Eddie do you know if the carpet was treated with a protector? It could be faulty application of protector at the carpet retailer's warehouse - a lot of them pre-cut the carpet off the roll into the approximate room sizes, lay them out on the floor and treat them the night before. Then they roll them up, take them to the job and fit. There could have been something happen at this stage.
Sometimes where the hose joins the pressure sprayer it starts to leak doesn't it, I think we've all picked our sprayer up at some point and found it sitting in a puddle!
One retailer I do protection for has a leaky warehouse roof - if it's forecast rain they have to chalk-mark the floor and not put any carpet under where the drips are going to land!!