The Old Man and Old Woman's house is surrounded by stagnant water. We detect symbolism. The fact that the water is stagnant could represent the way in which the elderly couple's lives have stalled. For years all they've really done is play make-believe and tell the same old stories. Their lives have become just as stagnant as the water surrounding their house. The fact that the house is basically an island could also be symbolic of their isolation. Though the two have been together for many years, they still feel totally alone. The water could be symbolic of the distance between them and between all human beings.
Water could also be seen to represent time in the play. There are hints throughout that time is in some ways cyclical. The old couple seems doomed to repeat the same actions over and over until their death. At one point, the couple is recounting how the Old Man has repeatedly failed in life. The Old Woman comments, "All that's gone down the drain, alas...down the old black drain" (56). With this image, we imagine water spiraling down into the darkness of the drain. It calls to mind how the Old Man's life has been one big repetitive loop, which is dragging him inevitably towards the darkness of death.