Three things to do when storing water for a long period of time.
1. Build a large water storage system with water filtration.
When living off grid, water is critical to the survival of your family, plants and livestock. Be sure to build a large enough water storage system to supply your family with 3 Gallons of water per person per day for the length of the dry season. Here is the equation.
Water Storage Tank Size =((Family Member Number x 3) x Days of the average dry Season)
Were my family of 5 lives in Northern California it would be at least a 2500 Gallon Water Tank. I would prefer to double this so that we have ample water for chickens and gardening.
2. Be sure to keep water tanks and cisterns in the shade and covered at all times.
It is very easy to keep your water storage cisterns or tanks covered with shade cloth. Just put 4 steel poles in the ground and attach a 90% Black Shade Cloth to the top of the poles.
3. Invest in Cone Bottom tanks for easy clean-out.
Cone bottom tanks cost more than standard round water tanks but they are much much easier to clean. Think of your water storage tank as a long term investment. On occasion you will need to clean out your tank. Bugs, frogs and creatures of all kinds will try to get to the water source and sometime they will drown in your tank. It will be important for you to clean out your tanks to avoid bacteria buildup.