Old well for water storage
 

There is an old well behind our house. It was built a long time ago, and the last time it was used was 40 years ago when the house was being built. I uncovered it yesterday and saw that for the first 2 meters (6.6ft) down it's just an empty cavity, lined with concrete rings 1 meter (3.3ft) across. There is also a pipe going up on one side. I asked Dad-in-law and he said that the rings go down a little bit deeper, but it's all sand below that. The pipe goes down to 18 meters (59ft). The ground water here supposedly had a lot of iron in it and the pipe and water filter at the bottom rusted over pretty quickly.

So we have 3 ideas for what to do:
1) Dig/drill who-knows-how-deep and use ground water for watering the lawn. I'm not sure what state the ground water is in (a few neighbors still have septic tanks, and many of them wouldn't be happy if their tanks were water-tight), or how deep it is. Dad-in-law said that when he started building the house in the 1960's, the waterline was around where the foundation started (1.5m/5ft), but soon dropped below 2.5m (8ft). Since then many other building have been built nearby, so there would be quite a bit of digging. Plus the waterline in our sandy soil drops during droughts when water for the garden would be needed the most.

2) Dig until to bottom of the concrete rings and use the cavity for storing rainwater (the well is only 5m/16ft from our rain gutter). Having 1500-2000 liters (400-520 USgal) of underground storage is unquestionably better than three 220 liter (55 USgal) barrels standing under the gutter. Of course, anything poured in at the moment would just sink into the sand, so the well would somehow have to be made watertight. Any ideas? And would the water freeze in the winter?

3) Use the well as a good starting point and dig/drill some more to have a ground source for future heat pump use. Knowing that the pipe extends down to 18 meters is tempting, but it's worthless at the moment.

Any other ideas? Maybe there could be more than one use of this old well?

Interesting. I'd probably opt for #2. You can get a liner of some sort in there so it holds your water. When winter rolls around you could just pump most of it out so it doesn't wreck the concrete.

I was wondering about the liner - should it be some soft rubber/plastic, like a big garbage bag, or stiff plastic, like a huge bottle? The latter would probably be less likely to leak, but would be harder to find in a size that uses the available space most efficiently.

Anyway, I grilled the family today (the Wife's older brother and Dad-in-law again) and it turns out that there are more "buried treasures" in our yard. First, in the front yard where I park the car, there is an old concrete septic tank that had been converted to a so-called revision well when the sewer system got connected to the house. (The revision well is to see how things are flowing in our sewage pipe. I refrained from posting pictures of what we found inside;)) There is a second revision well closer to the house, this one is also off limits to my ecoprojects.

My bro-in-law remembered that there used to be another septic tank off to the side, but Dad said it's buried deep under the grass. But after pestering him with more questions and being a PITA he finally admitted that it is now disconnected from everything, so could possibly be used as a water tank. Of course, finding it and then working on it would ruin his beloved lawn (which, btw, the dog is independently doing his best to ruin anyway). Bro-in-law says that he remembers yet another old septic tank somewhere close by, Dad told him that his memory is getting carried away.

Either way, being surrounded by all these septic tanks and revision wells, I feel that our house is standing on sh*t;)

So, if the there really is an old septic tank under the front yard, and if it can be cleaned out and will hold water, then it would be much larger than the old well in the back could be converted to. Of course, this is all very iffy, plus the roof would have to be reguttered, since the septic tank is on the 'wrong' corner of the house. Then the old well could be used in some other way, so we are still open to any ideas.

What about the liners people use to make ponds for landscaping? I have seen huge ponds installed so I imagine pond liners of all different sizes are available. Might cost more than it's worth though. An other thing you'd have to think about is how are you going to get the water up out of there? Solar powered pump? Hand pump? Those are probably readily available. You could probably find dozens of them at any yard sale. And to power it you just make some children. They are easy to make and they surely have enough energy to power a hand pump.

A hand pump is exactly what I had in mind. I wouldn't want an electric pump as that might get abused by users.

I can't disagree with that;) But I think that globally I'd end up putting more energy, resources, and nerves into the kids than I'd get out of them (if that was the only reason for making them)...
Plus it's a long term investment - it'd be at least 3-4 years before they can be made to do something productive.

Your well won't freeze - we have a similar well used for household use ( I don't like the idea of drinking water that's had dead mice in - yech) and it won't freeze as the warmth of the earth keeps it above freezing - geothermal technology! We have a shed with one light bulb going all winter to stop the pump and pressure tank from freezing, but the water itself never gets that cold.

I've been looking around for something to put inside the old well to hold water and I've found three possibilities:

1. There are plastic revision wells for sewage and/or other underground media. They come in sizes which would more or less fit, but they are prohibitively expensive, mostly because of the certificates they are required to have.
2. Steel pipe, 90cm diameter, used for steam in an old factory. Not very cheap (worth more than just its value at a metal scrap yard), and very heavy (12mm thick walls). Welding on an endcap wouldn't be as much of a problem as transporting and installing.
3. Plastic sewage pipe, 90cm diameter. 10x cheaper than steel pipe and much lighter. Problems:
   • If I made a 1.5-1.6 meter tall cylinder out of the PVC pipe, then will the walls be able to handle the water pressure? I could pour sand in between the pipe and the well's wall to help distribute the pressure from the outside, but would that be enough?
   • How to make an endcap for the bottom so that it doesn't spring a leak under the weight of a 1.5 meter column of water?

Have you considered a paintable liner?

With sand filling the space in between the plastic and the well wall I'd imagine it would work just fine. The walls on my plastic 3500 gallon tank weren't very thick. and it was 8' tall. No idea how you'll cap that though.

Too much hassle, I'm afraid. The well has no bottom, ie it's just sand, so I'd have to pour a concrete "floor", then waterproof that and the sides. The sides are concrete rings with lots of space between them, so the waterproofing would have to be somewhat elastic. I believe that around here the standard material for waterproofing concrete septic tanks is tar, but maybe some new products have come out. Any suggestions?

Of course, if waterproofing wouldn't be too hard and/or toxic, then that would be ideal, since it would allow me to use the full width of the well.

I've asked twice at a local builders' forum for suggestions, but no-one is interested.