Essence of Water

Here are the results I ended up with after farming for "Essence of Water" at the following locations.
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SUMMARY:

PureSpring Elemental at Swamp of Sorrows respawn quickly and had the highest drop rate for Essence of Water;
and as a bonus the PureSpring Elementals also had a higher drop rate for Globe of Water and Elemental Water (than the alternate sites).

a. Purespring Elemental ..... at and around “(Swamp of Sorrows) 20, 56”: ..... {8.06% drop rate, 30/hour}
b. Steaming Fury ................ at and around “(Un’Goro Crater) 35, 53”: ........... {5.7% drop rate, 18/hour}
c. Ice Avatar ....................... at and around "(Winterspring) 57, 81": ................ {1.81% drop rate, 6/hour}

Note: Toxic Horror use to have the highest drop rate but as of patch 4.0.3 they have been removed from the game.
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DATA:
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10 minutes farming PureSpring Elemental at and around (Swamp of Sorrows) 20, 56;
killed 62 “Purespring Elemental” (1 hit each with lvl 84 DK) and ended up with 5 “Essence of Water” (and a few other things listed below),
for a rate of 5/10 minutes or extroplated 30/hour.

1. 5 Essence of Water (5/62 * 100 = 8.06% drop rate) (5/10 minutes = 0.5/minute. Extrapolated = 30/hour)
2. 6 Globe of Water
3. 8 Elemental Water
4. 16 Inert Elemental Piece
5. 45 Inert Elemental Shard
6. 1 Arcane Sash
7. 1 Crusader’s Pauldron’s of the Wolf
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10 minutes farming Steaming Fury at and around (Un’Goro Crater) 35, 53;
killed 52 “Steaming Fury” (1 hit each with lvl 84 DK) and ended up with 3 “Essence of Water” (and a few other things listed below),
for a rate of 3/10 minutes or extroplated 18/hour.

1. 3 Essence of Water (3/52 * 100 = 5.7% drop rate) (3/10 minutes = 0.3/minute. Extrapolated = 18/hour)
2. 3 Globe of Water
3. 4 Elemental Water
4. 18 Inert Elemental Piece
5. 24 Inert Elemental Shard
6. 1 Dark Espadon of the Whale
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10 minutes of farming Ice Avatar at and around (Winterspring) 57, 81;
killed 55 “Ice Avatar” (1 hit each with lvl 84 DK) and eneded up with only 1 “Essence of Water” (and a few other things listed below),
for a rate of 1/10 minutes or extrapolated 6/hour.

1. 1 Essence of Water (1/55 * 100 = 1.81% drop rate) (1/10 minutes = 0.1/minute. Extrapolated = 6/hour)
2. 4 Globe of Water
3. 6 Elemental Water
4. 17 Inert Elemental Piece
5. 27 Inert Elemental Shard
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It should be noted that since the Cataclysm, these can no longer be fished in the Bay of Storms in Azshara, so elementals are your only viable source to get these besides recruiting an alchemist to transmute them.

After 30 minutes farming Purespring elementals in the swamp of sorrows as a lvl 100 mage I got:
- 16 essence of water
- 22 elemental water
- 15 globe of water

Not a bad place to farm, the respawn is very quick.