diff --git a/server/api/flukso/src/flukso.erl b/server/api/flukso/src/flukso.erl
index 7862740..deb9853 100644
--- a/server/api/flukso/src/flukso.erl
+++ b/server/api/flukso/src/flukso.erl
@@ -30,6 +30,7 @@ ensure_started(App) ->
     end.
 
 mysql_prepare() ->
+    mysql:prepare(watchdog, <<"INSERT INTO watchdog (uid, type, message, variables, severity, location, hostname, timestamp) VALUES (?, ?, ?, ?, ?, ?, ?, ?)">>),
     mysql:prepare(permissions, <<"SELECT permissions FROM logger_tokens WHERE meter = ? AND token = ?">>),
     mysql:prepare(device_key, <<"SELECT sha FROM (logger_devices ld INNER JOIN logger_meters lm ON ld.device = lm.device) WHERE lm.meter = ?">>),
     mysql:prepare(sensor_props, <<"SELECT uid, device, night FROM logger_meters WHERE meter = ?">>),
diff --git a/server/api/flukso/src/flukso.hrl b/server/api/flukso/src/flukso.hrl
index 02c08b8..d56aa1f 100644
--- a/server/api/flukso/src/flukso.hrl
+++ b/server/api/flukso/src/flukso.hrl
@@ -165,3 +165,26 @@ time_to_seconds(Time) ->
         false -> false;
         {_Time, TimeSec} -> TimeSec
     end.
+
+% severity levels
+-define(EMERGENCY, 0).
+-define(ALERT,     1).
+-define(CRITICAL,  2).
+-define(ERROR,     3).
+-define(WARNING,   4).
+-define(NOTICE,    5).
+-define(INFO,      6).
+-define(DEBUG,     7).
+
+% log to Drupal's watchdog table
+logger(Uid, Type, Message, Severity, ReqData) ->
+    mysql:execute(pool, watchdog,
+        [Uid,
+         Type,
+         Message,
+         <<"a:0:{}">>,
+         Severity,
+         list_to_binary(wrq:raw_path(ReqData)),
+         list_to_binary(wrq:peer(ReqData)),
+         unix_time()
+        ]).
diff --git a/server/api/flukso/src/flukso_sensor_xyz.erl b/server/api/flukso/src/flukso_sensor_xyz.erl
index 47044e2..841166e 100644
--- a/server/api/flukso/src/flukso_sensor_xyz.erl
+++ b/server/api/flukso/src/flukso_sensor_xyz.erl
@@ -153,17 +153,17 @@ process_post(ReqData, #state{rrdSensor = RrdSensor} = State) ->
     case erlrrd:update([?BASE_PATH, [RrdSensor|".rrd"], " ", RrdData]) of
         {ok, _RrdResponse} ->
             RrdResponse = "ok",
-            NewMidnight = update_night(RrdSensor, Uid, Midnight, LastTimestamp),
+            NewMidnight = update_night(RrdSensor, Uid, Midnight, LastTimestamp, ReqData),
             mysql:execute(pool, sensor_update, [unix_time(), NewMidnight, LastValue, RrdSensor]);
 
         {error, RrdResponse} ->
-            true
+            logger(Uid, <<"rrdupdate.base">>, list_to_binary(RrdResponse), ?ERROR, ReqData)
     end,
 
     JsonResponse = mochijson2:encode({struct, [{<<"response">>, list_to_binary(RrdResponse)}]}),
     {true , wrq:set_resp_body(JsonResponse, ReqData), State}.
 
-update_night(RrdSensor, Uid, Midnight, LastTimestamp) when LastTimestamp > Midnight + 6 * ?HOUR ->
+update_night(RrdSensor, Uid, Midnight, LastTimestamp, ReqData) when LastTimestamp > Midnight + 6 * ?HOUR ->
     LastMidnight = calculate_midnight(unix_time(), Uid),
 
     case erlrrd:fetch(erlrrd:c([[?BASE_PATH, [RrdSensor|".rrd"]], "AVERAGE", ["-s ", integer_to_list(LastMidnight + 2 * ?HOUR)], ["-e ", integer_to_list(LastMidnight + 5 * ?HOUR)], ["-r ", integer_to_list(?QUARTER)]])) of
@@ -175,12 +175,12 @@ update_night(RrdSensor, Uid, Midnight, LastTimestamp) when LastTimestamp > Midni
 %debugging: io:format("~s~n", [[?NIGHT_PATH, [RrdSensor|".rrd"], " ", integer_to_list(LastMidnight + 5 * ?HOUR), ":", float_to_list(NightAverage)]]),
 
             erlrrd:update([?NIGHT_PATH, [RrdSensor|".rrd"], " ", integer_to_list(LastMidnight + 5 * ?HOUR), ":", float_to_list(NightAverage)]);
-        {error, _Reason} ->
-            true
+        {error, Reason} ->
+            logger(Uid, <<"rrdupdate.night">>, list_to_binary(Reason), ?ERROR, ReqData)
     end,
 
     LastMidnight + ?DAY;
-update_night(_RrdSensor, _Uid, Midnight, _LastTimestamp) ->
+update_night(_RrdSensor, _Uid, Midnight, _LastTimestamp, _ReqData) ->
     Midnight.
 
 calculate_midnight(Timestamp, Uid) ->