What could have caused this

[Loinsway]

I recently looked under the floor and found this? What could have caused this?

Could it have been there since installation? I can see general construction debris and dirt. Not the best way to leave a site, but I can't see evidence of infestation, unless the dark spots are mouse droppings?

i initially thought it could be a rat infestation but then there are no droppings and the circles seem neatly cut.. it just looks awfully messy and thought it could be a rat looking at the back wall.. does this look chewed or hacked?

The white pipe is the kitchen sink pipe and the blue one is for the dishwasher. Why are they not connected and should the blue pipe just go into the floor?

I'd clean it out and then put down some kitchen roll, that way you can see if there's a leak at least

A friend had something which sounds similar in her home - the dishwasher drain ran through the floor to the solum beneath- no connection to the house drains. It stank, which is why she looked.

You may need to cut a hole in the floor and see what’s underneath. Some people take appalling shortcuts.

Bumping for you. The blue pipe is probably the supply of clean water to your dishwasher, whereas the white is for dirty waste water to drain out from sink (and dishwasher drain pipe likely connects to this higher up). What is causing your concern? Is there a leak? A bad smell from the drains? Or are you simply shocked by how untidy it is?

Yes you’re right. The blue pipe is the fresh water coming in. it just looks very messy like it has been chewed. The white pipe from the sink looks like it has been hacked off and isn’t going into the grey waste pipe correctly.

I can't see clearly, but think the white pipe has a bend, so the waste water exits further down the pipe than we can see. I think the "chewed" wood is a type of particle board that is firm but easy to snap off to suit, a bit like a weetabix... 😁.