Sorry to hear about your problems. I have had some recent experience with boreholes, having had 2 drilled in the past 5 years. (I had to have the second one done simply because the only place we could build a new house on the land was where the first borehole was sited.) Which brings me to your figure of 18K to put in a borehole. I thought my first one was pricey at 7K with all the electrics and submersible pump and accumulator tank. The second borehole only took a day to sink 50 metres (they can go deeper but that is the standard depth they drill even if water is only 20m down). We then transferred all of the kit (pump, etc) from one hole to the other and away it went. I'm sure that we only paid something like £2,500 for the second hole to be bored. Even if you double that for the equipment, that's still less than a third of the price you mention. I used a company called Teify Valley Water Wells (07817 35049) and I'd definitely advise at least talking to them to get a quote, because it could be an answer to your problems at a much lower price than you have been led to believe. I'm assuming you have power on site to drive the pump.