From the National Heritage List for England: The monument includes a medieval conduit house, situated on a steep west facing natural hillside to the east of Canterbury. The conduit house, part of the water supply for the Abbey of St Augustine, comprises a roughly octagonal masonry collecting and settling tank, divided by an 18th century chalk block and brick wall and now entered by a later doorway on the west side. Into the tank lead four tunnelled openings and three smaller ducts which collect water from springs which issue from the aquifer. Water was delivered to the abbey by means of a three inch diameter lead pipe running out from the downslope (western) side of the structure. The tank measures a maximum of 7m (north east-south west) by 4.75m internally. The walls, which survive to a height of approximately 3m, are built of flint and chalk block on substantial chalk block foundations. Their well dressed external faces indicate that they were built free standing while the internal wall faces are of coursed flint and were originally rendered. The bed of the reservoir is of natural brickearth. The four tunnels which lead into the tank are fed by a number of subsidiary ducts and have openings approximately 1.3m high and 1m wide. Each opening is dressed with lower Greensand quoins, with larger blocks set at the point of springing for the arches. The tunnels have original fabric surviving to spring level above which each has a covering barrel vaulted roof of later flintwork. Each tunnel is blocked with brickwork some way back from its opening, beyond which lie circular dome topped brick chambers. The conduit house dates from the mid-12th century and appears to post date and lie on the south east edge of a large artificial catchment pond recorded during recent construction work. The pond has largely been destroyed and is not included within the scheduling. The reservoir of the conduit house was probably divided in the 18th century at which time a new covering of two irregular shallow barrel vaults, resting on the dividing wall, was provided. This was then covered with a thick slab of mortared brick, chalk and flint. Other repairs to the structure were carried out at this time together with the addition of two ducts and the construction of a brick filter tank. This phase of refurbishment may have been the work of Sir John Hales who, in 1733, allowed Canterbury the use of the reservoir, which he owned, to supplement its water supply. Another major phase of repair and refurbishment occurred in the 19th century when the tunnel roofs were rebuilt and the external steps and doorway were probably provided. In February 1988 the roof of the conduit house collapsed. Subsequent part excavations, carried out later that year by the Canterbury Archaeological Trust, revealed details of construction and sequence. The monument is in the care of the Secretary of State. All fence posts, scaffolding and services are excluded from the scheduling, although the ground beneath these features is included. An essential part of the infrastructure required to support a medieval monastic community was a reliable supply of water. The smallest establishments, cells for perhaps one or two, could manage with just a well, but the more populous houses required an ample and accessible source. Rivers and streams were often instrumental in deciding the precise location of monastic houses, especially in the countryside. When a religious house was planned, great care was taken to channel clean water from upstream so that it supplied the kitchen, lavatorium, infirmary and brewhouse with potable supplies. Water was also extensively used in the industrial processes carried out within many monastic precincts. If the volume of water was sufficient, its final duty was to provide a continuous flow to clean the reredorter drain. Monastic communities established in or near to towns had the same requirements for water. Local streams or rivers would be used where possible, but if these were heavily polluted the only alternative was to pipe in clean water from a spring or springs. Such arrangements, using pipes made from lead or hollowed tree trunks, were well known in the medieval period. Probably the most famous record of such a water supply is provided by the mid-12th century drawing of Prior Gilbert's piped supply for Christchurch, Canterbury. The use of gravity was esential to obtain a continuous supply of piped water. This meant tapping into sources of water located at a higher level than the recipient community and here building covered collecting and settling tanks at the spring source. From this point, clear water was piped to its destination, often through further settling tanks. Such spring head structures, usually called conduit houses, may originally have been as numerous as the monastic houses which they served, but surviving examples are now comparatively rare. Some still retain their early cover building, while others have been extensively restored in recent centuries. Due to their comparative rarity, all medieval monastic conduit houses which exhibit significant surviving archaeological remains are considered to be of national importance and worthy of protection. The conduit house for St Augustine's Abbey at Canterbury is, despite the loss of its covering structure, a well preserved example of its class. Excavations carried out in 1988 revealed the extent of the survival of the medieval structure and provided evidence of major phases of repair in the 18th and 19th centuries. These clearly demonstrated the continuing importance of the original monastic water supply both to the buildings of the abbey after the dissolution and to the town itself.