computed: true,
 			},
 			"notifywhenbackup": {
 				Type:     schema.TypeBool,
 				Optional: true,
-				ForceNew: false,
-				Computed: true,
+				Default:  true,
 			},
 			"integrationids": {
 				Type:     schema.TypeSet,
 				Optional: true,
-				ForceNew: false,
 				Elem:     &schema.Schema{Type: schema.TypeInt},
 			},
 			"encryption": {
 				Type:     schema.TypeBool,
 				Optional: true,
-				ForceNew: false,
 				Computed: true,
 			},
 			"url": {
 				Type:             schema.TypeString,
 				Optional:         true,
-				ForceNew:         false,
 				Default:          "/",
 				DiffSuppressFunc: diffSuppressIfNotHTTPCheck,
 			},
 			"port": {
-				Type:     schema.TypeInt,
-				Optional: true,
-				ForceNew: false,
-				Computed: true,
+				Type:         schema.TypeInt,
+				Optional:     true,
+				ForceNew:     false,
+				Computed:     true,
+				ValidateFunc: validation.IsPortNumber,
 			},
 			"username": {
 				Type:     schema.TypeString,
 				Optional: true,
-				ForceNew: false,
 			},
 			"password": {
-				Type:     schema.TypeString,
-				Optional: true,
-				ForceNew: false,
+				Type:      schema.TypeString,
+				Optional:  true,
+				ForceNew:  false,
+				Sensitive: true,
 			},
 			"shouldcontain": {
 				Type:     schema.TypeString,
 				Optional: true,
-				ForceNew: false,
 			},
 			"shouldnotcontain": {
 				Type:     schema.TypeString,
 				Optional: true,
-				ForceNew: false,
 			},
 			"postdata": {
 				Type:     schema.TypeString,
 				Optional: true,
-				ForceNew: false,
 			},
 			"requestheaders": {
 				Type:     schema.TypeMap,
 				Optional: true,
-				ForceNew: false,
 				Elem:     &schema.Schema{Type: schema.TypeString},
 			},
 			"tags": {
 				Type:     schema.TypeString,
 				Optional: true,
-				ForceNew: false,
 				StateFunc: func(val interface{}) string {
 					return sortString(val.(string), ",")
 				},
@@ -142,51 +131,42 @@ func resourcePingdomCheck() *schema.Resource {
 			"probefilters": {
 				Type:     schema.TypeString,
 				Optional: true,
-				ForceNew: false,
 			},
 			"userids": {
 				Type:     schema.TypeSet,
 				Optional: true,
-				ForceNew: false,
 				Elem:     &schema.Schema{Type: schema.TypeInt},
 			},
 			"teamids": {
 				Type:     schema.TypeSet,
 				Optional: true,
-				ForceNew: false,
 				Elem:     &schema.Schema{Type: schema.TypeInt},
 			},
 			"stringtosend": {
 				Type:     schema.TypeString,
 				Optional: true,
-				ForceNew: false,
 			},
 			"stringtoexpect": {
 				Type:     schema.TypeString,
 				Optional: true,
-				ForceNew: false,
 			},
 			"expectedip": {
 				Type:     schema.TypeString,
 				Optional: true,
-				ForceNew: false,
 			},
 			"nameserver": {
 				Type:     schema.TypeString,
 				Optional: true,
-				ForceNew: false,
 			},
 			"verify_certificate": {
 				Type:             schema.TypeBool,
 				Optional:         true,
-				ForceNew:         false,
 				Default:          true,
 				DiffSuppressFunc: diffSuppressIfNotHTTPCheck,
 			},
 			"ssl_down_days_before": {
 				Type:     schema.TypeInt,
 				Optional: true,
-				ForceNew: false,
 				Computed: true,
 			},
 		},
diff --git a/pingdom/resource_pingdom_contact.go b/pingdom/resource_pingdom_contact.go
index 181aad5d..88a4e442 100644
--- a/pingdom/resource_pingdom_contact.go
+++ b/pingdom/resource_pingdom_contact.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/validation"
 	"github.com/nordcloud/go-pingdom/pingdom"
 )
 
@@ -49,9 +50,10 @@ func resourcePingdomContact() *schema.Resource {
 							Required: true,
 						},
 						"provider": {
-							Type:     schema.TypeString,
-							Optional: true,
-							Default:  "nexmo",
+							Type:         schema.TypeString,
+							Optional:     true,
+							Default:      "nexmo",
+							ValidateFunc: validation.StringInSlice([]string{"nexmo", "bulksms", "esendex", "cellsynt"}, false),
 						},
 					},
 				},
diff --git a/pingdom/resource_pingdom_maintenance.go b/pingdom/resource_pingdom_maintenance.go
index f98f52c5..45509859 100644
--- a/pingdom/resource_pingdom_maintenance.go
+++ b/pingdom/resource_pingdom_maintenance.go
@@ -2,11 +2,13 @@ package pingdom
 
 import (
 	"context"
+	"strconv"
+	"strings"
+
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/validation"
 	"github.com/nordcloud/go-pingdom/pingdom"
-	"strconv"
-	"strings"
 )
 
 func resourcePingdomMaintenance() *schema.Resource {
@@ -37,9 +39,10 @@ func resourcePingdomMaintenance() *schema.Resource {
 				Computed: true,
 			},
 			"recurrencetype": {
-				Type:     schema.TypeString,
-				Optional: true,
-				Default:  "none",
+				Type:         schema.TypeString,
+				Optional:     true,
+				Default:      "none",
+				ValidateFunc: validation.StringInSlice([]string{"none", "day", "week", "month"}, false),
 			},
 			"repeatevery": {
 				Type:     schema.TypeInt,
diff --git a/pingdom/resource_pingdom_team.go b/pingdom/resource_pingdom_team.go
index 58c35aed..e580c5ab 100644
--- a/pingdom/resource_pingdom_team.go
+++ b/pingdom/resource_pingdom_team.go
@@ -23,12 +23,10 @@ func resourcePingdomTeam() *schema.Resource {
 			"name": {
 				Type:     schema.TypeString,
 				Required: true,
-				ForceNew: false,
 			},
 			"member_ids": {
 				Type:     schema.TypeSet,
 				Optional: true,
-				ForceNew: false,
 				Elem:     &schema.Schema{Type: schema.TypeInt},
 			},
 		},
diff --git a/pingdom/resource_pingdom_tms_check.go b/pingdom/resource_pingdom_tms_check.go
index a825a2ed..2eb9c809 100644
--- a/pingdom/resource_pingdom_tms_check.go
+++ b/pingdom/resource_pingdom_tms_check.go
@@ -9,6 +9,7 @@ import (
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/validation"
 	"github.com/nordcloud/go-pingdom/pingdom"
 )
 
@@ -62,10 +63,11 @@ func resourcePingdomTmsCheck() *schema.Resource {
 				Optional: true,
 				Elem:     &schema.Schema{Type: schema.TypeInt},
 			},
-			"interval": { //  [5 10 20 60 720 1440]
-				Type:     schema.TypeInt,
-				Optional: true,
-				Default:  10,
+			"interval": {
+				Type:         schema.TypeInt,
+				Optional:     true,
+				Default:      10,
+				ValidateFunc: validation.IntInSlice([]int{5, 10, 20, 60, 720, 1440}),
 			},
 			"metadata": {
 				Type:     schema.TypeList,
@@ -95,18 +97,21 @@ func resourcePingdomTmsCheck() *schema.Resource {
 				},
 			},
 			"region": {
-				Type:     schema.TypeString,
-				Optional: true,
-				Default:  "us-east",
+				Type:         schema.TypeString,
+				Optional:     true,
+				Default:      "us-east",
+				ValidateFunc: validation.StringInSlice([]string{"us-east", "us-west", "eu", "au"}, false),
 			},
 			"send_notification_when_down": {
 				Type:     schema.TypeInt,
 				Optional: true,
+				Default:  1,
 			},
 			"security_level": {
-				Type:     schema.TypeString,
-				Optional: true,
-				Default:  "high",
+				Type:         schema.TypeString,
+				Optional:     true,
+				Default:      "high",
+				ValidateFunc: validation.StringInSlice([]string{"high", "low"}, false),
 			},
 			"tags": {
 				Type:     schema.TypeString,