It is compact, barely three metres wide and just over four metres deep, roofed with a brick vault rather than the slates or corrugated iron one might expect of a rural utility building. Inside, a cast-iron water-wheel, a breastshot type in which water strikes the wheel roughly at axle height, still occupies much of the interior. The wheel measures about 2.4 metres in diameter and just over half a metre wide, and it once drove a water pump. The pump itself is no longer in use, and the wheel presumably turns no more, but both remain in place.

The building does not appear on the Ordnance Survey six-inch map of 1842, which suggests it was built sometime in the latter half of the nineteenth century. By 1905, when the revised OS map was drawn, it is marked plainly as a pump house, and that same map records something else of interest: the river to the north was impounded, its flow controlled by a weir and sluice gates. This kind of arrangement was typical of small-scale water-powered installations, where a reliable head of water had to be maintained to keep the wheel turning steadily. The tall single-arched Ketragh Bridge immediately alongside, nearly eight metres wide, gives a sense of the infrastructure that once made this a small but deliberate piece of engineering in the landscape.

The structure is built of random-rubble limestone, the same material as countless field walls and farm buildings across north Cork, which is part of why it reads so quietly in its setting. A door opening in the south wall and a window in the north would have given just enough light to work by. What it pumped, and to where, the surviving record does not say.