Sewage data not accurate, water boss tells MPs
UK ParliamentA water firm boss has told MPs information released about a sewage overflow was "not necessarily accurate" because it was not measured.
Northumbrian Water's Heidi Mottram was quizzed about data, first reported by the BBC, which estimated a pumping station in Whitburn, South Tyneside, had released one million tonnes of raw sewage into the North Sea in 2023.
Ms Mottram said the estimate was "probably not unreasonable" but it was "inferred as opposed to being measured".
The Environment Agency (EA) has been approached for comment.
The one million tonne figure was provided by Northumbrian Water in June 2024 following several unsuccessful Freedom of Information (FOI) requests from resident Steve Lavelle.
It was only released after a first-tier tribunal ruled earlier that year the firm had to provide such figures.
Ms Mottram, who was speaking at an Environment, Food and Rural Affairs Committee inquiry into reforming the water sector, said an estimate was given because the resident had asked for information "we wouldn't routinely collect either for our operations or for a regulator".
In response, Liberal Democrat Alistair Carmichael MP, the committee's chair, asked: "When you say inferred, is that another way of saying you don't actually know?"
Ms Mottram replied: "We manage the system in a different way using different information than specifically how that customer wanted."
She said she believed the true figure was "not as high" as a million tonnes but did not want to "guess" what it actually was.
She said she would provide the committee with the "exact number".
'Depends on rainfall'
Ms Mottram said the firm was "regulated" on how often an overflow spilled and for how long.
The data Mr Lavelle had requested was specifically about how much sewage had actually been pumped into the North Sea.
"You could calculate what might be happening but it's not necessarily accurate," she told the hearing earlier.
The UK has combined sewage systems which mean rain and sewage share the same pipes. If there is too much rain, sewage treatment works can be overwhelmed. Sewage is spilled into waterways to prevent the system backing up.
"[It's] about trying to decide how much water might have gone out," she said. "Because of course, sometimes it will be low or high depending on what the rainfall is."
The inquiry, which continues on Wednesday, has seen several water bosses quizzed on their companies' financial and environmental performance.