Permitted development
A. Development by a water authority for the purposes of their functions consisting of—
(a)development not above ground level required in connection with the provision, improvement, maintenance or repair of a sewer, outfall pipe, sludge main or associated apparatus,
(b)development not above ground level required in connection with the supply of water or for conserving, redistributing or augmenting water resources, or for the conveyance of water treatment sludge,
(c)development in, on or under any watercourse or land drainage works and required in connection with the improvement or maintenance or repair of that watercourse or those land drainage works,
(d)the provision of a building, plant or machinery or apparatus in, on, over or under land for the purpose of survey or investigation,
(e)the maintenance, improvement or repair of works for measuring the flow in any watercourse or channel,
(f)the installation in a water distribution system of a booster station, valve house, meter or switch-gear house,
(g)any works authorised by or required in connection with an order made under section 1 or 2 of the Drought Act 1976(),
(h)any other development in, on, over or under their operational land, other than the provision of a building but including the extension or alteration of a building.