diff --git a/src/main/scala/BTreeChart.scala b/src/main/scala/BTreeChart.scala
index 881bde3..e86e045 100644
--- a/src/main/scala/BTreeChart.scala
+++ b/src/main/scala/BTreeChart.scala
@@ -87,6 +87,7 @@ case class ChartParameters(width: Int, height: Int, xMin: Long, xMax: Long, yMin
   def xValToPos(value: Long): Double = (value - xMin) * xScale
   def xPosToVal(pos: Double): Long = (pos / xScale).toLong + xMin
   def yValToPos(value: Double): Double = (yMax - value) * yScale
+  def yPosToVal(pos: Double): Double = yMax - (pos / yScale)
 
   // TODO is this the right place for these functions to live?
   def timestampFromDateTime(dateTime: ZonedDateTime): Long = {
diff --git a/src/main/scala/GridCanvas.scala b/src/main/scala/GridCanvas.scala
index 4cb5359..9ac744a 100644
--- a/src/main/scala/GridCanvas.scala
+++ b/src/main/scala/GridCanvas.scala
@@ -38,6 +38,21 @@ class GridCanvas extends ResizableCanvas {
     gc.restore()
   }
 
+
+  protected def drawValueLines(gc: GraphicsContext, scale: ChartParameters): Unit = {
+    gc.save()
+    gc.setStroke(gc.getStroke.asInstanceOf[Color].deriveColor(0, 1, 1, GRIDLINE_ALPHA))
+    gc.setLineWidth(CONTEXT_GRIDLINE_WIDTH)
+    val v_interval = List.range(0,scale.height,64)
+    v_interval.foreach{ value =>
+      gc.strokeLine(0,value,scale.width,value)
+//      println(s"DEBUG: value: $value")
+      RenderHelper.drawContrastText(gc, ChartCommon.CONTRAST_BACKGROUND, ((scale.yPosToVal(value) * 100).round / 100.toDouble).toString,
+        20, value)
+    }
+    gc.restore()
+  }
+
   protected def drawRulers(gc: GraphicsContext, scale: ChartParameters,
                            priorContextTime: ZonedDateTime,
                            tickTimes: Seq[ZonedDateTime], contextTimes: Seq[ZonedDateTime]): Unit = {
@@ -86,6 +101,6 @@ class GridCanvas extends ResizableCanvas {
 
     drawGridlines(gc, scale, tickTimes, contextTimes)
     drawRulers(gc, scale, priorContextTime, tickTimes, contextTimes)
-
+    drawValueLines(gc,scale)
   }
 }