F&M Steed first reported the leak in November 2022 to HS2 Ltd, adding security inspections carried out at the site identified the same issue.
When contacted by the BBC about the leak, it is understood Severn Trent attempted to access the building to stop the water being wasted but was unable to do so.
Roderick Steed, production director at the firm, said: “I think their attitude towards the taxpayers’ money is they’re just not bothered.
“The amount of water that’s flowed out of there in the past 32, 33 months at the taxpayers’ cost is astronomical.”
Mrs Steed said: “It’s just the annoying fact that there’s water pouring out of that building all of the time.
“The water doesn’t cause us an issue at all, unless the drains get blocked, which we then clear.
“But it’s the frustrating fact that that’s just a complete and utter waste of taxpayers’ money and of the water.
“We’ve got a heatwave this year and everybody’s talking about conserving water and there you go.”
