a gap behind it that they can run the pipes through from the mains

[Goldenboy25]

Do you know if the highlighted phrase is correct?

The only concern that he raised is the dishwasher, as he is not sure if there is a gap behind it that they can run the pipes through from the mains.

 

[elroy]

Sounds right to me.

 

[lingobingo]

Yes, it works – a gap that they can run the pipes through / a gap through which they can run the pipes.

 

[se16teddy]

Yes, I think it is grammatical, though it is a bit of a struggle to parse. The relative clause is: "they can run the pipe through [the gap] from the mains.

 

[exgerman]

If we were allowed to rewrite, I would suggest "he is not sure if there is a gap behind it to run the pipes through from the mains."