diff --git a/TimeSeries/PublicApis/SdkExamples/WaterWatchPreProcessor/Dtos/SavedState.cs b/TimeSeries/PublicApis/SdkExamples/WaterWatchPreProcessor/Dtos/SavedState.cs
index 9c42d3d1..253c5111 100644
--- a/TimeSeries/PublicApis/SdkExamples/WaterWatchPreProcessor/Dtos/SavedState.cs
+++ b/TimeSeries/PublicApis/SdkExamples/WaterWatchPreProcessor/Dtos/SavedState.cs
@@ -5,7 +5,7 @@ namespace WaterWatchPreProcessor.Dtos
 {
     public class SavedState
     {
-        public Dictionary<string, DateTime> LastSeenBySensorSerial { get; set; } =
+        public Dictionary<string, DateTime> NextMeasurementTimeBySensorSerial { get; set; } =
             new Dictionary<string, DateTime>(StringComparer.InvariantCultureIgnoreCase);
     }
 }
diff --git a/TimeSeries/PublicApis/SdkExamples/WaterWatchPreProcessor/Exporter.cs b/TimeSeries/PublicApis/SdkExamples/WaterWatchPreProcessor/Exporter.cs
index 521c9276..f563dfef 100644
--- a/TimeSeries/PublicApis/SdkExamples/WaterWatchPreProcessor/Exporter.cs
+++ b/TimeSeries/PublicApis/SdkExamples/WaterWatchPreProcessor/Exporter.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using ServiceStack;
 using ServiceStack.Text;
 using WaterWatchPreProcessor.Dtos;
@@ -28,18 +29,28 @@ public void Run()
             var nameFilter = new Filter<RegexFilter>(Context.SensorNameFilters);
             var serialFilter = new Filter<RegexFilter>(Context.SensorSerialFilters);
 
+            Console.WriteLine("Iso8601UtcTime, SensorType, SensorSerial, Value");
+
             foreach (var sensor in sensors)
             {
                 if (nameFilter.IsFiltered(f => f.Regex.IsMatch(sensor.Name))
                     || serialFilter.IsFiltered(f => f.Regex.IsMatch(sensor.Serial)))
                     continue;
 
-                foreach (var measurement in GetSensorMeasurements(sensor))
+                var measurements = GetSensorMeasurements(sensor)
+                    .ToList();
+
+                var latestMeasurement = measurements.LastOrDefault();
+
+                if (latestMeasurement != null)
                 {
-                    Console.WriteLine($"{measurement.Time:yyyy-MM-ddTHH:mm:ss.fffZ}, {sensor.SensorType}, {sensor.Serial}, {GetSensorValue(sensor, measurement.RawDistance)}");
+                    SavedState.NextMeasurementTimeBySensorSerial[sensor.Serial] = latestMeasurement.Time.AddMilliseconds(1);
                 }
 
-                SavedState.LastSeenBySensorSerial[sensor.Serial] = sensor.LatestData.LastSeen;
+                foreach (var measurement in measurements)
+                {
+                    Console.WriteLine($"{measurement.Time:yyyy-MM-ddTHH:mm:ss.fffZ}, {sensor.SensorType}, {sensor.Serial}, {GetSensorValue(sensor, measurement.RawDistance)}");
+                }
             }
 
             PersistSavedState();
@@ -78,7 +89,7 @@ private IList<Sensor> GetSensors()
 
         private IEnumerable<Measurement> GetSensorMeasurements(Sensor sensor)
         {
-            if (!SavedState.LastSeenBySensorSerial.TryGetValue(sensor.Serial, out var lastSeenTime))
+            if (!SavedState.NextMeasurementTimeBySensorSerial.TryGetValue(sensor.Serial, out var lastSeenTime))
             {
                 lastSeenTime = DateTime.UtcNow.Date.AddDays(-Context.NewSensorSyncDays);
             }
diff --git a/TimeSeries/PublicApis/SdkExamples/WaterWatchPreProcessor/Readme.md b/TimeSeries/PublicApis/SdkExamples/WaterWatchPreProcessor/Readme.md
index dcea4715..a646b568 100644
--- a/TimeSeries/PublicApis/SdkExamples/WaterWatchPreProcessor/Readme.md
+++ b/TimeSeries/PublicApis/SdkExamples/WaterWatchPreProcessor/Readme.md
@@ -59,14 +59,12 @@ Use `/OutputMode=RawDistance` to always show the sensor's rawDistance value.
 
 Each time the tool runs, it queries the WatchWatch API for any new measurements.
 
-`Iso8601UtcTime, SensorType, SensorSerial, Value`
-
 Each new measurement will be output to standard out as the following CSV stream:
 
-
 ```csv
+Iso8601UtcTime, SensorType, SensorSerial, Value
 2018-12-31T14:35:00.000Z, LS1, 418892, 92.23456
-2018-12-31T15:35:00.000Z, LS1, 418892, 89.47586
+2018-12-31T14:37:00.000Z, LS1, 40AD1C, 289.47586
 ```
 
 ## `/help` screen