diff --git a/common/bspfile.cc b/common/bspfile.cc
index fcb3beb2..bb1363e8 100644
--- a/common/bspfile.cc
+++ b/common/bspfile.cc
@@ -148,7 +148,7 @@ struct gamedef_q1_like_t : public gamedef_t
         } else if (contents.extended & CFLAGS_DETAIL_FENCE) {
             return 4;
         } else if (contents.extended & CFLAGS_DETAIL_ILLUSIONARY) {
-            return 3;
+            return 2;
         } else if (contents.extended & CFLAGS_ILLUSIONARY_VISBLOCKER) {
             return 2;
         } else {
@@ -157,9 +157,9 @@ struct gamedef_q1_like_t : public gamedef_t
 
                 case CONTENTS_SKY: return 6;
 
-                case CONTENTS_WATER: return 2;
-                case CONTENTS_SLIME: return 2;
-                case CONTENTS_LAVA: return 2;
+                case CONTENTS_WATER: return 3;
+                case CONTENTS_SLIME: return 3;
+                case CONTENTS_LAVA: return 3;
 
                 case CONTENTS_EMPTY: return 1;
                 case 0: return 0;
diff --git a/common/bsputils.cc b/common/bsputils.cc
index 5832fc01..2da2fad4 100644
--- a/common/bsputils.cc
+++ b/common/bsputils.cc
@@ -417,6 +417,28 @@ const bsp2_dnode_t* BSP_FindNodeAtPoint(
     return BSP_FindNodeAtPoint_r(bsp, model->headnode[0], point, wanted_normal);
 }
 
+static const mleaf_t *BSP_FindLeafAtPoint_r(
+    const mbsp_t *bsp, const int nodenum, const qvec3d &point)
+{
+    if (nodenum < 0) {
+        return BSP_GetLeafFromNodeNum(bsp, nodenum);
+    }
+
+    const bsp2_dnode_t *node = &bsp->dnodes[nodenum];
+    const vec_t dist = bsp->dplanes[node->planenum].distance_to_fast(point);
+
+    if (dist >= 0) {
+        return BSP_FindLeafAtPoint_r(bsp, node->children[0], point);
+    } else {
+        return BSP_FindLeafAtPoint_r(bsp, node->children[1], point);
+    }
+}
+
+const mleaf_t* BSP_FindLeafAtPoint(const mbsp_t* bsp, const dmodelh2_t* model, const qvec3d& point)
+{
+    return BSP_FindLeafAtPoint_r(bsp, model->headnode[0], point);
+}
+
 // glm stuff
 std::vector<qvec3f> GLM_FacePoints(const mbsp_t *bsp, const mface_t *face)
 {
diff --git a/include/common/bsputils.hh b/include/common/bsputils.hh
index 46c8eae6..f78f6f16 100644
--- a/include/common/bsputils.hh
+++ b/include/common/bsputils.hh
@@ -66,6 +66,8 @@ const mface_t *BSP_FindFaceAtPoint(
 const bsp2_dnode_t *BSP_FindNodeAtPoint(
     const mbsp_t *bsp, const dmodelh2_t *model, const qvec3d &point, const qvec3d &wanted_normal);
 
+const mleaf_t *BSP_FindLeafAtPoint(const mbsp_t *bsp, const dmodelh2_t *model, const qvec3d &point);
+
 const qvec3f &Face_PointAtIndex(const mbsp_t *bsp, const mface_t *f);
 const qvec3f &Vertex_GetPos(const mbsp_t *bsp, int num);
 qvec3d Face_Normal(const mbsp_t *bsp, const mface_t *f);
diff --git a/qbsp/test_qbsp.cc b/qbsp/test_qbsp.cc
index 070ca5d3..8b0fb958 100644
--- a/qbsp/test_qbsp.cc
+++ b/qbsp/test_qbsp.cc
@@ -374,6 +374,18 @@ TEST(testmaps_q1, simple_worldspawn_detail)
     ASSERT_EQ(bsp.dfaces.size(), 14);
 }
 
+TEST(testmaps_q1, water_detail_illusionary)
+{
+    const mbsp_t bsp = LoadTestmap("qbsp_water_detail_illusionary.map");
+
+    ASSERT_FALSE(map.leakfile);
+
+    const qvec3d inside_water_and_fence{-20, -52, 124};
+    const auto *leaf = BSP_FindLeafAtPoint(&bsp, &bsp.dmodels[0], inside_water_and_fence);
+    ASSERT_EQ(leaf->contents, CONTENTS_WATER);
+}
+
+
 TEST(testmaps_q1, noclipfaces)
 {
     const mbsp_t bsp = LoadTestmap("qbsp_noclipfaces.map");
diff --git a/testmaps/qbsp_water_detail_illusionary.map b/testmaps/qbsp_water_detail_illusionary.map
new file mode 100644
index 00000000..a2ef7385
--- /dev/null
+++ b/testmaps/qbsp_water_detail_illusionary.map
@@ -0,0 +1,91 @@
+// Game: Quake
+// Format: Valve
+// entity 0
+{
+"mapversion" "220"
+"classname" "worldspawn"
+"wad" "deprecated/free_wad.wad;deprecated/fence.wad;deprecated/origin.wad;deprecated/hintskip.wad"
+"_wateralpha" "0.5"
+"_tb_def" "builtin:Quake.fgd"
+// brush 0
+{
+( -112 -112 96 ) ( -112 -111 96 ) ( -112 -112 97 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 0 ] 0 2 2
+( -80 -96 80 ) ( -81 -96 80 ) ( -80 -96 81 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -80 -432 80 ) ( -80 -431 80 ) ( -81 -432 80 ) orangestuff8 [ 1 0 0 -16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 -112 96 ) ( -161 -112 96 ) ( -160 -111 96 ) orangestuff8 [ -1 0 0 16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 0 96 ) ( -160 0 97 ) ( -161 0 96 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( 64 -432 80 ) ( 64 -432 81 ) ( 64 -431 80 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 0 ] 0 2 2
+}
+// brush 1
+{
+( -112 -96 96 ) ( -112 -95 96 ) ( -112 -96 97 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 0 ] 0 2 2
+( -80 0 80 ) ( -81 0 80 ) ( -80 0 81 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -80 -416 80 ) ( -80 -415 80 ) ( -81 -416 80 ) orangestuff8 [ 1 0 0 -16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 -96 224 ) ( -161 -96 224 ) ( -160 -95 224 ) orangestuff8 [ -1 0 0 16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 16 96 ) ( -160 16 97 ) ( -161 16 96 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( 64 -416 80 ) ( 64 -416 81 ) ( 64 -415 80 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 0 ] 0 2 2
+}
+// brush 2
+{
+( -112 -208 96 ) ( -112 -207 96 ) ( -112 -208 97 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 0 ] 0 2 2
+( -80 -112 80 ) ( -81 -112 80 ) ( -80 -112 81 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -80 -528 80 ) ( -80 -527 80 ) ( -81 -528 80 ) orangestuff8 [ 1 0 0 -16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 -208 224 ) ( -161 -208 224 ) ( -160 -207 224 ) orangestuff8 [ -1 0 0 16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 -96 96 ) ( -160 -96 97 ) ( -161 -96 96 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( 64 -528 80 ) ( 64 -528 81 ) ( 64 -527 80 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 0 ] 0 2 2
+}
+// brush 3
+{
+( -128 -112 96 ) ( -128 -111 96 ) ( -128 -112 97 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 0 ] 0 2 2
+( -256 -96 80 ) ( -257 -96 80 ) ( -256 -96 81 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -256 -432 80 ) ( -256 -431 80 ) ( -257 -432 80 ) orangestuff8 [ 1 0 0 -16 ] [ 0 -1 0 16 ] 180 2 2
+( -336 -112 224 ) ( -337 -112 224 ) ( -336 -111 224 ) orangestuff8 [ -1 0 0 16 ] [ 0 -1 0 16 ] 180 2 2
+( -336 0 96 ) ( -336 0 97 ) ( -337 0 96 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( -112 -432 80 ) ( -112 -432 81 ) ( -112 -431 80 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 0 ] 0 2 2
+}
+// brush 4
+{
+( 64 -112 96 ) ( 64 -111 96 ) ( 64 -112 97 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 0 ] 0 2 2
+( -64 -96 80 ) ( -65 -96 80 ) ( -64 -96 81 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -64 -432 80 ) ( -64 -431 80 ) ( -65 -432 80 ) orangestuff8 [ 1 0 0 -16 ] [ 0 -1 0 16 ] 180 2 2
+( -144 -112 224 ) ( -145 -112 224 ) ( -144 -111 224 ) orangestuff8 [ -1 0 0 16 ] [ 0 -1 0 16 ] 180 2 2
+( -144 0 96 ) ( -144 0 97 ) ( -145 0 96 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( 80 -432 80 ) ( 80 -432 81 ) ( 80 -431 80 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 0 ] 0 2 2
+}
+// brush 5
+{
+( -112 -112 240 ) ( -112 -111 240 ) ( -112 -112 241 ) orangestuff8 [ 0 1 0 -16 ] [ 0 0 -1 0 ] 0 2 2
+( -80 -96 224 ) ( -81 -96 224 ) ( -80 -96 225 ) orangestuff8 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -80 -432 224 ) ( -80 -431 224 ) ( -81 -432 224 ) orangestuff8 [ 1 0 0 -16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 -112 240 ) ( -161 -112 240 ) ( -160 -111 240 ) orangestuff8 [ -1 0 0 16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 0 240 ) ( -160 0 241 ) ( -161 0 240 ) orangestuff8 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( 64 -432 224 ) ( 64 -432 225 ) ( 64 -431 224 ) orangestuff8 [ 0 -1 0 16 ] [ 0 0 -1 0 ] 0 2 2
+}
+// brush 6
+{
+( -112 -112 108 ) ( -112 -111 108 ) ( -112 -112 109 ) *swater5 [ 0 1 0 -16 ] [ 0 0 -1 0 ] 0 2 2
+( -80 -96 92 ) ( -81 -96 92 ) ( -80 -96 93 ) *swater5 [ -1 0 0 16 ] [ 0 0 -1 0 ] 180 2 2
+( -80 -432 92 ) ( -80 -431 92 ) ( -81 -432 92 ) *swater5 [ 1 0 0 -16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 -112 148 ) ( -161 -112 148 ) ( -160 -111 148 ) *swater5 [ -1 0 0 16 ] [ 0 -1 0 16 ] 180 2 2
+( -160 0 108 ) ( -160 0 109 ) ( -161 0 108 ) *swater5 [ 1 0 0 -16 ] [ 0 0 -1 0 ] 180 2 2
+( 64 -432 92 ) ( 64 -432 93 ) ( 64 -431 92 ) *swater5 [ 0 -1 0 16 ] [ 0 0 -1 0 ] 0 2 2
+}
+}
+// entity 1
+{
+"classname" "info_player_start"
+"origin" "-88 -64 120"
+}
+// entity 2
+{
+"classname" "func_detail_illusionary"
+// brush 0
+{
+( -40 -76 96 ) ( -40 -75 96 ) ( -40 -76 97 ) {trigger [ 0 -1 0 -16 ] [ 0 0 -1 0 ] 0 1 1
+( -8 -72 96 ) ( -8 -72 97 ) ( -7 -72 96 ) {trigger [ 1 0 0 16 ] [ 0 0 -1 0 ] 0 1 1
+( -8 -76 96 ) ( -7 -76 96 ) ( -8 -75 96 ) {trigger [ -1 0 0 -16 ] [ 0 -1 0 -16 ] 0 1 1
+( 56 -28 224 ) ( 56 -27 224 ) ( 57 -28 224 ) {trigger [ 1 0 0 16 ] [ 0 -1 0 -16 ] 0 1 1
+( 56 -36 112 ) ( 57 -36 112 ) ( 56 -36 113 ) {trigger [ -1 0 0 -16 ] [ 0 0 -1 0 ] 0 1 1
+( 24 -28 112 ) ( 24 -28 113 ) ( 24 -27 112 ) {trigger [ 0 1 0 16 ] [ 0 0 -1 0 ] 0 1 1
+}
+}