Manx Utilities admits there are issues with surcharge leaking into gardens at properties in Onchan after heavy rain but says it would be too expensive to deal with the whole network.

The authority admits it is aware there are a number of properties in Ashely Park with manholes in the garden which is an unwanted quirk ‘inherited’ by it.

Onchan MKH says residents have complained of sewage leaking into their properties due to the issue although Manx Utilities says it is ‘not aware’ of wastewater issues.

Manx Utilities chairman John Wannenburgh responded to a written Tynwald question from Mr Callister who asked: ‘When the Manx Utilities Authority will address the issue of raw sewage leaking into properties at Ashley Park, Onchan during periods of heavy rain; and if he will make a statement.’

Mr Wannenburgh said: ‘Manx Utilities is not aware of the issue of wastewater leaking into properties in Ashley Park. Manx Utilities is however fully aware of manholes situated in a number of rear gardens in the Ashley Park area which surcharge during intense rainfall events.

‘The flooding of the gardens in various locations in Onchan is a legacy issue inherited by Manx Utilities’ predecessors when the sewer networks were brought back into central government from local authorities.

‘The expansion of Onchan without upsizing the sewer network has left a number of areas with sewers at or over capacity during heavy rain.’

But Mr Wannenburgh says a major project to upgrade the system would be impractical and explained other ways the authority is addressing the issue.

He said: ‘The wholesale upsizing of the network to address these issues would be hugely disruptive and prohibitively expensive, hence our progressing with multiple smaller scale schemes in order to reduce flows within the network.

‘Sewer rehabilitation works have been undertaken in the upstream catchment to remove groundwater from the network, with dye tracing also identifying surface water flows from properties incorrectly connected into foul sewers.

‘Continued investigations over the forthcoming winter hope to further identify surface water flows that can be removed, while developing suitable schemes to divert these flows away from the properties that are affected.

‘Manx Utilities will continue to work alongside the Department of Infrastructure to remove any highway drainage from combined sewers in the area, where appropriate.’

Those affected by any flooding should contact Manx Utilities’ operational team on 687687 at the time of an event.