diff --git a/mods/default/init.lua b/mods/default/init.lua
index 430f761..a0fe925 100644
--- a/mods/default/init.lua
+++ b/mods/default/init.lua
@@ -466,6 +466,7 @@ minetest.register_node("default:water_flowing", {
 	diggable = false,
 	drowning = 1,
 	buildable_to = true,
+	is_ground_content = false,
 	liquidtype = "flowing",
 	liquid_alternative_flowing = "default:water_flowing",
 	liquid_alternative_source = "default:water_source",
@@ -492,6 +493,7 @@ minetest.register_node("default:water_source", {
 	diggable = false,
 	drowning = 1,
 	buildable_to = true,
+	is_ground_content = false,
 	liquidtype = "source",
 	liquid_alternative_flowing = "default:water_flowing",
 	liquid_alternative_source = "default:water_source",
@@ -524,6 +526,7 @@ minetest.register_node("default:lava_flowing", {
 	diggable = false,
 	drowning = 1,
 	buildable_to = true,
+	is_ground_content = false,
 	liquidtype = "flowing",
 	liquid_alternative_flowing = "default:lava_flowing",
 	liquid_alternative_source = "default:lava_source",
@@ -551,6 +554,7 @@ minetest.register_node("default:lava_source", {
 	diggable = false,
 	drowning = 1,
 	buildable_to = true,
+	is_ground_content = false,
 	liquidtype = "source",
 	liquid_alternative_flowing = "default:lava_flowing",
 	liquid_alternative_source = "default:lava_source",