Should we fear death by water? James Joyce wrote in Ulysses "A seachange this, brown eyes, saltblue. Seadeath, mildest of all deaths known to man."
Although on line 55 Madame Sosostris consels "Fear death by water." the death of Phlebas, the drowned Phoenician Sailor, in Part IV is described as a gentle, peaceful death. Also non-fearful, we see the drowned sailor sea-changed into something rich and strange ("Those are pearls that were his eyes" appears both on line 48 and line 125. The line comes from Ariel's song in The Tempest.)
On line 172 we have an allusion to Ophelia in Hamlet, who sang songs as she drowned.
In the deleted part of Part IV there is a shipwreck with more deaths but these also are peaceful deaths and one sailor cracks a joke just before the wreck (see the draft.)
On the other hand, in The Waste Land there does however appear two small scenes that invoke a fearful watery death.
There is also a mention of the Mylae sea battle on line 70 and King Ludwig's drowning mentioned in the Miscellanea page for line 8.
In Shakepeare's Richard III, Clarence describes a dream of a terrible drowning death. Despite the fearful scene at the sea-bed we can see another description of Shakespeare's wonderful line "Those are pearls that were his eyes."
Ada Eliot, the sister of T.S. Eliot's father, drowned in a skating accident at sixteen ( Letters page 12.)
You can put the cross reference list for death by water here.