PVC Well Information... The use of PVC well casing for private water wells has been part of Wisconsin's Private Well Code (NR 812) since 1975, but many people in central Wisconsin have never heard of a PVC well! The primary reason is that much of the drilling conditions in this area require the use of 6" steel casing in any (bedrock) formation where the casing cannot be advanced. In the same code revision, the reasoning that went into requiring steel casing in bedrock wells was that, if a troublesome formation were encountered in the open bedrock formation below the casing, and you could not drive the casing further to seal off the problem area, a liner could be installed allowing the well to be completed without having to start all over. Furthermore, steel was required as there was concern that the trauma of drilling through PVC casing may damage it. Because of this requirement, many of the well drillers over the past nearly 40 years have optimized their equipment to construct 6" steel wells very efficiently.
There are many areas of Wisconsin that have sand & gravel formations over the bedrock. While some people choose to have 2" wells & jet pump systems installed in these areas or believe that they must have a 6" steel well, we believe that there are many advantages to a PVC well. Let's cover some of those PVC advantages:
AVAILABLE WATER SUPPLY and Expected Life Span (SCREEN):
In a sand and gravel formation well, you generally need a screen to keep the sand out. (Not all screens are stainless steel!)
The amount of water that can pass through the screen as well of the screens expected life span---or how long it takes to plug up---depends a great deal, among other things, on how much open area is available.
Your well will only produce as much water as is allowed through the opening at the bottom. If that is a screen, then you can see what an important element that is in your well! See here for more screen information (and a bit about the formations we look for).
Imagine a rectangle 3" x 9". That is about how much open area (in inches) you have in the screen in a 2" well. Shorter than a ruler, and not much wider.
"To Scale" Representation of open area in an average 2" Well
This means that if this square were actual size, it would be 8.99 inches wide and 3 inches tall equaling 26.97 square inches total for your water to come through.
All of these squares are relative to actual size.
Open area in our average 4" Economy Well
Compare to other drillers 6" wells.
Now Imagine a bigger rectangle 8" x 10". That is about how much open area (in inches) you have in the screen in a 4" economy well. Just a little smaller than a sheet of paper for your water to come through.
And you see that there is not a lot of difference!
Compare that to the open area in our average 4" Standard or Performance Well
Now Imagine an even bigger rectangle 12" x 14". That is about how much open area (in inches) you can have in the screen in our 4" Standard well.
You can get a lot of water through an opening that size.
Representation of open area in our average 4" Standard Well as Compared to an average 6" well.
Or to look at it another way...
Expected Life Span (CASING):
No chart this time! PVC is completely impervious to corrosion! PVC is not susceptible to common problems with Acidic Water, Iron bacteria, Ferrous or Ferric Iron, Soil PH, Bacterial Agents. Rust and scale that build up on steel casing will not happen with PVC. The scale that precipitates off and clogs your washing machine screened inlets and kitchen faucets simply do not happen with PVC casing. If you have any iron dissolved or otherwise in your source water, it is not complicated by the PVC casing!
In a well, you at least hope you have water, right? Any time you have water, air and steel, you are going to have at least some rust. Replace the steel with PVC and you have eliminated a lot of problems!
The Plastic Pipe and Fittings Association lists many benefits to PVC pipe on their web Site.
PVC wells are nothing new for some people. Between 2000 and 2008, 79%-83% of them 10,500 to 36,000 or so wells constructed annually in Michigan were PVC.
Have you ever heard that it is difficult to change a submersible pump in a 4" well because the pump gets stuck? In a STEEL well, anyway! That's because the pump is typically 3 15/16" in diameter, and inside of a 4" well that only leaves a little less than 1/10 of an inch all around the pump.
When the well casing begins to corrode & rust, it does not take a lot of build-up of scale to make it difficult to remove and replace the pump. Not generally IMPOSSIBLE but more challenging! PVC casing eliminates this problem! Decades from now, the inside diameter will be exactly the same as the day that your well was installed!
Furthermore, the way that a submersible pump is designed, the water must flow more closely past the motor to the intake of the pump. The closer tolerances that you have in a 4" well actually cool the pump motor more effectively by creating more water flow directly past the motor housing. This takes more heat away from the motor, rather like a car radiator cools the engine in your car! Since the greatest enemy of your pump is heat, this can lead to longer pump life!
Franklin Electric, a major manufacturer of submersible pump motors, actually recommends the use of an "Flow Inducer Sleeve" in 6" casing on some pumps to allow for adequate cooling of the motor. Is a 4" well, this is not necessary! See http://www.franklin-electric.com/media/documents/60Hz_AIM_06.pdf
PVC is easier and safer to handle, too!
6" Steel Casing= 440 lbs / 21' length
4" PVC Casing (SDR21) = 38.44 lbs / 20' length