There are water based sealents out there, but the natural tendency of water being repelled by organics (naptha, kerosene, diesel, etc. etc.) is mostly their claim to fame. Yes, you do have to apply it at least once a year because the organics will flash off over time. If you look at the MSDS, there are not a lot of solids in the mixture, so not a lot of stuff to coat the substrate. But, if you can re-apply every year, that stuff really works.