sewerage pipe through middle of property

Hi,

I'm currently looking for a PPOR and have come across a property that seems perfect EXCEPT

the sewerage plans show that the pipe runs straight through the middle of the property, diagonally from the back to the street.  The contract of sale includes a letter from the water board stating that

"Sydney Water has no record of approval being given for the erection of any
building on the above property over or adjacent to its sewer or if any required
precautions were taken.
It is Sydney Water's policy to ensure that all structures erected over or in close
proximity to a sewer have footings, which will not transmit any load of the
structures to the conduit and allow access 'for maintenance purposes without
affecting the stability of the structure.
In the circumstances, Sydney water will not object to the structure remaining in its
present state but will not accept any responsibility for claims of damage arising out
of the presence on the property of the sewer and maintenance operations carried
out thereon, and which do not result from negligence on the part of Sydney Water."

My husband has talked to the waterboard who said that the likelihood of them needing to tear up the house floors is low because the pipes are cast iron and very sturdy.  They fix everything they need to internally.  He said its highly likely the approvals were lost as waterboard records were poor prior to 40 years ago – which is about the age of the house.

Has anyone had experience with this.  Is this one of those problems that has a solution or is it a bad buy because its not fixable.

What we would like to ultimately do is one day renovate or rebuild but unsure of the implications of this sewerage pipe.

Thanks for your thoughts

Sue