The pumping station consists of two parts: a superstructure comprising a rectangular two-storey loadbearing brick building; and a substructure constructed of concrete which houses machinery and sewage chambers. Architecturally, the building was designed in a restrained version of the
Federation Free Style, exploiting the contrasts of surface and colour inherent in good
brickwork and
sandstone. Classical elements are evident in the symmetrical
facade, the round-arched door openings and the echoes of balustrading in the
parapets. Externally there are two principal elevations. The front of the building addresses William Henry Street and is a symmetrical composition of face brick with sandstone dressings in three
bays, the centre one treated as a breakfront accommodating as entrance
porch. There are projecting sandstone string courses at first floor level, window sill level and
transom level. The parapet has a row of vertical recessed panels on each side of a raised and panelled centre section, giving the breakfront the character of a triumphal arch. The entry bay has a round arch with bullnosed intrados and moulded stone
imposts at window transom level. The entrance consists of a pair of original four panel timber doors with
fanlight. The Pyrmont Street facade is divided up into three bays, all treated differently to reflect functions within the building. The south bay continues the front facade treatment and is dominated by the entrance lobby which is expressed by a bold frontispiece of rock faced
ashlar sandstone above a sandstone
plinth. The frontispiece is penetrated by a Florentine-arched doorway having rock faced
voussoirs and a smooth-tooled intrados. The centre bay expresses the former controlling room above and a store room below. The north bay is dominated by a ground floor arch, which is of brick and matches the arch over the William Henry Street entrance. Internally, the ground floor comprises a lobby accessed from Pyrmont Street and containing
stairs which provide access the offices above and machinery chamber below. The remainder of this floor consists of storage and loading bay. The first floor comprised three spaces. On the south there was an office, in the middle was a controlling room and to the north there were a lavatory and store room. To the north there is vacant land (formerly the A.M.L.&F.; Wool Warehouse); to the west is another vacant block of land (formerly another woolstore); and to the south is the modern William Henry Bridge (which is higher and greatly enlarged by comparison with the former overbridge that was there when SP001 was erected - in 1900 the footpath of William Henry Street was about level with the upper floor of the Station. Across the road is the
Powerhouse Museum (formerly the
Ultimo Tramway Power House). The exterior of the building is substantially intact. Much of the original plant and equipment has been replaced.
Modifications and dates The pumping station is substantially intact. Two pair of
wrought iron gates have been removed from the arched entrances. Its function as the controlling station for the other 17 stations ceased and the switchboards have been removed from the first floor office. The single storey garage wing attached to the south elevation is an intrusive addition. Most of the mechanical and electrical components were upgraded during the 1970s. Direct current was replaced by alternating current in , and it was supplied by the City Council of Sydney Electricity Department which was the forerunner of the
Sydney County Council. == Heritage listing ==