diff --git a/include/mondata.h b/include/mondata.h
index c3941ec65..8db4b4249 100644
--- a/include/mondata.h
+++ b/include/mondata.h
@@ -42,8 +42,8 @@
                        && (!is_clinger(ptr) || !has_ceiling(&u.uz)))
 #define is_swimmer(ptr) (((ptr)->mflags1 & M1_SWIM) != 0L)
 #define breathless(ptr) (((ptr)->mflags1 & M1_BREATHLESS) != 0L)
-#define amphibious(ptr) \
-    (((ptr)->mflags1 & (M1_AMPHIBIOUS | M1_BREATHLESS)) != 0L)
+#define amphibious(ptr) (((ptr)->mflags1 & M1_AMPHIBIOUS) != 0L)
+#define cant_drown(ptr) (is_swimmer(ptr) || amphibious(ptr) || breathless(ptr))
 #define passes_walls(ptr) (((ptr)->mflags1 & M1_WALLWALK) != 0L)
 #define amorphous(ptr) (((ptr)->mflags1 & M1_AMORPHOUS) != 0L)
 #define noncorporeal(ptr) ((ptr)->mlet == S_GHOST)
diff --git a/src/dbridge.c b/src/dbridge.c
index 91817a6bb..9855ca021 100644
--- a/src/dbridge.c
+++ b/src/dbridge.c
@@ -378,8 +378,8 @@ e_survives_at(struct entity *etmp, coordxy x, coordxy y)
     if (noncorporeal(etmp->edata))
         return TRUE;
     if (is_pool(x, y))
-        return (boolean) ((is_u(etmp) && (Wwalking || Amphibious || Swimming
-                                          || Flying || Levitation))
+        return (boolean) ((is_u(etmp) && (Wwalking || Amphibious || Breathless
+                                          || Swimming || Flying || Levitation))
                           || is_swimmer(etmp->edata)
                           || is_flyer(etmp->edata)
                           || is_floater(etmp->edata));
diff --git a/src/do_wear.c b/src/do_wear.c
index 767d80988..e22d5c8f7 100644
--- a/src/do_wear.c
+++ b/src/do_wear.c
@@ -1002,8 +1002,7 @@ Amulet_off(void)
             /* HMagical_breathing must be set off
                 before calling drown() */
             setworn((struct obj *) 0, W_AMUL);
-            if (!breathless(gy.youmonst.data) && !amphibious(gy.youmonst.data)
-                && !Swimming) {
+            if (!cant_drown(gy.youmonst.data) && !Swimming) {
                 You("suddenly inhale an unhealthy amount of %s!",
                     hliquid("water"));
                 (void) drown();
diff --git a/src/hack.c b/src/hack.c
index 7c4f290ff..b777fbd3a 100644
--- a/src/hack.c
+++ b/src/hack.c
@@ -2825,7 +2825,8 @@ pooleffects(
             if (lava_effects())
                 return TRUE;
         } else if ((!Wwalking || is_waterwall(u.ux,u.uy))
-                   && (newspot || !u.uinwater || !(Swimming || Amphibious))) {
+                   && (newspot || !u.uinwater
+                       || !(Swimming || Amphibious || Breathless))) {
             if (drown())
                 return TRUE;
         }
diff --git a/src/mhitu.c b/src/mhitu.c
index 65f947c48..94371dbfd 100644
--- a/src/mhitu.c
+++ b/src/mhitu.c
@@ -1328,8 +1328,7 @@ gulpmu(struct monst *mtmp, struct attack *mattk)
                                  : amphibious(gy.youmonst.data)
                                        ? "feel comforted."
                                        : "can barely breathe!");
-            /* NB: Amphibious includes Breathless */
-            if (Amphibious && !flaming(gy.youmonst.data))
+            if ((Amphibious || Breathless) && !flaming(gy.youmonst.data))
                 tmp = 0;
         } else {
             You("are %s!", enfolds(mtmp->data) ? "being squashed"
diff --git a/src/mon.c b/src/mon.c
index dccda6267..232abc976 100644
--- a/src/mon.c
+++ b/src/mon.c
@@ -827,8 +827,7 @@ minliquid_core(struct monst* mtmp)
          * water damage to dead monsters' inventory, but survivors need to
          * be handled here.  Swimmers are able to protect their stuff...
          */
-        if ((waterwall || !is_clinger(mtmp->data))
-            && !is_swimmer(mtmp->data) && !amphibious(mtmp->data)) {
+        if ((waterwall || !is_clinger(mtmp->data)) && !cant_drown(mtmp->data)) {
             /* like hero with teleport intrinsic or spell, teleport away
                if possible */
             if (can_teleport(mtmp->data) && !tele_restrict(mtmp)) {
diff --git a/src/steed.c b/src/steed.c
index 5f6c66bf0..4235a5e8e 100644
--- a/src/steed.c
+++ b/src/steed.c
@@ -689,7 +689,7 @@ dismount_steed(
                     if (!Underwater)
                         pline("%s falls into the %s!", Monnam(mtmp),
                               surface(u.ux, u.uy));
-                    if (!is_swimmer(mdat) && !amphibious(mdat)) {
+                    if (!cant_drown(mdat)) {
                         killed(mtmp);
                         adjalign(-1);
                     }
diff --git a/src/trap.c b/src/trap.c
index b4dbdb076..5aa53738a 100644
--- a/src/trap.c
+++ b/src/trap.c
@@ -4485,7 +4485,7 @@ drown(void)
     feel_newsym(u.ux, u.uy); /* in case Blind, map the water here */
     /* happily wading in the same contiguous pool */
     if (u.uinwater && is_pool(u.ux - u.dx, u.uy - u.dy)
-        && (Swimming || Amphibious)) {
+        && (Swimming || Amphibious || Breathless)) {
         /* water effects on objects every now and then */
         if (!rn2(5))
             inpool_ok = TRUE;
@@ -4495,7 +4495,8 @@ drown(void)
 
     if (!u.uinwater) {
         You("%s into the %s%c", is_solid ? "plunge" : "fall",
-            waterbody_name(u.ux, u.uy), (Amphibious || Swimming) ? '.' : '!');
+            waterbody_name(u.ux, u.uy),
+            (Amphibious || Swimming || Breathless) ? '.' : '!');
         if (!Swimming && !is_solid)
             You("sink like %s.", Hallucination ? "the Titanic" : "a rock");
     }
@@ -4520,8 +4521,8 @@ drown(void)
         unleash_all();
     }
 
-    if (Amphibious || Swimming) {
-        if (Amphibious) {
+    if (Amphibious || Breathless || Swimming) {
+        if (Amphibious || Breathless) {
             if (Verbose(3, drown))
                 pline("But you aren't drowning.");
             if (!Is_waterlevel(&u.uz)) {
diff --git a/src/uhitm.c b/src/uhitm.c
index b22c9acd2..e5b8c49e5 100644
--- a/src/uhitm.c
+++ b/src/uhitm.c
@@ -3094,8 +3094,7 @@ mhitm_ad_wrap(
                 }
             } else if (u.ustuck == mdef) {
                 /* Monsters don't wear amulets of magical breathing */
-                if (is_pool(u.ux, u.uy) && !is_swimmer(pd)
-                    && !amphibious(pd)) {
+                if (is_pool(u.ux, u.uy) && !cant_drown(pd)) {
                     You("drown %s...", mon_nam(mdef));
                     mhm->damage = mdef->mhp;
                 } else if (mattk->aatyp == AT_HUGS)
@@ -3124,7 +3123,8 @@ mhitm_ad_wrap(
                                  Some_Monnam(magr), coil ? "coils" : "swings");
                 }
             } else if (u.ustuck == magr) {
-                if (is_pool(magr->mx, magr->my) && !Swimming && !Amphibious) {
+                if (is_pool(magr->mx, magr->my) && !Swimming && !Amphibious
+                    && !Breathless) {
                     boolean moat = (levl[magr->mx][magr->my].typ != POOL)
                                    && !is_waterwall(magr->mx, magr->my)
                                    && !Is_medusa_level(&u.uz)
@@ -3311,7 +3311,7 @@ mhitm_ad_slim(
 
                 if (gv.vis && canseemon(mdef))
                     ncflags |= NC_SHOW_MSG;
-                if (newcham(mdef, &mons[PM_GREEN_SLIME], ncflags)) 
+                if (newcham(mdef, &mons[PM_GREEN_SLIME], ncflags))
                     pd = mdef->data;
                 mdef->mstrategy &= ~STRAT_WAITFORU;
                 mhm->hitflags = M_ATTK_HIT;
@@ -4769,7 +4769,7 @@ gulpum(struct monst *mdef, struct attack *mattk)
             case AD_PHYS:
                 if (gy.youmonst.data == &mons[PM_FOG_CLOUD]) {
                     pline("%s is laden with your moisture.", Monnam(mdef));
-                    if (amphibious(pd) && !flaming(pd)) {
+                    if ((breathless(pd) || amphibious(pd)) && !flaming(pd)) {
                         dam = 0;
                         pline("%s seems unharmed.", Monnam(mdef));
                     }
diff --git a/src/zap.c b/src/zap.c
index 16b6b4bf6..1c6b9abfd 100644
--- a/src/zap.c
+++ b/src/zap.c
@@ -50,8 +50,7 @@ static void wishcmdassist(int);
 
 #define is_hero_spell(type) ((type) >= 10 && (type) < 20)
 
-#define M_IN_WATER(ptr) \
-    ((ptr)->mlet == S_EEL || amphibious(ptr) || is_swimmer(ptr))
+#define M_IN_WATER(ptr) ((ptr)->mlet == S_EEL || cant_drown(ptr))
 
 static const char are_blinded_by_the_flash[] = "are blinded by the flash!";