facts, opinions, hard data and some WAGs welcome. . .

For resi. wells, what percent of drillers get a usable well on the first attempt?

What is the lifetime of a resi. well?

If your working well is 200' deep and your neighbor has a working well, how shallow or how deep is it likely to be?

Thanks, folks. . .

Around here I would say about 90% + on hitting water, first time. Thats what they pay the geologist the big bucks for.

Depends on where you live

Depends on the aquifir depth

my area of NE FL is 100% chance, go deep enough and you will hit water. usually 2-3 different zones here you can pull from. we normally get wells from 40-160' (rock well), 200-380' (intermediate well- "salt&pepper"), 480-700' (artesian) .. just depends on what type of water they want and how much they wanna spend. but just because there is an abundance of water doesnt mean NE FL drilling is easy, we have to fight with "cave-ins", sand, bad clay, shell, gravel, etc.. .. on top of the fact that we are mostly low-land, so its always muddy and nasty, and hot.

here most close neighbors will have same well depths within 10' or so. although there are those few places we have drilled wells within 50' and they be totally different in terms of rock formations and well volume. i've even drilled a 100' rock well at one house, then there be no rock at his neighbors and have to go 260' to get to the next zone. can sometimes vary alot in a short distance.. the key is knowing where these uncertain areas are.

thats what makes well drilling so unique.. changes so much from area to area. any pinhead can work hard and operate equipment, but if you dont have enough experience to know what to expect here and there within your area, and how to prepare for it, you will have a very tough road as a new well driller starting out. running the equipment is the easy part.

a pvc well here that is drilled correctly "should" be the last well you ever need..

Thanks, guys, that is exactly what I'm looking for.

With 90% chance [0.9] of hitting it the first time, with two wells you go to 1-(0.1^2) = 0.99 = 99% chance. Based on this I'd say if the driller can't hit it with two wells there's something seriously wrong or his number came up.

My impression was that it was a lot more iffy.

It depends on the area of Maryland. Around Frederick I know some have drilled six and more holes to 200 feet and more and got no water. Depth required is where you find water. Find a reputable licensed and hopefully NGWA Certified Driller and good luck!

Porky said:

some have drilled six and more holes to 200 feet and more and got no water.

Click to expand...

Approx. what percent of drillers have such an experience?

What's the rule of thumb for when to call it quits?

Some areas in our part of the country have 100% chance of finding water. I can even tell you almost exactly how deep the well will be. In other areas it can be 50/50. And in some areas it is less than 5% chance. As justwater and Porky said, the experience to know where these areas are is key. There are more well records available than there use to be, which helps. But there is still no substitute for a driller’s experience.

I e-mailed these guys
http://www.ngwa.org/
we'll see what they say.

But, in addition, can anyone recommend textbooks on the subject of residential well drilling?
In a search of the whole MD library system I only got one hit, and that is dubious.
Possibly the local community college has a tech. bookstore and they may have something.

Ngwa should probably be able to point u toward literature on fundamentals of well drilling in different parts of the US, but I'd guess it would be hard to find much past that.

In my experience, well drillers aren't really known for their generosity in sharing information of drilling methods/techniques.