I found a small bottle at Menards
Instead of bleach you can use Chlorinating Concentrate (Sodium Dichloro-s-Triazinetricone or Sodium Dichlor for short). Compare that to household bleach which has something close to 3%. One pound of Sodium Dichlor is equal to 8 gallons of bleach! Also, household bleach contains other stuff, including a lot of salt, and that salt and other stuff is what causes the bad taste and why you have to flush the fresh water tank so well.
The way I Sanitize My RV’s Fresh Water Tank.
Using something other than household bleach works well for sanitizing swimming pools and spas, the same rules apply to RV freshwater systems.
It takes only 1 teaspoon of the concentrate per 100 gallons of water to initially sanitize the system. Remember to run water through all the faucets. It’s okay to use the full teaspoon even on smaller tanks because you will be flushing the tank before adding the water you intend to drink but it seems wasteful.
Like most of us, we travel with a near-empty tank (10 gallons or so) to reduce weight. So if we arrive at the park where we plan to stay and they have well water, we drop a half teaspoon per 100 gallons of the concentrate into the fill tube and fill the water tank. This ensures the system will always be sanitized. No, you do not have to flush again. It’s the equivalent to drinking chlorinated city water. If you are filling your tank from a source that is already chlorinated then you don’t need to add the concentrate.
That said, if you don’t like to drink chlorinated water, don’t add the concentrate to the water you intend to drink. Assuming, you fill your water tank from a trusted source after you sanitized it should be safe. Or, you can add the concentrate and then filter the water you drink or cook with.
Truth is I almost always seem to be filling the freshwater tank from a chlorinated source (city water supply) so I seldom need to use the concentrate. And we do filter our drinking water.
This is not a case where more is better. This stuff is concentrated and it’s best to use just what I recommended.
Because Sodium Dichlor is so highly concentrated you only need to carry a very small container… buy the smallest container available. And it is dry crystals so there is less chance of a spill. However, because it is so concentrated it is highly corrosive so you do have to be careful how you store it and use it. You should be able to find Sodium Dichlor (Chlorinating Concentrate) at any pool supplies or spa store. There are several brands to choose from but the brand should not be a factor in your choice… it’s all the same stuff.
I have seen 2 lbs bottles for $22 on Amazon, it lasts a very long time using just a little each time.