diff --git a/layers/water/README.md b/layers/water/README.md
index 589e71db..b43661bd 100644
--- a/layers/water/README.md
+++ b/layers/water/README.md
@@ -7,5 +7,4 @@ Read the layer documentation at **http://openmaptiles.org/schema#water**
 ![Mapping diagram for water](http://openmaptiles.org/media/mapping_water.png)
 
 ### ETL diagram
-![ETL diagram for water](http://openmaptiles.org/media/etl_water.png)
-
+![ETL diagram for water](etl_diagram.png?raw=true)
diff --git a/layers/water/etl_diagram.png b/layers/water/etl_diagram.png
new file mode 100644
index 00000000..c19e879f
Binary files /dev/null and b/layers/water/etl_diagram.png differ
diff --git a/layers/water/mapping.yaml b/layers/water/mapping.yaml
index d1ba1a55..e44b19ae 100644
--- a/layers/water/mapping.yaml
+++ b/layers/water/mapping.yaml
@@ -1,5 +1,11 @@
 generalized_tables:
 
+  # etldoc: imposm3 -> osm_water_polygon_gen6
+  water_polygon_gen6:
+    source: water_polygon_gen5
+    sql_filter: area>20000000.0
+    tolerance: 640.0
+
   # etldoc: imposm3 -> osm_water_polygon_gen5
   water_polygon_gen5:
     source: water_polygon_gen4
diff --git a/layers/water/water.sql b/layers/water/water.sql
index 450860fd..764f826b 100644
--- a/layers/water/water.sql
+++ b/layers/water/water.sql
@@ -5,66 +5,66 @@ $$ LANGUAGE SQL IMMUTABLE;
 
 
 CREATE OR REPLACE VIEW water_z0 AS (
-    -- etldoc:  ne_110m_ocean ->  water_z0 
+    -- etldoc:  ne_110m_ocean ->  water_z0
     SELECT geometry, 'ocean'::text AS class FROM ne_110m_ocean
     UNION ALL
-    -- etldoc:  ne_110m_lakes ->  water_z0     
+    -- etldoc:  ne_110m_lakes ->  water_z0
     SELECT geometry, 'lake'::text AS class FROM ne_110m_lakes
 );
 
 CREATE OR REPLACE VIEW water_z1 AS (
-    -- etldoc:  ne_110m_ocean ->  water_z1    
+    -- etldoc:  ne_110m_ocean ->  water_z1
     SELECT geometry, 'ocean'::text AS class FROM ne_110m_ocean
     UNION ALL
-    -- etldoc:  ne_110m_lakes ->  water_z1    
+    -- etldoc:  ne_110m_lakes ->  water_z1
     SELECT geometry, 'lake'::text AS class FROM ne_110m_lakes
 );
 
 CREATE OR REPLACE VIEW water_z2 AS (
-    -- etldoc:  ne_50m_ocean ->  water_z2    
+    -- etldoc:  ne_50m_ocean ->  water_z2
     SELECT geometry, 'ocean'::text AS class FROM ne_50m_ocean
     UNION ALL
-    -- etldoc:  ne_50m_lakes ->  water_z2     
+    -- etldoc:  ne_50m_lakes ->  water_z2
     SELECT geometry, 'lake'::text AS class FROM ne_50m_lakes
 );
 
 CREATE OR REPLACE VIEW water_z4 AS (
-    -- etldoc:  ne_50m_ocean ->  water_z4       
+    -- etldoc:  ne_50m_ocean ->  water_z4
     SELECT geometry, 'ocean'::text AS class FROM ne_50m_ocean
     UNION ALL
-    -- etldoc:  ne_50m_lakes ->  water_z4     
+    -- etldoc:  ne_50m_lakes ->  water_z4
     SELECT geometry, 'lake'::text AS class FROM ne_50m_lakes
 );
 
 CREATE OR REPLACE VIEW water_z5 AS (
-    -- etldoc:  ne_10m_ocean ->  water_z5    
+    -- etldoc:  ne_10m_ocean ->  water_z5
     SELECT geometry, 'ocean'::text AS class FROM ne_10m_ocean
     UNION ALL
-    -- etldoc:  ne_10m_lakes ->  water_z5    
+    -- etldoc:  ne_10m_lakes ->  water_z5
     SELECT geometry, 'lake'::text AS class FROM ne_10m_lakes
 );
 
 CREATE OR REPLACE VIEW water_z6 AS (
-    -- etldoc:  ne_10m_ocean ->  water_z6     
+    -- etldoc:  ne_10m_ocean ->  water_z6
     SELECT geometry, 'ocean'::text AS class FROM ne_10m_ocean
     UNION ALL
-   -- etldoc:  ne_10m_lakes ->  water_z6    
-    SELECT geometry, 'lake'::text AS class FROM ne_10m_lakes
+   -- etldoc:  osm_water_polygon_gen6 ->  water_z6
+    SELECT geometry, 'lake' AS class FROM osm_water_polygon_gen6
 );
 
 CREATE OR REPLACE VIEW water_z7 AS (
-    -- etldoc:  ne_10m_ocean ->  water_z7     
+    -- etldoc:  ne_10m_ocean ->  water_z7
     SELECT geometry, 'ocean'::text AS class FROM ne_10m_ocean
     UNION ALL
-    -- etldoc:  osm_water_polygon_gen3 ->  water_z7
+    -- etldoc:  osm_water_polygon_gen5 ->  water_z7
     SELECT geometry, 'lake' AS class FROM osm_water_polygon_gen5
 );
 
 CREATE OR REPLACE VIEW water_z8 AS (
-    -- etldoc:  ne_10m_ocean ->  water_z8     
+    -- etldoc:  ne_10m_ocean ->  water_z8
     SELECT geometry, 'ocean'::text AS class FROM ne_10m_ocean
     UNION ALL
-    -- etldoc:  osm_water_polygon_gen2 ->  water_z8         
+    -- etldoc:  osm_water_polygon_gen4 ->  water_z8
     SELECT geometry, 'lake' AS class FROM osm_water_polygon_gen4
 );
 
@@ -72,7 +72,7 @@ CREATE OR REPLACE VIEW water_z9 AS (
     -- etldoc:  osm_ocean_polygon_gen3 ->  water_z9
     SELECT geometry, 'ocean'::text AS class FROM osm_ocean_polygon_gen3
     UNION ALL
-    -- etldoc:  osm_water_polygon_gen1 ->  water_z9    
+    -- etldoc:  osm_water_polygon_gen3 ->  water_z9
     SELECT geometry, 'lake'::text AS class FROM osm_water_polygon_gen3
 );
 
@@ -88,7 +88,7 @@ CREATE OR REPLACE VIEW water_z11 AS (
     -- etldoc:  osm_ocean_polygon_gen1 ->  water_z11
     SELECT geometry, 'ocean'::text AS class FROM osm_ocean_polygon_gen1
     UNION ALL
-    -- etldoc:  osm_water_polygon ->  water_z11
+    -- etldoc:  osm_water_polygon_gen1 ->  water_z11
     SELECT geometry, water_class(waterway) AS class FROM osm_water_polygon_gen1 WHERE area > 40000
 );
 
@@ -96,7 +96,7 @@ CREATE OR REPLACE VIEW water_z12 AS (
     -- etldoc:  osm_ocean_polygon_gen1 ->  water_z12
     SELECT geometry, 'ocean'::text AS class FROM osm_ocean_polygon
     UNION ALL
-    -- etldoc:  osm_water_polygon ->  water_z12     
+    -- etldoc:  osm_water_polygon ->  water_z12
     SELECT geometry, water_class(waterway) AS class FROM osm_water_polygon WHERE area > 10000
 );
 
@@ -104,7 +104,7 @@ CREATE OR REPLACE VIEW water_z13 AS (
     -- etldoc:  osm_ocean_polygon ->  water_z13
     SELECT geometry, 'ocean'::text AS class FROM osm_ocean_polygon
     UNION ALL
-    -- etldoc:  osm_water_polygon ->  water_z13    
+    -- etldoc:  osm_water_polygon ->  water_z13
     SELECT geometry, water_class(waterway) AS class FROM osm_water_polygon WHERE area > 5000
 );
 
@@ -112,11 +112,11 @@ CREATE OR REPLACE VIEW water_z14 AS (
     -- etldoc:  osm_ocean_polygon ->  water_z14
     SELECT geometry, 'ocean'::text AS class FROM osm_ocean_polygon
     UNION ALL
-    -- etldoc:  osm_water_polygon ->  water_z14    
+    -- etldoc:  osm_water_polygon ->  water_z14
     SELECT geometry, water_class(waterway) AS class FROM osm_water_polygon
 );
 
--- etldoc: layer_water [shape=record fillcolor=lightpink, style="rounded,filled",  
+-- etldoc: layer_water [shape=record fillcolor=lightpink, style="rounded,filled",
 -- etldoc:     label="layer_water |<z0> z0|<z1>z1|<z2>z2|<z3>z3 |<z4> z4|<z5>z5|<z6>z6|<z7>z7| <z8> z8 |<z9> z9 |<z10> z10 |<z11> z11 |<z12> z12|<z13> z13|<z14_> z14+" ] ;
 
 CREATE OR REPLACE FUNCTION layer_water (bbox geometry, zoom_level int)
@@ -125,44 +125,44 @@ RETURNS TABLE(geometry geometry, class text) AS $$
         -- etldoc: water_z0 ->  layer_water:z0
         SELECT * FROM water_z0 WHERE zoom_level = 0
         UNION ALL
-        -- etldoc: water_z1 ->  layer_water:z1        
+        -- etldoc: water_z1 ->  layer_water:z1
         SELECT * FROM water_z1 WHERE zoom_level = 1
         UNION ALL
         -- etldoc: water_z2 ->  layer_water:z2
-        -- etldoc: water_z2 ->  layer_water:z3          
+        -- etldoc: water_z2 ->  layer_water:z3
         SELECT * FROM water_z2 WHERE zoom_level BETWEEN 2 AND 3
         UNION ALL
-        -- etldoc: water_z4 ->  layer_water:z4        
+        -- etldoc: water_z4 ->  layer_water:z4
         SELECT * FROM water_z4 WHERE zoom_level = 4
         UNION ALL
-        -- etldoc: water_z5 ->  layer_water:z5        
+        -- etldoc: water_z5 ->  layer_water:z5
         SELECT * FROM water_z5 WHERE zoom_level = 5
         UNION ALL
-        -- etldoc: water_z6 ->  layer_water:z6       
+        -- etldoc: water_z6 ->  layer_water:z6
         SELECT * FROM water_z6 WHERE zoom_level = 6
         UNION ALL
-        -- etldoc: water_z7 ->  layer_water:z7        
+        -- etldoc: water_z7 ->  layer_water:z7
         SELECT * FROM water_z7 WHERE zoom_level = 7
         UNION ALL
-        -- etldoc: water_z8 ->  layer_water:z8        
+        -- etldoc: water_z8 ->  layer_water:z8
         SELECT * FROM water_z8 WHERE zoom_level = 8
         UNION ALL
         -- etldoc: water_z9 ->  layer_water:z9
         SELECT * FROM water_z9 WHERE zoom_level = 9
         UNION ALL
-        -- etldoc: water_z10 ->  layer_water:z10                   
+        -- etldoc: water_z10 ->  layer_water:z10
         SELECT * FROM water_z10 WHERE zoom_level = 10
         UNION ALL
-        -- etldoc: water_z11 ->  layer_water:z11        
+        -- etldoc: water_z11 ->  layer_water:z11
         SELECT * FROM water_z11 WHERE zoom_level = 11
         UNION ALL
-        -- etldoc: water_z12 ->  layer_water:z2        
+        -- etldoc: water_z12 ->  layer_water:z2
         SELECT * FROM water_z12 WHERE zoom_level = 12
         UNION ALL
-        -- etldoc: water_z13 ->  layer_water:z13        
+        -- etldoc: water_z13 ->  layer_water:z13
         SELECT * FROM water_z13 WHERE zoom_level = 13
         UNION ALL
-        -- etldoc: water_z14 ->  layer_water:z14_        
+        -- etldoc: water_z14 ->  layer_water:z14_
         SELECT * FROM water_z14 WHERE zoom_level >= 14
     ) AS zoom_levels
     WHERE geometry && bbox;