Some additional tidbits...
- Water does not weigh about 9# per gallon. Fresh water weighs more in the range of 8.3 > 8.35 PPG.
- Water settles through Avgas at a rate of Apprx. 15 Min. per vertical foot. It takes much longer with Kerosene/Jet A, Etc.
- If sumping a Kerosene burner, and are having trouble telling water from fuel; you can pour some fuel on a piece of paper. When the paper dries the fuel will leave a noticable stain.
- The primary reason for shaking the wings is to dislodge water that may be puddled in various parts of the tank floor so as to have it flow to a low point drain. This is sometimes an issue with bladder tanks and can be an issue with an aircraft parked at a severe enough angle.
- I too have had a couple incidents incidents of large amounts of water in the fuel as well, bad fuel caps. I also have had water find its way into the static system. Be sure to check the static system drains for water as well...