New well drilling, metal or PVC casing?

[oosik]

What does the PVC liner get you - #1 - less expensive than steel #2 - seals the well and water from layers of silt, sand or clay. The problem that can develop from the use of PVC - the drilled hole must be over-bored. Meaning a 5" PVC casing is installed in a 6" bored hole because PVC can not be driven like steel. Can allow "bad water" to drain to the "found" water table if not properly sealed off with grout or with some other method.

If you case clear to the bottom how does water get in - Remember wells are usually terminated is a strata containing ground water. This allows for almost instantaneous inflow of surrounding ground water. If anywhere acceptable water is found on the way to the bottom the steel casing can be "shot"
Its a tool lowered to the depth the water is found - an explosive charge will send lances out from the tool and perforate the steel casing. Allowing the water found at that depth to enter the casing. Once shot, the tool is pulled back up

In Anchorage, where I worked, it was not the least bit uncommon to have private well go to 400 feet and deeper

I don't know what is meant by having the driller "guarantee or warranty" the well. If you mean guarantee the the quantity or quality of the water - I have never heard of such a thing. They will run a production test and have the water quality checked - beyond that - what you get is what you get.

 

[Raspy]

if it is cased all they way to the bottom how does the water get in?

Perforated pipe is used for the liner below the water line. This allows the water to get inside the liner, acts as a screen to keep the well from filling in with rocks and strains the water that will be pumped. Silt can get through, but conditioning the well and giving it time will reduce or eliminate the silt. If the perforations clog, air or water can be pumped down to clear the clogged perforations. I would insist on a full liner all the way to the bottom. My pump is set 65' below the water line to be sure it will not pump the inside of the liner dry, in case it can pump faster than the water can come in through the perforations.

 

[Oldoak]

Having a little experience working along side of water well drillers, I know oosik knows more than most about well drilling and what it takes.

As for some of the residential and farm wells drilled in my area, the depth runs anywhere from 60' to over 700'. Not one that I know has a PVC liner and certainly not all the way down to 700+ feet. And there are certainly no guarantees.

By-the-way, my 325' depth well with 40' of steel casing drilled back in 1973 is still flowing fine with the original submersible pump.

 

[Cat_Driver]

I have two 8" well one steel that is rusted and flaking down about 240 feet about 30 plus years old. The other PVC down 550 feet ( to punch through the clay ofr better water) and the PVC look new like the day I installed it 25 years ago.

 

[3Ts]

I have a well 600' deep cased all the way down with PVC. It was first bored for a 4" casing but at 500' (i think) they had to go to a 4.5" casing to get a thicker PVC wall and keep the same inside diameter to fit the pump. There is no bedrock. The aquifer is 515' down and 80' thick. pump is set at 320', water comes up to 250'. They drilled to 500' the first day and no water, all expectations from records of previous wells were that water would be around 300 to 350'. There were no guarantees of any kind.

 

[Billrog]

There is good reason to run a pvc liner down even if it is bed rock. There are a no. of wells around this area in what was consider solid bed rock with none working pumps in the bottom of them because they couldn't be pulled. Liner serves as a means to keep loose rock from shifting over and restricting the size of the whole making pulling the pump in some cases impossible. If drilling a new well is the only option it can be very expensive.

 

[300UGUY]

I have a steel cased well. It was here when I bought the place. If I have to replace, it wil be pvc. I put in a new Grundfuss 3 inch pump, in the 4 inch casing. The well guy is selling a lot of them, it won’t seal up to the pipe. It is rated for the same gpm that the 4 inch pump was.

 

[Valveman]

Hopefully the driller has done this a few times and knows the best way. Everybody else is just guessing, even though they maybe good guesses. PVC won't rust out or rust up the perforations like steel. But some wells require steel because of the depth or problems with the formation. Use as large a casing as needed to put in a regular 4" pump because the little 3" pumps cost more and don't last as long. I like 5" PVC so I can put a 4" flow inducer shroud on the pump, as the shroud will make the pump last longer.

 

[DieselBound]

I've got a stainless steel (5'?) screen on the bottom of my (6") steel casing (well is only 38' deep). I believe that this install is 25 years old. If it ever comes to it I can sleeve with PVC.

 

[ch1ch2]

I壇 much rather have the pvc. It won稚 wear out in your lifetime, and the less rust in the system, the better. And if you need to work on the pump, it isn稚 rusted onto the casing.

Ditto