diff --git a/services/src/generated/main/grpc/io/grpc/health/v1/HealthGrpc.java b/services/src/generated/main/grpc/io/grpc/health/v1/HealthGrpc.java
index 295a747fc9..4a4f9fba78 100644
--- a/services/src/generated/main/grpc/io/grpc/health/v1/HealthGrpc.java
+++ b/services/src/generated/main/grpc/io/grpc/health/v1/HealthGrpc.java
@@ -59,6 +59,38 @@ public final class HealthGrpc {
      return getCheckMethod;
   }
 
+  private static volatile io.grpc.MethodDescriptor<io.grpc.health.v1.HealthCheckRequest,
+      io.grpc.health.v1.HealthCheckResponse> getWatchMethod;
+
+  @io.grpc.stub.annotations.RpcMethod(
+      fullMethodName = SERVICE_NAME + '/' + "Watch",
+      requestType = io.grpc.health.v1.HealthCheckRequest.class,
+      responseType = io.grpc.health.v1.HealthCheckResponse.class,
+      methodType = io.grpc.MethodDescriptor.MethodType.SERVER_STREAMING)
+  public static io.grpc.MethodDescriptor<io.grpc.health.v1.HealthCheckRequest,
+      io.grpc.health.v1.HealthCheckResponse> getWatchMethod() {
+    io.grpc.MethodDescriptor<io.grpc.health.v1.HealthCheckRequest, io.grpc.health.v1.HealthCheckResponse> getWatchMethod;
+    if ((getWatchMethod = HealthGrpc.getWatchMethod) == null) {
+      synchronized (HealthGrpc.class) {
+        if ((getWatchMethod = HealthGrpc.getWatchMethod) == null) {
+          HealthGrpc.getWatchMethod = getWatchMethod = 
+              io.grpc.MethodDescriptor.<io.grpc.health.v1.HealthCheckRequest, io.grpc.health.v1.HealthCheckResponse>newBuilder()
+              .setType(io.grpc.MethodDescriptor.MethodType.SERVER_STREAMING)
+              .setFullMethodName(generateFullMethodName(
+                  "grpc.health.v1.Health", "Watch"))
+              .setSampledToLocalTracing(true)
+              .setRequestMarshaller(io.grpc.protobuf.ProtoUtils.marshaller(
+                  io.grpc.health.v1.HealthCheckRequest.getDefaultInstance()))
+              .setResponseMarshaller(io.grpc.protobuf.ProtoUtils.marshaller(
+                  io.grpc.health.v1.HealthCheckResponse.getDefaultInstance()))
+                  .setSchemaDescriptor(new HealthMethodDescriptorSupplier("Watch"))
+                  .build();
+          }
+        }
+     }
+     return getWatchMethod;
+  }
+
   /**
    * Creates a new async stub that supports all call types for the service
    */
@@ -87,12 +119,38 @@ public final class HealthGrpc {
   public static abstract class HealthImplBase implements io.grpc.BindableService {
 
     /**
+     * <pre>
+     * If the requested service is unknown, the call will fail with status
+     * NOT_FOUND.
+     * </pre>
      */
     public void check(io.grpc.health.v1.HealthCheckRequest request,
         io.grpc.stub.StreamObserver<io.grpc.health.v1.HealthCheckResponse> responseObserver) {
       asyncUnimplementedUnaryCall(getCheckMethod(), responseObserver);
     }
 
+    /**
+     * <pre>
+     * Performs a watch for the serving status of the requested service.
+     * The server will immediately send back a message indicating the current
+     * serving status.  It will then subsequently send a new message whenever
+     * the service's serving status changes.
+     * If the requested service is unknown when the call is received, the
+     * server will send a message setting the serving status to
+     * SERVICE_UNKNOWN but will *not* terminate the call.  If at some
+     * future point, the serving status of the service becomes known, the
+     * server will send a new message with the service's serving status.
+     * If the call terminates with status UNIMPLEMENTED, then clients
+     * should assume this method is not supported and should not retry the
+     * call.  If the call terminates with any other status (including OK),
+     * clients should retry the call with appropriate exponential backoff.
+     * </pre>
+     */
+    public void watch(io.grpc.health.v1.HealthCheckRequest request,
+        io.grpc.stub.StreamObserver<io.grpc.health.v1.HealthCheckResponse> responseObserver) {
+      asyncUnimplementedUnaryCall(getWatchMethod(), responseObserver);
+    }
+
     @java.lang.Override public final io.grpc.ServerServiceDefinition bindService() {
       return io.grpc.ServerServiceDefinition.builder(getServiceDescriptor())
           .addMethod(
@@ -102,6 +160,13 @@ public final class HealthGrpc {
                 io.grpc.health.v1.HealthCheckRequest,
                 io.grpc.health.v1.HealthCheckResponse>(
                   this, METHODID_CHECK)))
+          .addMethod(
+            getWatchMethod(),
+            asyncServerStreamingCall(
+              new MethodHandlers<
+                io.grpc.health.v1.HealthCheckRequest,
+                io.grpc.health.v1.HealthCheckResponse>(
+                  this, METHODID_WATCH)))
           .build();
     }
   }
@@ -125,12 +190,39 @@ public final class HealthGrpc {
     }
 
     /**
+     * <pre>
+     * If the requested service is unknown, the call will fail with status
+     * NOT_FOUND.
+     * </pre>
      */
     public void check(io.grpc.health.v1.HealthCheckRequest request,
         io.grpc.stub.StreamObserver<io.grpc.health.v1.HealthCheckResponse> responseObserver) {
       asyncUnaryCall(
           getChannel().newCall(getCheckMethod(), getCallOptions()), request, responseObserver);
     }
+
+    /**
+     * <pre>
+     * Performs a watch for the serving status of the requested service.
+     * The server will immediately send back a message indicating the current
+     * serving status.  It will then subsequently send a new message whenever
+     * the service's serving status changes.
+     * If the requested service is unknown when the call is received, the
+     * server will send a message setting the serving status to
+     * SERVICE_UNKNOWN but will *not* terminate the call.  If at some
+     * future point, the serving status of the service becomes known, the
+     * server will send a new message with the service's serving status.
+     * If the call terminates with status UNIMPLEMENTED, then clients
+     * should assume this method is not supported and should not retry the
+     * call.  If the call terminates with any other status (including OK),
+     * clients should retry the call with appropriate exponential backoff.
+     * </pre>
+     */
+    public void watch(io.grpc.health.v1.HealthCheckRequest request,
+        io.grpc.stub.StreamObserver<io.grpc.health.v1.HealthCheckResponse> responseObserver) {
+      asyncServerStreamingCall(
+          getChannel().newCall(getWatchMethod(), getCallOptions()), request, responseObserver);
+    }
   }
 
   /**
@@ -152,11 +244,38 @@ public final class HealthGrpc {
     }
 
     /**
+     * <pre>
+     * If the requested service is unknown, the call will fail with status
+     * NOT_FOUND.
+     * </pre>
      */
     public io.grpc.health.v1.HealthCheckResponse check(io.grpc.health.v1.HealthCheckRequest request) {
       return blockingUnaryCall(
           getChannel(), getCheckMethod(), getCallOptions(), request);
     }
+
+    /**
+     * <pre>
+     * Performs a watch for the serving status of the requested service.
+     * The server will immediately send back a message indicating the current
+     * serving status.  It will then subsequently send a new message whenever
+     * the service's serving status changes.
+     * If the requested service is unknown when the call is received, the
+     * server will send a message setting the serving status to
+     * SERVICE_UNKNOWN but will *not* terminate the call.  If at some
+     * future point, the serving status of the service becomes known, the
+     * server will send a new message with the service's serving status.
+     * If the call terminates with status UNIMPLEMENTED, then clients
+     * should assume this method is not supported and should not retry the
+     * call.  If the call terminates with any other status (including OK),
+     * clients should retry the call with appropriate exponential backoff.
+     * </pre>
+     */
+    public java.util.Iterator<io.grpc.health.v1.HealthCheckResponse> watch(
+        io.grpc.health.v1.HealthCheckRequest request) {
+      return blockingServerStreamingCall(
+          getChannel(), getWatchMethod(), getCallOptions(), request);
+    }
   }
 
   /**
@@ -178,6 +297,10 @@ public final class HealthGrpc {
     }
 
     /**
+     * <pre>
+     * If the requested service is unknown, the call will fail with status
+     * NOT_FOUND.
+     * </pre>
      */
     public com.google.common.util.concurrent.ListenableFuture<io.grpc.health.v1.HealthCheckResponse> check(
         io.grpc.health.v1.HealthCheckRequest request) {
@@ -187,6 +310,7 @@ public final class HealthGrpc {
   }
 
   private static final int METHODID_CHECK = 0;
+  private static final int METHODID_WATCH = 1;
 
   private static final class MethodHandlers<Req, Resp> implements
       io.grpc.stub.ServerCalls.UnaryMethod<Req, Resp>,
@@ -209,6 +333,10 @@ public final class HealthGrpc {
           serviceImpl.check((io.grpc.health.v1.HealthCheckRequest) request,
               (io.grpc.stub.StreamObserver<io.grpc.health.v1.HealthCheckResponse>) responseObserver);
           break;
+        case METHODID_WATCH:
+          serviceImpl.watch((io.grpc.health.v1.HealthCheckRequest) request,
+              (io.grpc.stub.StreamObserver<io.grpc.health.v1.HealthCheckResponse>) responseObserver);
+          break;
         default:
           throw new AssertionError();
       }
@@ -271,6 +399,7 @@ public final class HealthGrpc {
           serviceDescriptor = result = io.grpc.ServiceDescriptor.newBuilder(SERVICE_NAME)
               .setSchemaDescriptor(new HealthFileDescriptorSupplier())
               .addMethod(getCheckMethod())
+              .addMethod(getWatchMethod())
               .build();
         }
       }
diff --git a/services/src/generated/main/java/io/grpc/health/v1/HealthCheckResponse.java b/services/src/generated/main/java/io/grpc/health/v1/HealthCheckResponse.java
index efe312cad9..cfb969b493 100644
--- a/services/src/generated/main/java/io/grpc/health/v1/HealthCheckResponse.java
+++ b/services/src/generated/main/java/io/grpc/health/v1/HealthCheckResponse.java
@@ -97,6 +97,14 @@ private static final long serialVersionUID = 0L;
      * <code>NOT_SERVING = 2;</code>
      */
     NOT_SERVING(2),
+    /**
+     * <pre>
+     * Used only by the Watch method.
+     * </pre>
+     *
+     * <code>SERVICE_UNKNOWN = 3;</code>
+     */
+    SERVICE_UNKNOWN(3),
     UNRECOGNIZED(-1),
     ;
 
@@ -112,6 +120,14 @@ private static final long serialVersionUID = 0L;
      * <code>NOT_SERVING = 2;</code>
      */
     public static final int NOT_SERVING_VALUE = 2;
+    /**
+     * <pre>
+     * Used only by the Watch method.
+     * </pre>
+     *
+     * <code>SERVICE_UNKNOWN = 3;</code>
+     */
+    public static final int SERVICE_UNKNOWN_VALUE = 3;
 
 
     public final int getNumber() {
@@ -135,6 +151,7 @@ private static final long serialVersionUID = 0L;
         case 0: return UNKNOWN;
         case 1: return SERVING;
         case 2: return NOT_SERVING;
+        case 3: return SERVICE_UNKNOWN;
         default: return null;
       }
     }
diff --git a/services/src/generated/main/java/io/grpc/health/v1/HealthProto.java b/services/src/generated/main/java/io/grpc/health/v1/HealthProto.java
index ce0d1bde10..8329cbea52 100644
--- a/services/src/generated/main/java/io/grpc/health/v1/HealthProto.java
+++ b/services/src/generated/main/java/io/grpc/health/v1/HealthProto.java
@@ -35,14 +35,18 @@ public final class HealthProto {
     java.lang.String[] descriptorData = {
       "\n\033grpc/health/v1/health.proto\022\016grpc.heal" +
       "th.v1\"%\n\022HealthCheckRequest\022\017\n\007service\030\001" +
-      " \001(\t\"\224\001\n\023HealthCheckResponse\022A\n\006status\030\001" +
+      " \001(\t\"\251\001\n\023HealthCheckResponse\022A\n\006status\030\001" +
       " \001(\01621.grpc.health.v1.HealthCheckRespons" +
-      "e.ServingStatus\":\n\rServingStatus\022\013\n\007UNKN" +
-      "OWN\020\000\022\013\n\007SERVING\020\001\022\017\n\013NOT_SERVING\020\0022Z\n\006H" +
-      "ealth\022P\n\005Check\022\".grpc.health.v1.HealthCh" +
-      "eckRequest\032#.grpc.health.v1.HealthCheckR" +
-      "esponseB3\n\021io.grpc.health.v1B\013HealthProt" +
-      "oP\001\252\002\016Grpc.Health.V1b\006proto3"
+      "e.ServingStatus\"O\n\rServingStatus\022\013\n\007UNKN" +
+      "OWN\020\000\022\013\n\007SERVING\020\001\022\017\n\013NOT_SERVING\020\002\022\023\n\017S" +
+      "ERVICE_UNKNOWN\020\0032\256\001\n\006Health\022P\n\005Check\022\".g" +
+      "rpc.health.v1.HealthCheckRequest\032#.grpc." +
+      "health.v1.HealthCheckResponse\022R\n\005Watch\022\"" +
+      ".grpc.health.v1.HealthCheckRequest\032#.grp" +
+      "c.health.v1.HealthCheckResponse0\001Ba\n\021io." +
+      "grpc.health.v1B\013HealthProtoP\001Z,google.go" +
+      "lang.org/grpc/health/grpc_health_v1\252\002\016Gr" +
+      "pc.Health.V1b\006proto3"
     };
     com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner assigner =
         new com.google.protobuf.Descriptors.FileDescriptor.    InternalDescriptorAssigner() {
diff --git a/services/src/main/proto/grpc/health/v1/health.proto b/services/src/main/proto/grpc/health/v1/health.proto
index 44c443230d..38843ff1e7 100644
--- a/services/src/main/proto/grpc/health/v1/health.proto
+++ b/services/src/main/proto/grpc/health/v1/health.proto
@@ -12,11 +12,15 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// The canonical version of this proto can be found at
+// https://github.com/grpc/grpc-proto/blob/master/grpc/health/v1/health.proto
+
 syntax = "proto3";
 
 package grpc.health.v1;
 
 option csharp_namespace = "Grpc.Health.V1";
+option go_package = "google.golang.org/grpc/health/grpc_health_v1";
 option java_multiple_files = true;
 option java_outer_classname = "HealthProto";
 option java_package = "io.grpc.health.v1";
@@ -30,10 +34,30 @@ message HealthCheckResponse {
     UNKNOWN = 0;
     SERVING = 1;
     NOT_SERVING = 2;
+    SERVICE_UNKNOWN = 3;  // Used only by the Watch method.
   }
   ServingStatus status = 1;
 }
 
 service Health {
+  // If the requested service is unknown, the call will fail with status
+  // NOT_FOUND.
   rpc Check(HealthCheckRequest) returns (HealthCheckResponse);
+
+  // Performs a watch for the serving status of the requested service.
+  // The server will immediately send back a message indicating the current
+  // serving status.  It will then subsequently send a new message whenever
+  // the service's serving status changes.
+  //
+  // If the requested service is unknown when the call is received, the
+  // server will send a message setting the serving status to
+  // SERVICE_UNKNOWN but will *not* terminate the call.  If at some
+  // future point, the serving status of the service becomes known, the
+  // server will send a new message with the service's serving status.
+  //
+  // If the call terminates with status UNIMPLEMENTED, then clients
+  // should assume this method is not supported and should not retry the
+  // call.  If the call terminates with any other status (including OK),
+  // clients should retry the call with appropriate exponential backoff.
+  rpc Watch(HealthCheckRequest) returns (stream HealthCheckResponse);
 }