Isoflavones are found in small amounts in a number of legumes, grains, and vegetables, but soybeans are by far the most concentrated source of isoflavones in the human diet (104, 105) .
Standing water under a house is usually the result of only two things; either a leaking water line, or from surface water drainage around the house. If it was from a leaking water line, the leak would have to be substantial, and you would hear running water in the house.
If you can put a couple of cups of water in the toilet, and it stays there, and is not full at this point, then that is unlikely to be your cause of the water pump running. There are low water drains in most RV's and one might be open, yet this will be a fairly fast leak to under the RV.