Southern Water confirmed the incident occurredÂ in the early hours of this morning after the error struck at its treatment works at Budds Farm in Havant.Â
The accident meant '˜highly diluted' wastewater poured from the firm's storm tanks into Langstone Harbour for a period of 21Â minutes.Â
A spokesperson confirmed the volume of the discharge was an '˜absolute maximum' of 378 cubic metres '“Â the equivalent of 378,000 litres.Â
Hayling Island campaigner Mark Coates dubbed the discharge '˜disgusting' but '˜unsurprising'.Â
'˜This is a prime example of the vast quantities of sewage from Southern Water which pollute our waters,' said Mr Coates.Â
'˜And looking through recent discharge notifications, it is not surprising at all.'Â
According to Southern Water, the discharge is now being investigatedÂ by its pollutions team.Â
In a statement, the firm added: '˜Although emergency generators did kick in, the original fault in high voltage gear may have damaged the power line and only parts of the site received back up power.
'˜Our teams worked through the night and with the assistance of UK Power Networks and Schneider Electrical we now have four generators running and the site is now running with a very low risk of further releases.'Â
As an act of transparency, Mr Coates has urged to firm toÂ publicise the specific volume of wastewater discharge '“Â caused by faults or rainwater, as is standard '“Â on the Langstone Harbour Board (LHB) website from now on.Â
The website currently publishes frequently-updatedÂ alerts of wastewater discharge into the harbour, but the notifications do not say how much sewage has been released.Â
For example when it rained on August 27, a notification published on the LHB website indicatesÂ 580 minutes' worth of discharge made its way into Langstone Harbour over 28 releases '“Â as pressure built upÂ on the Southern Water Network.Â
'˜The quantity releasedÂ should by law, or certainly as a courtesy from Southern Water, be part of release notifications,' said Mr Coates.Â
'˜The figures from August 27 look bad '“Â and they could even be worse than this fault '“Â but they are relatively meaningless.'Â
Southern Water said it takes its environmental responsibilities '˜very seriously' and said its team has '˜taken every measure to minimise the impact of this issue'.