Since we live so close to the Gulf (it's only 1 block from our house and we walk over to it all the time) I thought it would be a good idea to start teaching the boys about desalination. I looked up some DIY water desalination plans online, and found that's pretty easy to do on a small scale.
It's actually very easy, even on a large scale if you're right on the water, which, once we build our boat bikes and sailboat will be useful for visiting our barrier islands for weekend survival lessons and exercises, or if we ever find ourselves living right on the water again.
The process is very simple reqiuring only two containers, a piece of plastic or other waterproof material, and small rock or marble, and a rubber band. The saltwater is placed in the larger of the two containers. The smaller container is then placed in that larger container. Make sure to only put enough water in the larger bowl so that the smaller one will not float. Cover the larger bowl, with the plastic and secure the rubber band around the outer edge of the bowl. Place your rock, or marble, on top of the plastic above the smaller bowl so that make a 'slope' so that as the water evaporates and condensation collects on the plactic, it will 'flow down' into the smaller bowl. Place the bowl in direct sunlight for several hours and you will have desalinated water.
Here's a video that shows the same process being used to distill water...
Depending on condensation for desalinated water won't produce large amounts of water. We can elect to collect as much as we can carry from the river to home (possibly with some kind of wagon pulled by a bicycle) and doing this process at home on as large a scale as we can manage, maybe even using solar power to speed up the evaporation process to collect more condensation, but two things come to mind. The purpose of this is to teach our children how to do this should the day ever come that they must do it. The other is the idea of also using cisterns to collect and store rainwater for irrigating our crop.
If a cataclysmic event ever forced us to take to the sea, or squat along a shoreline, we would be able to create drinkable water from the sea.