Filter House at Pontsticill Water Treatment Works

The original L- shaped range consists of 2 wings joined by a corner tower. Built of brick rendered in roughcast with a Welsh slate roof, copper dome to the tower. The main wings have 10 pane metal-framed windows under the dentilled eaves and a large semicircular window with decorative voussoir-type mouldings in the gable ends (now appears internally in extended range). The tower which holds a staircase is 4 storeys with similar larger metal-framed windows, smaller upper storey windows with some billet moulding, and is topped by a green copper dome. The extended range to E is slightly smaller with a smaller tower lacking the dome.

Roof is supported by a network of bolted steel trusses and lined with painted timber. Beds are of concrete, each with valve; railed walkway has terrazzo floor. At lower level is the filter machinery for each bed, the box tanks lined with white and brown tiles. Former outer wall with large round headed steel-framed multi-pane windows now an internal wall to new development. By the staircase is a tiled water sampling point.