Ask the neighbors where they hit water with their wells. You should be able to then determine the water table in your area. There are exceptions but typically a pattern will surface and you should have an idea of what to expect.
700 ft? Only if you're in an unusual place (very arid or high). Wells that flow enough water for personal use should be 40 to 200 ft down in areas that get 48 in (plus or minus) of rain per year. Sometimes drilling is not required. In low elevation with high water tables and soft dirt a shallow well can be punched. Drilling can be difficult depending on what's underground (like rock) and may require very expensive equipment to accomplish what you want. Often your neighbors well will give you an indication of what you can expect but not always. (A friend of mine drilled a well and got less than 2 gal per minute. His neighbors well about 300 ft away yielded over 20 gal per minute. Also be careful some states require permits and only licensed drillers are allowed to drill.
Location: Southern Illinois rather be back home in Kentucky.
I've seen advertise a DIY well drilling rig. I don't remember how it really work buy I would bet it wouldn't be as expensive as paying someone to come in with a huge rig and dig it.
Try googleing dig your own well.
If you go to those sites they are onlt talking about 5 to 6 lengths of pipe too. And sure you can pound down one on your own, But even with 6 lengths of pipe at 20ft each that is only a 120 feet well. The poster is asking how to drill a well that is 700 feet down??? No way are you going to do that by yourself.
My family has been in the water well drilling business since 1856, and nope not that far, not even close to that deep. 125 to maybe at best 150 foot down but that is about it. Unless you can buy a used machine powered well drilling outfit.
I used to have a Deep Rock well drilling outfit. I drilled our well at the place we had then, around 1975 or so. My first well was only about 50 or 60 feet deep, mostly through limestone and shale--lots of work even though it wasn't real deep. A friend used it to drill 2 more wells, 120 feet and over 150 feet. A few other people used it too, and then I sold it around 1990. Wish I still had it. It worked okay, saved us lots of money. It drills an inch hole which you ream out to 3" or 4" (it has been awhile, so I don't recall the exact dimensions) and then you used a small diameter casing. We then installed a small diameter pump cylinder and a hand pump. It all worked fine, just lots of work as it drills slowly, and you need water as a lubricant while drilling. I think that one of the time consuming parts of our first well was hauling barrels of water from a neighbor's while drilling.
I get 40 or more inches of rain per year. My well was dug to 750 feet, $11.50US per foot. Well depth has a lot more to do with topography and geology than rainfall. Unless you have a drilling rig, if your neighbors have deep wells, I think you should look for a professional to drill yours as well. Contact your applicable county agencies to find expected well depths and licensed contractors.
I would agree with the others that say get a professional. If the well driller is reputable, their estimate should be fairly close. If the neighbors say its much shallower, get an estimate from a different driller.
I researched drilling our own well in Wisconsin. I even went so far as to buy an 8" drill head. We ended up getting it professionally done. 295' depth, 187' of casing. $12k
Again... where are you located? In the midwest for the most part there is no problem drilling anywhere you want for residential water. Out west, however, its a different story. In Wisconsin EVERY well needs a permit. You can dig/drill your own well, but it needs the permit. There are standards that have to be met, minimums for casing material/size, etc.
I was going to build my own drill to save money. The costs just kept adding up. The 1" drill pipe that the typical DIY drills come with don't handle 8" bits. In WI, 6" pipe casing is the minimum, so absolute minimum of 8" hole is needed. 2" drill pipe alone was going to be several thousand dollars for the amount I needed. The wimpy little engine on the DIY machines would have a problem with the limestone my well is on. The other problem was the limestone was fractured. When they tried to grout the casing, the neat cement just flowed away through the cracks. If I had tried my simple water lubed drill, it would not have worked, or gotten rid of the waste material.
The company that came out spent 3 days at the property. One guy with the main rig and tender. Pneumatic rotary drill, large diesel engine that ran full out for the 3 days. Since they knew the area (95% of the counties wells were thiers) they knew how to get around the problems.
I would say that if you need a shallow well (under 200' as others have said), have soil/soft rock that you can get through, you might have a chance. At most I would say that you will save a max of 50%, and may end up having to pay for it to be done anyway. If you know someone with the equipment already, then its a much better bet.
If your well is double of ours, and even if it only costs you 25%, you still are looking a $6k. Can you gamble that on how good you are? I think the minimum cost is going to be closer to $8k-$10k, even if you are successful.
I own one of the Deep Rock Hydra-drill rigs. It cost about $5K about 7 years ago. It has more than paid for itself in the several wells that it has drilled in that time. It has been used to drill wells from 30 to 180 feet with varying amounts of success. You would need a much larger rig to even begin thinking about trying to go down 700 feet. All of the wells that it has been used to drill have been in clay with sand or gravel layers that hold the water. I wouldn't even begin to think about drilling through any real distance of bedrock, even with the right type of bit - it would take forever.
If you have to go to down 700 feet to find usable water, you're wasting your time looking into a DIY drilling rig.