[sbw1]

Go easy on the bleach as it will damage your seals in the head if you use too much. The key to keeping the water tank fresh is to use it on a regular bases even if that means running it dry once a week and refilling it with fresh water from a good source of water from a chlorinated public water utility. Well water is suspect if it comes from a private well.

There are water treatment chemicals available from marine stores that work very effectively. We have used Aquafresh for years because our local store sells that brand. It is powdered bleach and has good instructions. These tell you how to cure the bad smell you are experiencing. Once you have gotten on top of the problem, follow the directions on the package to keep things fresh.

We put our boat away with the water tank drained. In the spring, we follow the procedure on the package which essentially tells you to double dose for the tank, fill the fresh water lines with water, (i.e.. the fresh water faucets, the head line, the ice maker, transom shower, etc.) and let things sit for 23 to 48 hours. Then you flush the tank by running it dry and refilling with fresh water. We make 20 to 40 pounds of ice with the highly chlorinated water and throw that overboard. We run the tank dry twice with fresh water from our local water system and make another 40 pounds of ice with that water and throw that overboard. Once this cycle is completed we drink the water and use the ice. We do not continue to use chemicals.  If we do not empty the tank in a week, we run the taps until the tank is empty and refill it. When we are on the boat, our tank is refreshed daily because of showers and normal daily usage. Properly maintained, tank water is very safe to use provided you fill the tank with a good source of water.