diff --git a/akka-docs-dev/rst/java/stream-integrations.rst b/akka-docs-dev/rst/java/stream-integrations.rst
index 8389fdc6b4..eaa5519886 100644
--- a/akka-docs-dev/rst/java/stream-integrations.rst
+++ b/akka-docs-dev/rst/java/stream-integrations.rst
@@ -37,7 +37,9 @@ stream if there is demand from downstream, otherwise they will be buffered until
 demand is received.
 
 Depending on the defined :class:`OverflowStrategy` it might drop elements if there is no space
-available in the buffer.
+available in the buffer. The strategy :class:`OverflowStrategy.backpressure()` is not supported
+for this Source type, you should consider using ActorPublisher if you want a backpressured
+actor interface.
 
 The stream can be completed successfully by sending ``akka.actor.PoisonPill`` or
 ``akka.actor.Status.Success`` to the actor reference.
diff --git a/akka-docs-dev/rst/scala/stream-integrations.rst b/akka-docs-dev/rst/scala/stream-integrations.rst
index 01e97a5d8a..a0c086bd2c 100644
--- a/akka-docs-dev/rst/scala/stream-integrations.rst
+++ b/akka-docs-dev/rst/scala/stream-integrations.rst
@@ -32,7 +32,9 @@ stream if there is demand from downstream, otherwise they will be buffered until
 demand is received.
 
 Depending on the defined :class:`OverflowStrategy` it might drop elements if there is no space
-available in the buffer.
+available in the buffer. The strategy :class:`OverflowStrategy.backpressure` is not supported
+for this Source type, you should consider using ActorPublisher if you want a backpressured
+actor interface.
 
 The stream can be completed successfully by sending ``akka.actor.PoisonPill`` or
 ``akka.actor.Status.Success`` to the actor reference.
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
index 1cbf51ef5c..9035230538 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
@@ -186,6 +186,9 @@ object Source {
    * Depending on the defined [[akka.stream.OverflowStrategy]] it might drop elements if
    * there is no space available in the buffer.
    *
+   * The strategy [[akka.stream.OverflowStrategy.backpressure]] is not supported, and an
+   * IllegalArgument("Backpressure overflowStrategy not supported") will be thrown if it is passed as argument.
+   *
    * The buffer can be disabled by using `bufferSize` of 0 and then received messages are dropped
    * if there is no demand from downstream. When `bufferSize` is 0 the `overflowStrategy` does
    * not matter.
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
index ee1ffbfd16..5782e738c0 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
@@ -324,6 +324,9 @@ object Source extends SourceApply {
    * Depending on the defined [[akka.stream.OverflowStrategy]] it might drop elements if
    * there is no space available in the buffer.
    *
+   * The strategy [[akka.stream.OverflowStrategy.backpressure]] is not supported, and an
+   * IllegalArgument("Backpressure overflowStrategy not supported") will be thrown if it is passed as argument.
+   *
    * The buffer can be disabled by using `bufferSize` of 0 and then received messages are dropped
    * if there is no demand from downstream. When `bufferSize` is 0 the `overflowStrategy` does
    * not matter.