diff --git a/api/agent.go b/api/agent.go
index 67855c67f..1211cc6fd 100644
--- a/api/agent.go
+++ b/api/agent.go
@@ -198,27 +198,42 @@ func (a *Agent) ServiceDeregister(serviceID string) error {
 	return nil
 }
 
-// PassTTL is used to set a TTL check to the passing state
+// PassTTL is used to set a TTL check to the passing state.
+//
+// DEPRECATION NOTICE: This interface is deprecated in favor of UpdateTTL().
+// The client interface will be removed in 0.8 or changed to use
+// UpdateTTL()'s endpoint and the server endpoints will be removed in 0.9.
 func (a *Agent) PassTTL(checkID, note string) error {
 	return a.updateTTL(checkID, note, "pass")
 }
 
-// WarnTTL is used to set a TTL check to the warning state
+// WarnTTL is used to set a TTL check to the warning state.
+//
+// DEPRECATION NOTICE: This interface is deprecated in favor of UpdateTTL().
+// The client interface will be removed in 0.8 or changed to use
+// UpdateTTL()'s endpoint and the server endpoints will be removed in 0.9.
 func (a *Agent) WarnTTL(checkID, note string) error {
 	return a.updateTTL(checkID, note, "warn")
 }
 
-// FailTTL is used to set a TTL check to the failing state
+// FailTTL is used to set a TTL check to the failing state.
+//
+// DEPRECATION NOTICE: This interface is deprecated in favor of UpdateTTL().
+// The client interface will be removed in 0.8 or changed to use
+// UpdateTTL()'s endpoint and the server endpoints will be removed in 0.9.
 func (a *Agent) FailTTL(checkID, note string) error {
 	return a.updateTTL(checkID, note, "fail")
 }
 
 // updateTTL is used to update the TTL of a check. This is the internal
-// method that uses the old API that's present in Consul versions prior
-// to 0.6.4. Since Consul didn't have an analogous "update" API before it
-// seemed ok to break this (former) UpdateTTL in favor of the new UpdateTTL
-// below, but keep the old Pass/Warn/Fail methods using the old API under the
-// hood.
+// method that uses the old API that's present in Consul versions prior to
+// 0.6.4. Since Consul didn't have an analogous "update" API before it seemed
+// ok to break this (former) UpdateTTL in favor of the new UpdateTTL below,
+// but keep the old Pass/Warn/Fail methods using the old API under the hood.
+//
+// DEPRECATION NOTICE: This interface is deprecated in favor of UpdateTTL().
+// The client interface will be removed in 0.8 and the server endpoints will
+// be removed in 0.9.
 func (a *Agent) updateTTL(checkID, note, status string) error {
 	switch status {
 	case "pass":
@@ -240,8 +255,9 @@ func (a *Agent) updateTTL(checkID, note, status string) error {
 
 // checkUpdate is the payload for a PUT for a check update.
 type checkUpdate struct {
-	// Status us one of the structs.Health* states, "passing", "warning", or
-	// "critical".
+	// Status us one of the structs.Health* states: HealthPassing
+	// ("passing"), HealthWarning ("warning"), or HealthCritical
+	// ("critical").
 	Status string
 
 	// Output is the information to post to the UI for operators as the
diff --git a/api/agent_test.go b/api/agent_test.go
index a61245149..b188d7ce3 100644
--- a/api/agent_test.go
+++ b/api/agent_test.go
@@ -76,7 +76,7 @@ func TestAgent_Services(t *testing.T) {
 	}
 
 	// Checks should default to critical
-	if chk.Status != "critical" {
+	if chk.Status != HealthCritical {
 		t.Fatalf("Bad: %#v", chk)
 	}
 
@@ -97,7 +97,7 @@ func TestAgent_Services_CheckPassing(t *testing.T) {
 		Port: 8000,
 		Check: &AgentServiceCheck{
 			TTL:    "15s",
-			Status: "passing",
+			Status: HealthPassing,
 		},
 	}
 	if err := agent.ServiceRegister(reg); err != nil {
@@ -121,7 +121,7 @@ func TestAgent_Services_CheckPassing(t *testing.T) {
 		t.Fatalf("missing check: %v", checks)
 	}
 
-	if chk.Status != "passing" {
+	if chk.Status != HealthPassing {
 		t.Fatalf("Bad: %#v", chk)
 	}
 	if err := agent.ServiceDeregister("foo"); err != nil {
@@ -320,47 +320,47 @@ func TestAgent_SetTTLStatus(t *testing.T) {
 	if err := agent.WarnTTL("service:foo", "foo"); err != nil {
 		t.Fatalf("err: %v", err)
 	}
-	verify("warning", "foo")
+	verify(HealthWarning, "foo")
 
 	if err := agent.PassTTL("service:foo", "bar"); err != nil {
 		t.Fatalf("err: %v", err)
 	}
-	verify("passing", "bar")
+	verify(HealthPassing, "bar")
 
 	if err := agent.FailTTL("service:foo", "baz"); err != nil {
 		t.Fatalf("err: %v", err)
 	}
-	verify("critical", "baz")
+	verify(HealthCritical, "baz")
 
 	if err := agent.UpdateTTL("service:foo", "foo", "warn"); err != nil {
 		t.Fatalf("err: %v", err)
 	}
-	verify("warning", "foo")
+	verify(HealthWarning, "foo")
 
 	if err := agent.UpdateTTL("service:foo", "bar", "pass"); err != nil {
 		t.Fatalf("err: %v", err)
 	}
-	verify("passing", "bar")
+	verify(HealthPassing, "bar")
 
 	if err := agent.UpdateTTL("service:foo", "baz", "fail"); err != nil {
 		t.Fatalf("err: %v", err)
 	}
-	verify("critical", "baz")
+	verify(HealthCritical, "baz")
 
-	if err := agent.UpdateTTL("service:foo", "foo", "warning"); err != nil {
+	if err := agent.UpdateTTL("service:foo", "foo", HealthWarning); err != nil {
 		t.Fatalf("err: %v", err)
 	}
-	verify("warning", "foo")
+	verify(HealthWarning, "foo")
 
-	if err := agent.UpdateTTL("service:foo", "bar", "passing"); err != nil {
+	if err := agent.UpdateTTL("service:foo", "bar", HealthPassing); err != nil {
 		t.Fatalf("err: %v", err)
 	}
-	verify("passing", "bar")
+	verify(HealthPassing, "bar")
 
-	if err := agent.UpdateTTL("service:foo", "baz", "critical"); err != nil {
+	if err := agent.UpdateTTL("service:foo", "baz", HealthCritical); err != nil {
 		t.Fatalf("err: %v", err)
 	}
-	verify("critical", "baz")
+	verify(HealthCritical, "baz")
 
 	if err := agent.ServiceDeregister("foo"); err != nil {
 		t.Fatalf("err: %v", err)
@@ -390,7 +390,7 @@ func TestAgent_Checks(t *testing.T) {
 	if !ok {
 		t.Fatalf("missing check: %v", checks)
 	}
-	if chk.Status != "critical" {
+	if chk.Status != HealthCritical {
 		t.Fatalf("check not critical: %v", chk)
 	}
 
@@ -409,7 +409,7 @@ func TestAgent_CheckStartPassing(t *testing.T) {
 	reg := &AgentCheckRegistration{
 		Name: "foo",
 		AgentServiceCheck: AgentServiceCheck{
-			Status: "passing",
+			Status: HealthPassing,
 		},
 	}
 	reg.TTL = "15s"
@@ -425,7 +425,7 @@ func TestAgent_CheckStartPassing(t *testing.T) {
 	if !ok {
 		t.Fatalf("missing check: %v", checks)
 	}
-	if chk.Status != "passing" {
+	if chk.Status != HealthPassing {
 		t.Fatalf("check not passing: %v", chk)
 	}
 
@@ -580,7 +580,7 @@ func TestServiceMaintenance(t *testing.T) {
 	for _, check := range checks {
 		if strings.Contains(check.CheckID, "maintenance") {
 			found = true
-			if check.Status != "critical" || check.Notes != "broken" {
+			if check.Status != HealthCritical || check.Notes != "broken" {
 				t.Fatalf("bad: %#v", checks)
 			}
 		}
@@ -627,7 +627,7 @@ func TestNodeMaintenance(t *testing.T) {
 	for _, check := range checks {
 		if strings.Contains(check.CheckID, "maintenance") {
 			found = true
-			if check.Status != "critical" || check.Notes != "broken" {
+			if check.Status != HealthCritical || check.Notes != "broken" {
 				t.Fatalf("bad: %#v", checks)
 			}
 		}
diff --git a/api/catalog_test.go b/api/catalog_test.go
index 691c05618..3a3395ae6 100644
--- a/api/catalog_test.go
+++ b/api/catalog_test.go
@@ -157,7 +157,7 @@ func TestCatalog_Registration(t *testing.T) {
 		CheckID:   "service:redis1",
 		Name:      "Redis health check",
 		Notes:     "Script based health check",
-		Status:    "passing",
+		Status:    HealthPassing,
 		ServiceID: "redis1",
 	}
 
diff --git a/command/agent/agent_endpoint_test.go b/command/agent/agent_endpoint_test.go
index 2a3b14844..d11842fc1 100644
--- a/command/agent/agent_endpoint_test.go
+++ b/command/agent/agent_endpoint_test.go
@@ -526,9 +526,9 @@ func TestHTTPAgentUpdateCheck(t *testing.T) {
 	}
 
 	cases := []checkUpdate{
-		checkUpdate{"passing", "hello-passing"},
-		checkUpdate{"critical", "hello-critical"},
-		checkUpdate{"warning", "hello-warning"},
+		checkUpdate{structs.HealthPassing, "hello-passing"},
+		checkUpdate{structs.HealthCritical, "hello-critical"},
+		checkUpdate{structs.HealthWarning, "hello-warning"},
 	}
 
 	for _, c := range cases {
@@ -564,7 +564,7 @@ func TestHTTPAgentUpdateCheck(t *testing.T) {
 		}
 
 		update := checkUpdate{
-			Status: "passing",
+			Status: structs.HealthPassing,
 			Output: strings.Repeat("-= bad -=", 5*CheckBufSize),
 		}
 		req.Body = encodeReq(update)
@@ -623,7 +623,7 @@ func TestHTTPAgentUpdateCheck(t *testing.T) {
 		}
 
 		update := checkUpdate{
-			Status: "passing",
+			Status: structs.HealthPassing,
 		}
 		req.Body = encodeReq(update)
 
diff --git a/command/agent/check_test.go b/command/agent/check_test.go
index 053eb5148..e327be32d 100644
--- a/command/agent/check_test.go
+++ b/command/agent/check_test.go
@@ -235,25 +235,25 @@ func TestCheckHTTPCritical(t *testing.T) {
 
 	server := mockHTTPServer(150)
 	fmt.Println(server.URL)
-	expectHTTPStatus(t, server.URL, "critical")
+	expectHTTPStatus(t, server.URL, structs.HealthCritical)
 	server.Close()
 
 	// 2xx - 1
 	server = mockHTTPServer(199)
-	expectHTTPStatus(t, server.URL, "critical")
+	expectHTTPStatus(t, server.URL, structs.HealthCritical)
 	server.Close()
 
 	// 2xx + 1
 	server = mockHTTPServer(300)
-	expectHTTPStatus(t, server.URL, "critical")
+	expectHTTPStatus(t, server.URL, structs.HealthCritical)
 	server.Close()
 
 	server = mockHTTPServer(400)
-	expectHTTPStatus(t, server.URL, "critical")
+	expectHTTPStatus(t, server.URL, structs.HealthCritical)
 	server.Close()
 
 	server = mockHTTPServer(500)
-	expectHTTPStatus(t, server.URL, "critical")
+	expectHTTPStatus(t, server.URL, structs.HealthCritical)
 	server.Close()
 }
 
@@ -261,25 +261,25 @@ func TestCheckHTTPPassing(t *testing.T) {
 	var server *httptest.Server
 
 	server = mockHTTPServer(200)
-	expectHTTPStatus(t, server.URL, "passing")
+	expectHTTPStatus(t, server.URL, structs.HealthPassing)
 	server.Close()
 
 	server = mockHTTPServer(201)
-	expectHTTPStatus(t, server.URL, "passing")
+	expectHTTPStatus(t, server.URL, structs.HealthPassing)
 	server.Close()
 
 	server = mockHTTPServer(250)
-	expectHTTPStatus(t, server.URL, "passing")
+	expectHTTPStatus(t, server.URL, structs.HealthPassing)
 	server.Close()
 
 	server = mockHTTPServer(299)
-	expectHTTPStatus(t, server.URL, "passing")
+	expectHTTPStatus(t, server.URL, structs.HealthPassing)
 	server.Close()
 }
 
 func TestCheckHTTPWarning(t *testing.T) {
 	server := mockHTTPServer(429)
-	expectHTTPStatus(t, server.URL, "warning")
+	expectHTTPStatus(t, server.URL, structs.HealthWarning)
 	server.Close()
 }
 
@@ -323,7 +323,7 @@ func TestCheckHTTPTimeout(t *testing.T) {
 		t.Fatalf("should have at least 2 updates %v", mock.updates)
 	}
 
-	if mock.state["bar"] != "critical" {
+	if mock.state["bar"] != structs.HealthCritical {
 		t.Fatalf("should be critical %v", mock.state)
 	}
 }
@@ -397,7 +397,7 @@ func TestCheckTCPCritical(t *testing.T) {
 	)
 
 	tcpServer = mockTCPServer(`tcp`)
-	expectTCPStatus(t, `127.0.0.1:0`, "critical")
+	expectTCPStatus(t, `127.0.0.1:0`, structs.HealthCritical)
 	tcpServer.Close()
 }
 
@@ -407,11 +407,11 @@ func TestCheckTCPPassing(t *testing.T) {
 	)
 
 	tcpServer = mockTCPServer(`tcp`)
-	expectTCPStatus(t, tcpServer.Addr().String(), "passing")
+	expectTCPStatus(t, tcpServer.Addr().String(), structs.HealthPassing)
 	tcpServer.Close()
 
 	tcpServer = mockTCPServer(`tcp6`)
-	expectTCPStatus(t, tcpServer.Addr().String(), "passing")
+	expectTCPStatus(t, tcpServer.Addr().String(), structs.HealthPassing)
 	tcpServer.Close()
 }
 
@@ -579,27 +579,27 @@ func expectDockerCheckStatus(t *testing.T, dockerClient DockerClient, status str
 }
 
 func TestDockerCheckWhenExecReturnsSuccessExitCode(t *testing.T) {
-	expectDockerCheckStatus(t, &fakeDockerClientWithNoErrors{}, "passing", "output")
+	expectDockerCheckStatus(t, &fakeDockerClientWithNoErrors{}, structs.HealthPassing, "output")
 }
 
 func TestDockerCheckWhenExecCreationFails(t *testing.T) {
-	expectDockerCheckStatus(t, &fakeDockerClientWithCreateExecFailure{}, "critical", "Unable to create Exec, error: Exec Creation Failed")
+	expectDockerCheckStatus(t, &fakeDockerClientWithCreateExecFailure{}, structs.HealthCritical, "Unable to create Exec, error: Exec Creation Failed")
 }
 
 func TestDockerCheckWhenExitCodeIsNonZero(t *testing.T) {
-	expectDockerCheckStatus(t, &fakeDockerClientWithExecNonZeroExitCode{}, "critical", "")
+	expectDockerCheckStatus(t, &fakeDockerClientWithExecNonZeroExitCode{}, structs.HealthCritical, "")
 }
 
 func TestDockerCheckWhenExitCodeIsone(t *testing.T) {
-	expectDockerCheckStatus(t, &fakeDockerClientWithExecExitCodeOne{}, "warning", "output")
+	expectDockerCheckStatus(t, &fakeDockerClientWithExecExitCodeOne{}, structs.HealthWarning, "output")
 }
 
 func TestDockerCheckWhenExecStartFails(t *testing.T) {
-	expectDockerCheckStatus(t, &fakeDockerClientWithStartExecFailure{}, "critical", "Unable to start Exec: Couldn't Start Exec")
+	expectDockerCheckStatus(t, &fakeDockerClientWithStartExecFailure{}, structs.HealthCritical, "Unable to start Exec: Couldn't Start Exec")
 }
 
 func TestDockerCheckWhenExecInfoFails(t *testing.T) {
-	expectDockerCheckStatus(t, &fakeDockerClientWithExecInfoErrors{}, "critical", "Unable to inspect Exec: Unable to query exec info")
+	expectDockerCheckStatus(t, &fakeDockerClientWithExecInfoErrors{}, structs.HealthCritical, "Unable to inspect Exec: Unable to query exec info")
 }
 
 func TestDockerCheckDefaultToSh(t *testing.T) {
diff --git a/command/agent/health_endpoint.go b/command/agent/health_endpoint.go
index e4a36f6a6..b252a4126 100644
--- a/command/agent/health_endpoint.go
+++ b/command/agent/health_endpoint.go
@@ -1,9 +1,10 @@
 package agent
 
 import (
-	"github.com/hashicorp/consul/consul/structs"
 	"net/http"
 	"strings"
+
+	"github.com/hashicorp/consul/consul/structs"
 )
 
 func (s *HTTPServer) HealthChecksInState(resp http.ResponseWriter, req *http.Request) (interface{}, error) {
@@ -126,7 +127,7 @@ func (s *HTTPServer) HealthServiceNodes(resp http.ResponseWriter, req *http.Requ
 	}
 
 	// Filter to only passing if specified
-	if _, ok := params["passing"]; ok {
+	if _, ok := params[structs.HealthPassing]; ok {
 		out.Nodes = filterNonPassing(out.Nodes)
 	}
 
diff --git a/testutil/README.md b/testutil/README.md
index ebbbade5d..d47e76788 100644
--- a/testutil/README.md
+++ b/testutil/README.md
@@ -48,13 +48,13 @@ func TestMain(t *testing.T) {
 	})
 
 	// Create a service
-	srv1.AddService("redis", "passing", []string{"master"})
+	srv1.AddService("redis", structs.HealthPassing, []string{"master"})
 
 	// Create a service check
-	srv1.AddCheck("service:redis", "redis", "passing")
+	srv1.AddCheck("service:redis", "redis", structs.HealthPassing)
 
 	// Create a node check
-	srv1.AddCheck("mem", "", "critical")
+	srv1.AddCheck("mem", "", structs.HealthCritical)
 
 	// The HTTPAddr field contains the address of the Consul
 	// API on the new test server instance.
diff --git a/testutil/server.go b/testutil/server.go
index 5574f668c..8a88a8b1c 100644
--- a/testutil/server.go
+++ b/testutil/server.go
@@ -25,6 +25,7 @@ import (
 	"strings"
 	"sync/atomic"
 
+	"github.com/hashicorp/consul/consul/structs"
 	"github.com/hashicorp/go-cleanhttp"
 )
 
@@ -444,11 +445,11 @@ func (s *TestServer) AddService(name, status string, tags []string) {
 	s.put("/v1/agent/check/register", payload)
 
 	switch status {
-	case "passing":
+	case structs.HealthPassing:
 		s.put("/v1/agent/check/pass/"+chkName, nil)
-	case "warning":
+	case structs.HealthWarning:
 		s.put("/v1/agent/check/warn/"+chkName, nil)
-	case "critical":
+	case structs.HealthCritical:
 		s.put("/v1/agent/check/fail/"+chkName, nil)
 	default:
 		s.t.Fatalf("Unrecognized status: %s", status)
@@ -472,11 +473,11 @@ func (s *TestServer) AddCheck(name, serviceID, status string) {
 	s.put("/v1/agent/check/register", payload)
 
 	switch status {
-	case "passing":
+	case structs.HealthPassing:
 		s.put("/v1/agent/check/pass/"+name, nil)
-	case "warning":
+	case structs.HealthWarning:
 		s.put("/v1/agent/check/warn/"+name, nil)
-	case "critical":
+	case structs.HealthCritical:
 		s.put("/v1/agent/check/fail/"+name, nil)
 	default:
 		s.t.Fatalf("Unrecognized status: %s", status)
diff --git a/watch/funcs_test.go b/watch/funcs_test.go
index 2e0e345a5..78f93c90a 100644
--- a/watch/funcs_test.go
+++ b/watch/funcs_test.go
@@ -6,6 +6,7 @@ import (
 	"time"
 
 	consulapi "github.com/hashicorp/consul/api"
+	"github.com/hashicorp/consul/consul/structs"
 )
 
 var consulAddr string
@@ -299,7 +300,7 @@ func TestChecksWatch_State(t *testing.T) {
 				Node:    "foobar",
 				CheckID: "foobar",
 				Name:    "foobar",
-				Status:  "warning",
+				Status:  structs.HealthWarning,
 			},
 		}
 		catalog.Register(reg, nil)
@@ -363,7 +364,7 @@ func TestChecksWatch_Service(t *testing.T) {
 				Node:      "foobar",
 				CheckID:   "foobar",
 				Name:      "foobar",
-				Status:    "passing",
+				Status:    structs.HealthPassing,
 				ServiceID: "foobar",
 			},
 		}