Yes, a tank can solve so many problems!
But in all seriousness, the water problem at that agistment place is fixable, and it is indeed easier to set up a tank than to live many miles inland if this isn't where you and your spouse really want to be, for yourselves - and I do actually, outrageously, think that decisions on where to live should primarily be about where you humans would like to live, not where your horses might prefer / do better - yes, you love your horses and their comfort is a factor, but it's often so much easier to fix your horse problems, than to fix problems you have as human beings because you lived somewhere that wouldn't have been your own first choice if you didn't have horses.
So make sure your own work, social, cultural and non-horse-recreational activities are addressed first, by where you choose to move to - and then you'll also be in a better position, financially and emotionally, to take care of each other and your horses.
We moved just 25 minutes' drive out of Albany to where we live now, and the horses are on our own property etc, but that wasn't the main reason we wanted to move here, plus also, I would never have moved far into the sticks just to keep horses (of course, if I was a person who enjoyed living far out in the sticks, that would be different). We were actually, when we were moving, seriously looking at living in Denmark, a small coastal town 30 minutes from Albany - it's a nice hippie town with lots of bookshops and other shops run along ethical lines, and a lot of community activities, and most people not materialistic, and lots of thinking outside the box, and I would have loved to live in a community like that. But, property prices there were through the roof. We did make two offers on houses for sale, neither of them at the listed price because people were asking more than new-house prices for rather neglected houses that needed a lot of work. The offers were both rejected - with the second one in particular, we were pretty sad about that at the time, because we could have pictured ourselves living in it happily - it was a very unconventional house, in a lovely situation. But, it was also a very cold house in winter, and as it turns out, the house we live in now is so much better in so many ways than the houses we made offers on (of course, this meant putting five years of our spare time into building it ourselves).
The reason we bought where we did is because it was a once-in-a-lifetime opportunity for us to live on an actual farm, that was still within a reasonable commute to work and places of cultural and recreational interest, and was never going to be swallowed up in developments and urban expansion. The drawback is the commute, and another that it's not a particularly great local community, unlike Denmark would have been; and even though I'm only 25 minutes away from all the facilities and community groups of Albany, where we lived before, I simply don't end up driving there to do Pilates or choir or whatever else I would have done if it was 5-10 minutes away, and I don't see my friends nearly as often as I used to. But neither of us have regrets about this, because at least if it became really important to us to do these things, we could find a way to do them again; and because there are so many compensations living out here at our place.
And our weekends are just as filled with hiking now as they were before we moved out here, on the same trails, because that's an easy thing to do from here; and we often grab a coffee or a kebab going through either Albany or Denmark on the way to a nice walking trail, so that we multi-task some social and cultural activities alongside our beloved walking.
Swings and roundabouts. But, yeah, I'd never have moved 100 km from Albany or Denmark to do what we did. We don't care about being 400km from Perth because we don't like that huge metropolis and don't need anything from it, but it's great being close to a good settlement with services, really good cultural amenities etc.
And also I'd never have done what I see so many horse people around our local area do - which is to move to some place just because they had horses, and then build these elaborate stables and horse facilities, and live in a cheaply built and not very comfortable little cardboard house themselves, just so they could have horses at their place. I'd rather have agisted, or not had horses at all, than do that; and especially because my husband isn't horse-mad and it's not his hobby, so I didn't want one of my hobbies to have an excessive impact on the way he was going to live for the rest of his days. A lot of talking went into the decision to buy this farm and move out here, and I would never have done it if I thought Brett was just going along to do me a favour because of the horses - we both had to want to live on this place for our own reasons - and I'd leave here in an instant if I thought Brett was getting unhappy out here, but thankfully (because we've both invested so much of our sweat, blood and tears into this place), we both still love it, and can work around the compromises of living here, which are, for both of us, outweighed by the positives of the place.
But having seen what my parents did, and the way that they tied themselves to their hobby in a way that was really destructive of family life, personal growth and wider experience, and didn't take into account democratically the dreams and welfare of everyone in the family, and how everything revolved around the horses and the people were second to the horses, and how the horses got shoved into expensive buildings they didn't want to be in and the homestead was left to deteriorate and fall apart because people were always too busy mucking out stables and walking excessive numbers of horses in and out of little feedlot paddocks and feeding them four times a day and obsessing about racing these animals and winning races (Brett thinks the whole thing was basically psychologically like a gambling addiction) - well, I would rather have given up horses altogether than live in anything that remotely resembled that kind of set-up.
So we live in a nice house, and our horses free-range over pasture largely feeding themselves, and get rugs on when it's cold, wet and windy, and people and horses are all happy this way, and much happier than the people and horses at my parents' place. And that's the irony, that you can't quantify your love and care for your animals by how much money you spend on them or how much of your own life you give up for them mucking out buildings they don't want to be in and bringing them their every meal - just as this is no measure of love and care for people. It's actually a narcissistic kind of "love" which is more about "look how much I do for them and how good I am" than healthy love, which is about, you know, teaching a man to fish instead of constantly giving him fish, which is about looking at the real needs of the people and animals in your life and catering to social and emotional needs in people, not just the physical, and ditto for your animals, and yeah, letting your horses have a more natural and independent sort of life where their social and exploratory needs are better met than when you lock them up in buildings. I realise we are very lucky here with being able to do that for our animals because we have a lot of space, but the agistment I had my mare in, in Albany in 2008, was also that kind of facility: Horses got most of their calories from grazing, and lived in a little herd, and had room to roam over large pastures, and lots of natural shelter, plus we rugged in the cold, wet and windy periods, and the proprietor would take rugs off horses in the morning for a sunny day, so you didn't have to come in twice a day to tend to your horse in rugging season.
Well, I certainly got reflecting this morning, and I hope that's been of some use to share that!
Keeping my fingers crossed that you'll find what's right for all of you.