I am in no way trying to start an argument and I apologize if this post comes across this way.
A question was asked
As a matter of interest, will stored water keep forever, or should we empty it and refill every six months or so?
I would like to know the answer to this.
But in the same post
In such a scenario I envisage camping by the side of a river somewhere like this pic where there's all the water I need, sewage can also be slung in there to be carried away by the current.
Then the same poster less then 3 hours later said
Screw the harbor, I plan to set up my solar still out beyond the lock gates along the fresh coastline
How do you expect to get the answer to your question when jumping all over the place like this? Are you just responding to posts or do you have a plan?
First:How many like minded people are "slinging" there sewage up stream?
Second: Fresh coastline does not exist. Where do you think all the factories, cities and like minded people dump there waste? How many times have we been told to only eat fish once a week due to the mercury content? In the event of an emergency I expect it to be even worse. The majority of the natural disasters we have experienced recently involve flooding. This flooding causes the sewage treatment plants to over flow, dumping untreated waste into the environment, which by the way is almost always next to a stream
New Orleans with Katrina; Mississippi river flooding effecting Missouri, Illinois etc; N Dakota (Fargo?) when the winter snow melted to fast, two years in a row; and lastly Sandy flooding how many states? These people had to leave or face a life threatening situation leaving most of their prepping behind, if evacuated, leaving all of it behind. In the later case that leaves you with the cloths on your back and your wits. In any situation it's your wits that will keep you alive.
All these situations I mentioned there was plenty of water but it was undrinkable due to sewage plants over flowing there treatment pools, fertilizer/pesticide run off, and in the case of Sandy it left behind an oily film.
When hurricane Isabelle came through I was bugged out to keep the Air Force running in preparation for the worst. Turns out the base was completely underwater during the storm. I returned 2 weeks later. My house however did not have electricity restored for 6 more weeks, water and sewage was not interrupted. The base is apx 10 feet above sea level and it was 2 feet under water during the storm. No treatment plants were compromised, however how many under ground fuel tanks were? Upon my return, the first night, I noticed a car full of teens driving up and down the roads shining flash lights on the houses looking for open windows and such, hmmmm. It was hot and muggy so with no electricity, the windows had to be left open. This was the first time I ever kept a loaded gun near by.
I was lucky, I was in the Air Force at the time and had resources at my disposal through that avenue. I could take a shower at the base gym if needed, recharge flash light batteries while at work etc. Now I'm a civilian and have to do all my own planning with out relying on a resource like that.
My house has a 50 gallon hot water tank. By shutting off the main to the house that will not get contaminated. I do not have the space to store large quantities of water so I'd have to forage. If no flooding was involved I'd make seep holes and use other means to collect water. If flooding was involved, collecting rain water would by my main option.
Sorry for such a long post. Main thing I'm trying to say is use your head. It is what will determine your survival.