AmsOil Makes One...
You can buy a water separator from AmsOil at their website, but unless you drive cross-country regularly, encountering varying fuel qualities, and degrees of humidity, they really don't make much sense. And, you probably don't need one. Driving in the same relative area, and using a quality diesel fuel while keeping your tank refilled regularly is what really matters in these terms...
"We drive into the future using only our rearview mirror."
- Marshall McLuhan -
Northern California Wine Country...
"Turbos whistle, grapes wine..."