[Festus2]

Bennydog: If you do a Google search, as I have just done, you will find out all sorts of information about what supplies you should have on hand in case of emergencies. For example, I found out that you should have a minimum of 2 weeks supply of drinking water. You can store this water in separate, plastic water containers or, as you are suggesting, in your water tank. Various types of water purification systems are available as well as tablets which you simply add to the water. A small amount of bleach added to your tank is something that I understand might work. Not sure of the quantity or whether or not this is something that would be ok. What about contacting your Public Health Office or similar agency about how long standing water in an RV tank is good for?

Not sure if you live in an earthquake prone zone as I do or whether your major concern is with flooding or ???? I would suggest that you do a Google search - you will find the answers to your questions and concerns - many of which come from what I would consider to be reliable and knowledgeable sources.