Pitless Adapters for Steel Casing Water Wells

What is a Pitless Adapter as Used on Water Well Casings?

The pitless adapter is a special pipe fitting that connects the vertical drop pipe in a drilled well casing to a horizontal exit line to bring water to the building or end use destination. The adapter makes a water tight seal between the round steel well casing surface and the well pipe that has to connect to it.

As the name "pitless" suggests, this special fitting allows the well pipe to exit the well casing underground, eliminating the need for a WELL PIT, well house, or to bring the well pipe up to the ground surface through the well casing top.

In freezing climates, to avoid a frozen well pipe between the well and the building it serves, it is important that the water pipe leaving the well to carry water to the building is buried below the frost line.

A special fitting, the "pitless adapter" is used to seal the passage cut into the round well casing to permit the water piping to pass through the casing and out to the building it serves.

Pitless adapters like the ones shown here can be used on well casings that are typically 4" or larger in diameter, up to about 12" in size.

Smaller diameter well casings will need a clamp-on or other type of adapter like the Merrill SPK406 (illustrated below on this page) to connect the horizontal well pipe to the well pipe inside the well bore.

Larger diameter well casings will generally use a spool type pitless adapter that is also described in this article.

Our photo at page top and our drawing just above shows examples of uses of a pitless adapter.

For the artesian well (in our sketch just above) a low-pressure well spool using a clamp-on pitless adapter in a design suitable for artesian wells whose head pressure is equal to or less than 5 psi (a head of 11.5 ft.) - courtesy Michigan DEP. Similar pitless adapter fittings accommodate other well casing and piping designs.

There is a variety of types of pitless adapter fittings, of which for steel casing water wells the most-common is the slide type pitless adapter that allows the vertical well pipe to be connected or disconnected to the pitless adapter by carefully raising or lowering the vertical well pipe from above.

Later in this article at SLIDE TYPE PITLESS ADAPTER PARTS & DETAILS we show the exact parts of a slide type pitless adapter, making it more obvious how you can pull the well pipe out of the well while leaving the through-casing horizontal connector and seal in place.

Other clamp type fittings used at the top of a well casing may be used to seal the well top around piping that exits at the top rather than the side of the well casing.

This approach is suitable only in non-freezing climates or where the well head is protected from freezing by its location such as in a well pit or inside of a heated structure.

What's cool about most pitless adapters used on water wells is that inside the well casing the component of the pitless adapter that attaches to the top of the well piping is designed to simply slide up and out of the remaining pitless adapter parts bolted and sealed to the casing side.

Below you can see our photo of the slider half of a pitless adapter having been pulled up out of the well. The lift pipe is the galvanized pipe above the pitless adapter.

The actual well pipe and at its bottom, the submersible pump are attached to the under side of the pitless adapter and are not yet in view.

This slider feature is what allows us to pull the well piping and submersible pump or foot valve completely out of the well without having to dig up and expose and disassemble the pitless adapter from outside the well.

This well installation was in Two Harbors, Minnesota where the freeze depth can be so severe that many installers put the pitless adapter eight feet below the ground surface to be sure it and the exiting well piping are below the frost line.

This pitless adapter was not leaking, but this is a place we'd check for leaks if we were looking for a leak in well piping.

See WELL PIPING LEAK DIAGNOSIS

Parts of a Slide-type Pitless Adapter for Wells & How they Work

Below, using a 1-inch 304 Stainless Steel pitless adapter sold by AquaScience.net for about $80. U.S., we can see the parts of a pitless adapter more closely.

Naming parts from left to right beginning with what's inside the well casing:

(The illustration above is our annotated version of a pitless adapter sold by Aquascience.net for about $80. U.S. - cited at CITATIONS & REFERENCES)

1. This is the removable part of the in-casing side of the pitless adapter.
   
   To the top of this fitting is screwed a lift pipe, also referred to as a "pull pipe" or "drop pipe," to permit the pitless adapter and well piping to be raised or lowered into or out of the well.
   
   When the well pipe and pitless adapter part #1 are lowered into the well the installer slides this fitting into part 2.
   
   To the bottom of this fitting the well water supply pipe is connected (blue arrow pointing up) to permit the submersible pump to send water up to the building.
2. This fitting is bolted inside the well casing during installation and sealed against the casing wall by gasket 3
3. The pitless adapter gasket seals between parts 2 and 4 to permit the curved parts to seal against the curved interior and exterior of the round steel well casing or "pipe"
   
   This is a two-part gasket, one fitting against the inner surface of the well casing, and the second fitting against the outer surface of the casing.
4. This is the external fitting mounted to the outside of the well casing and curved to mold itself and the gasket (3) to the well casing exterior wall.
5. This is the tightening nut that screws against the threaded pipe nipple end of part (2) to tighten the parts together against the well casing wall.
   
   The water service line (pipe) that continues into the building is connected to the exposed male threaded end shown in our photo where the blue arrow points out the direction of well water being pumped to the building served by this well.

Pitless adapters are sold in other designs but all work similarly to provide a water tight seal between the below-ground pipe connections to the well and the rounded surfaces of the well casing.

On larger diameter well casings, instead of using the slide-type pitless adapter shown above, the well installer/plumber will use a spool-type pitless adapter (shown below).

Both types of pitless adapter permit easy installation and removal of the well piping.

Examples of Pitless Adapter Manufacturers & Types

Sources for the pitless adapters shown here are listed in detail at CITATIONS & REFERENCES at the end of this page.

Top Sealed Well Casings: well pipe exist without a Pitless Adapter

Well Casing Top Clamp Fittings Seal Around Well Piping, Wiring, Vents

Other clamp type fittings used at the top of a well casing may be used to seal the well top around piping that exits at the top rather than the side of the well casing.

This approach is suitable only in non-freezing climates or where the well head is protected from freezing by its location such as in a well pit or inside of a heated structure.

Our photo above shows a top-sealed well casing that is designed to permit a single well pipe and some wiring to pass out of the top of the well casing.

This well was located indoors in a New York home - not a great idea - in the building basement. From what we see, a single water pipe exiting the well and wiring entering the well, we expect to find a submersible well pump installed here.

Our second photo (above) shows how a compression type well casing top seal works: bolts tightened through the outside top of the seal compress a rubber gasket between two steel plates.

The expanding rubber gasket seals around pipes, wiring conduit, or whatever fittings were designed to pass through this well cap.

This well casing top was installed in Two Harbors MN.

Below we illustrate a conventional sealing well casing top cap used where only electrical conduit must enter the well casing above ground. At this well the water pipe exits below ground using a pitless adapter.

Also see SUBMERSIBLE PUMP.

Leaks at the Pitless Adapter on a Well Casing

Galvanic corrosion of plumbing parts led to leaks at pitless adapter on our well

My water line out to the well casing became leaky to the extent that water continuously flooded the area near the casing.

After digging down past the pitless adapter a leak was revealed at the junction of the brass nipple to the coupling going into the pitless. Corrosion was clear on the brass pipe fitting but not the coupling.

I took a look on the galvanic chart to consider what the effect might be on brass (pipe fitting), silicon brass (coupling) and iron (well casing).

It appeared to me clear that the brass pipe was lower that the silicon brass on the corrosion chart and was therefore going to give itself up to corrosion to protect the silicon brass.

I think that the thing to be learned here is to be sure to use silicon brass in all parts between the plastic pipe and the well casing. Otherwise the problem is likely to repeat itself. - On 2018-08-23 by George Schwartze -

Reply by (mod) -

Thank you for the important and interesting point, George, I'll be sure it's kept with the article here and in our article series on galvanic corrosion of plumbing parts.

I suspect that since brass coupled to silicon brass should work without significant galvanic corrosion, that water chemistry in the soil or in the well was a factor.

See GALVANIC SCALE & METAL CORROSION

You might want your well water tested for aggressiveness - get its corrosivity index.

Let us know what you find.

Pitless adapters differ for steel vs plastic well casings?

is there a difference between a steel and plastic casing pitless adapters - On 2018-02-04 by salli -

Reply by (mod) -

Other than the obvious difference in materials I would not expect a plastic pitless adapter to be used with iron or metal well piping

Freeze-up Problems at Pitless Adapter on Water Wells

Why does my well freeze at the pitless adapter in very cold weather?

My well line freezes at the pitless adapter every time it gets 0 or below.

I pour a gallon of warm water down the well to thaw it out and it works fine until the next night.

If I put a heat tape on a piece of pipe and let it down to the pitless it wont freeze.

Is there a reason this is happening, no one else I know has this problem, is there something I can do permanently to fix the problem. thanks On 2017-12-29 by Dan ONeil -

Reply by (mod) -

Most likely your pitless adapter is not below the frost line

How do I protect the well water piping in the well from freezing?

When draining the water from a dwelling that is allowed to freeze, how does the water supply from the submersible pump, supplied with foot valve, drain so the at or above grade pipes don't freeze and break? - Nate

Reply: well piping and pitless adapter should be below the frost line

Nate: see these articles on preventing well piping freeze problems

• DRAIN BACK & SNIFTER VALVE SYSTEM COMPONENTS - drain-back systems remove water from well piping that might otherwise freeze
• PIPE FREEZE-UP POINTS - where water supply systems tend to freeze-up
• WELL PIPING PITLESS ADAPTER - permit well piping to exit the well casing below the frost line - provided that the actual installation depth really IS below the frost line for your area
• WELL PITS - are also sued to keep the well head below the frost line

Freeze protection for the submersible-pump well: in a modern submersible pump or even jet pump drilled well with a steel casing, the water line exits the side of the casing below the frost line (through the pitless adapter). The well piping too, should be buried below the frost line. If well piping is too shallow, indeed it may freeze up in very cold weather.

Water piping exiting older wells in some areas were protected from freezing by constructing a well pit that kept the well head far enough below the ground surface to avoid freeze-ups. But well pits can still permit a freeze-up in prolonged and very cold weather.

Operators & owners of buildings served by well pits typically provide a small heat source in the well pit to keep temperatures above freezing. Sometimes a simple light bulb is enough.

More tips about protecting a building from freeze damage are organized at WINTERIZE A BUILDING.

Do I need a pitless adapter on my well if we are not in a freezing climate?

Do i need a pitless adapter for a well is in a non freeze zone? On 2017-12-12 2 by CM -

Reply by (mod) - yes if your well pipes exit the casing underground

CM

Yes IF your well pipe exits the well casing underground.

No if your well pipe exits the casing at a casing top that is above ground.

Well Casing Hole Saw Size & Type for Installing a Pitless Adapter

What's the best tool for cutting the well-casing hole for a pitless adapter?

What happens to the metal filings when the hole is drilled for the pitless adapter?

What is the best hole saw to use for drilling a hole for a pitless adapter ? (Apr 28, 2016) George

Reply: details on drilling the well casing hole to install a pitless adapter

George:

My OPINION is that any of the more powerful drills will work fine for cutting the pitless adapter mounting hole in a well casing for a one-off job.

But on some projects where we had a lot of heavy drill work I found that a more lightweight drill (I'll skip naming the brand/model) burned up in one day.

So if you were a well installer or plumber who had to do this job more than once, I'd prefer a heavier duty drill like the Milwaukee M18 (fuel) or the (expensive) Milwaukee SDS-MAX (needs to plug a line cord in) or similar models. Those prices range from about $250. to almost $700. U.S.

Now about the hole saw itself, Boshart (in Citations) provided a table of metal bit hole saw sizes depending on the pitless adapter model which in turn depends on the drop pipe diameter -

Milwaukee metal cutting hole saws range in cost (using a 2 1/2" hole saw as example) from about $45. to $135. U.S. - cheaper if bought in a set but darned if I could find a set that matches the hole saw diameters listed below from Boshart. You may have to buy some of those sizes individually.

Casing hole cutting tip: since you're going to use a center punch to mark the correct drill location for the pitless adapter location on the well casing, I'd use a hole saw with its center guide-bit installed. Without that you'll find that the saw bit will jump all over the place as you try to drill the hole.

Excerpting from Boshart, here's a pitless adapter hole saw size chart:

Pitless Adapter Hole Saw Size Chart (adapted from Boshart)
Pitless Adapter (Drop Pipe) Size	FITS ALL WELL CASINGS 5" to 12"	HOLE SAW SIZE (in)
1"		1 3/4"
1 1/4"		2 1/8"
1 1/2"		2 1/2"
2"		3 1/8?

Notes to the table above

• Original source: Boshart Industries, How do I properly install my Pitless Adapter? (Website) Boshart Industries, 25 Whaley Avenue, P.O. Box 310, Milverton, Ontario N0K 1M0 Canada Tel: 800.561.3164 - 519.595.4444 Web: https://boshart.com/
  
  U.S. Contact: Boshart Industries LLC, 3601 Woodpark Blvd. Charlotte, NC 28206 USA 1.800.561.3164
  
  Notes: pitless adapters made by other manufacturers may specify different hole saw sizes. Also, note that Boshart sells only to wholesalers and retailers, not direct to the public.

Well Casing Pitless Adapter Hole Drilling Procedure

Here are details about the actual use of a hole saw to drill the opening in the well casing to install a pitless adapter, excerpting from PITLESS ADAPTER for SUBMERSIBLE PUMPS, Installation Instructions [PDF] (Friessen Drillers Website),

Mark the location of the drop pipe fitting neck on the well casing, drill the pilot hole, and cut the casing with a 60mm (2 3/8 in) diameter hole saw. The hole should be at a right angle to the discharge pipe and a minimum of 2.5m (8 ft) below the ground surface.

Using a half round file remove the steel burrs to smooth both the interior and exterior of the hole in the casing.

DF Continues:

A bit of metal debris probably falls into the well when the pitless adapter hole is cut using a 2 3/8" (60 mm) metal-type round diameter metal hole saw.

Provided the pump is several feet or more above well bottom (as is normal to avoid sucking up mud and dirt), that debris ought to be harmless.

According to Merrill who produce pitless adapters and kindly publish pitless adapter installation instructions, the usual installation procedure follows these steps:

• The hole should be drilled in the well casing on the casing side facing the direction that the well pipe will run from the well to the building it serves.
• A center punch marks the spot for the pitless adapter installation. In a freezing climate that needs to be below the frost line.

For a two-hole pitless adapter (used with 2-line jet pumps) you'll need to inscribe a vertical line down the casing and to measure the proper distance between two center punches so that the two drilled holes will be located correctly to fit the two-hole pitless adapter.

• Select a hole saw of the appropriate diameter for the pitless adapter to be installed into the well casing. Hole diameters for pitless adapters range from 1 3/4" to 3" in diameter.
  
  Naturally you'll use a hole saw with teeth and metallurgy designed for metal drilling.
  
  Use a hole saw that includes a pilot bit that centers on that punch you used as we describe above.
  
  The manufacturer of your pitless adapter will provide a table of well casing hole size diameters required for each model of pitless adapter.
• For installing the pitless adapter fitting themselves the manufacturers provide additional details on lowering the female side of the pitless adapter (attached to descending well pipes) to the proper location in the well and you may also want special wrenches provided by the manufacturer to install the external pitless adapter fittings from outside the well casing.
  
  A "pull pipe" is attached to the top of the in-casing side of the pitless adapter and is used to lower the assembly into the well.
  
  Basically the male and female parts of the new pitless adapter are installed atop the drop pipe that will be lowered into the well.
  
  For a submersible pump the pump is attached to the bottom of the drop pipe. For a 2-line jet pump the two well pipes and foot valve are attached to the pair of drop pipes.
  
  A "female" o-ring seals the face of the in-casing female adapter to the interior side of the well casing and the nose of the female adapter is pushed out through the hole you drilled in the casing.
  
  Outside the well casing a gasket, back plate and finally lock nut are installed onto the pitless adapter so that it can be connected to pipe(s) connecting the well piping to the building it serves.