Water based means we use water to carry the protective ingredients in the sealers. This means that anywhere water can penetrate into the wood, so does our sealer. Using water also means we are not using harmful chemicals. Our Cedar Seal and Deck Seal are completely safe for the environment. Also, Cedar Seal and Deck Seal are much more concentrated than others on the market, therefore you will get a much longer lasting finish for your money. Basically our water based sealers are easier to use, they are safer to use and keep your wooden decks and cedar roofs and fences looking cleaner and newer for years.