Gee, i have been driving diesels since I bought my 1981 VW Jetta Coupe 2 door diesel, all over the West, to the Rockies and back, logged 1.3 million miles. Almost always fill up with Automobile diesel fuel, a good brand, and I've never had a bad tank of fuel, or found water in my fuel filter. Truck stops and high turnover are a myth. What isn't a myth is a station that services the filters regularly, and picks up diesel fuel off the surface of the tank, not the bottom, where the water is, since water is more dense and heavier than diesel fuel.
It's a non issue.... keep the diesel turnover in your truck diesel tank high, run a little bit of Power Service white bottle to keep your fuel dry every 3 or 4 tanks, and you should have no problem with it out west here. I can't speak for midwest, tornado, or Hurircane and flood water type country where it's very easy to get water into the storage tanks where you buy your fuel. I suggest topping off BEFORE the bad wet flooding weather hits, and risks contaminating all the fuel stations fuel with water.
West of the Rockies, we just don't see much water in diesel fuel, except perhaps maybe in the North West states, WA and OR.
As for DPF's, I own a Passat and 2 Touaregs with DPFs. I've frequented many a Bulletin Board, and it's generally, n most cases, city folks that buy diesels and drive them short distances, not far enough for a full warm up and enough distance for a full burn off of the DPF.
They will either find a bad sensor for temperature readings, if that's what your dash says, or they will have to perform a manual burn off of your DPF. VW has to do the same thing, rarely, when Grannies buy TDI's and use them to run 3 or 4 miles to get groceries or to go play Bingo at the senior center.
Buy a Scan Gauge, and program it and know when you are coming up on a DPF burn off, so you can help it along with a little bit longer drive.
http://www.scangauge.com/support/user-manuals/scangaugeii-user-manuals/
Someone might want to try this coding and see if on one of these trucks, this X gauge programming works to determine and give a read out of SOOT LOAD on the DPF... Get back to us if you try it.
http://forums.tdiclub.com/showpost.php?p=4801460&postcount=8