diff --git a/layers/transportation_name/layer.sql b/layers/transportation_name/layer.sql
index 2d68bff..7d11ce2 100644
--- a/layers/transportation_name/layer.sql
+++ b/layers/transportation_name/layer.sql
@@ -1,4 +1,3 @@
-
 -- etldoc: layer_transportation_name[shape=record fillcolor=lightpink, style="rounded,filled",
 -- etldoc:     label="layer_transportation_name | <z8> z8 |<z9> z9 |<z10> z10 |<z11> z11 |<z12> z12|<z13> z13|<z14_> z14+" ] ;
 
diff --git a/layers/transportation_name/merge_highways.sql b/layers/transportation_name/merge_highways.sql
index 6a58c99..e0ca248 100644
--- a/layers/transportation_name/merge_highways.sql
+++ b/layers/transportation_name/merge_highways.sql
@@ -1,3 +1,8 @@
+DROP TABLE IF EXISTS osm_transportation_name_linestring;
+DROP TABLE IF EXISTS osm_transportation_name_linestring_gen1;
+DROP TABLE IF EXISTS osm_transportation_name_linestring_gen2;
+DROP TABLE IF EXISTS osm_transportation_name_linestring_gen3;
+
 -- Instead of using relations to find out the road names we
 -- stitch together the touching ways with the same name
 -- to allow for nice label rendering
diff --git a/layers/water_name/water_lakeline.sql b/layers/water_name/water_lakeline.sql
index 20381ef..2593a27 100644
--- a/layers/water_name/water_lakeline.sql
+++ b/layers/water_name/water_lakeline.sql
@@ -1,3 +1,5 @@
+DROP TABLE IF EXISTS osm_water_lakeline;
+
 -- etldoc:  osm_water_polygon ->  osm_water_lakeline
 -- etldoc:  lake_centerline  ->  osm_water_lakeline
 CREATE TABLE IF NOT EXISTS osm_water_lakeline AS (
diff --git a/layers/water_name/water_point.sql b/layers/water_name/water_point.sql
index 5f9658a..54b5b45 100644
--- a/layers/water_name/water_point.sql
+++ b/layers/water_name/water_point.sql
@@ -1,3 +1,5 @@
+DROP TABLE IF EXISTS osm_water_point;
+
 -- etldoc:  osm_water_polygon ->  osm_water_point
 -- etldoc:  lake_centerline ->  osm_water_point
 CREATE TABLE IF NOT EXISTS osm_water_point AS (
diff --git a/layers/waterway/merge_waterway.sql b/layers/waterway/merge_waterway.sql
index c58b21a..6e2b816 100644
--- a/layers/waterway/merge_waterway.sql
+++ b/layers/waterway/merge_waterway.sql
@@ -1,3 +1,8 @@
+DROP TABLE IF EXISTS osm_important_waterway_linestring;
+DROP TABLE IF EXISTS osm_important_waterway_linestring_gen1;
+DROP TABLE IF EXISTS osm_important_waterway_linestring_gen2;
+DROP TABLE IF EXISTS osm_important_waterway_linestring_gen3;
+
 -- We merge the waterways by name like the highways
 -- This helps to drop not important rivers (since they do not have a name)
 -- and also makes it possible to filter out too short rivers