For 1-inch drop pipe in 5 to 12 inch casing, choose the Boshart PA-100NL: no-lead bronze with a 2,000 lb load rating. Use the Merrill MBNL225 for 1-1/4-inch pipe or the Boshart PA-200NL for 2-inch pipe.
Top pick: Boshart PA-100NL$87.99 at AmazonPrice as of Oct 23, 2026, 5:30 AM EDT
Amazon’s photo shows a PA-125 casting; check for the PA-100NL mark when it arrives.
Pick by drop pipe size first
A pitless adapter for a well has to match three things: the drop pipe thread, the casing size and the hole cut in the casing. Every pick below was new and in stock when I re-checked Amazon on Oct 22, 2026, 6:24 PM EDT. Load figures are the makers’ own.
Amazon’s photo shows a PA-125 casting; check for the PA-100NL mark when it arrives.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.
Hole saw sizes from Boshart’s PA-NL spec sheet (2025) and Merrill’s no-lead brochure, form 2147.6 (2025), page 3.
Which pitless adapter fits your well?
For 1-inch drop pipe, 2,000 lb load
Boshart PA-100NL
Product photo: Amazon. The listing photo shows a PA-125 casting.
1 in. drop and discharge5 to 12 in. casing I.D.1-3/4 in. hole saw2,000 lb working loadO-ring AS568-3241,432 g
Buy it if
Your well has 1-inch drop pipe, casing 5 to 12 inches inside, and you want the PAS-97 listing mark.
Skip it if
Your pipe is 1-1/4 or 2 inches, or the casing wall is thicker than Boshart’s drawing allows.
The Boshart PA-100NL is where we would start for a common home setup: a submersible pump hanging on 1-inch drop pipe in a steel casing. Boshart lists it for casing with a 5 to 12 inch inside diameter, with 1-inch threads on the drop pipe side and the discharge side.
It leads on load and paperwork. Boshart rates the PA-100NL at 2,000 lb of working load, more than twice the 900 lb it gives the similar PA-800NL. Boshart also marks the PA-100NL as listed by the Water Systems Council to PAS-97, the industry standard for pitless adapters and well caps.
Boshart’s 2025 sheet adds NSF/ANSI 61 and 372, the drinking water contact and low lead standards, and pipe threads cut to ANSI/ASME B1.20.1. The elbow and slide are cast in C89833 or C89844 no-lead bronze. The O-ring and gaskets are NBR rubber, and the O-ring is a standard AS568-324 size.
The casing hole is 1-3/4 inches, the same hole saw Merrill calls for on its 1-inch MBNL models. Boshart gives the body as 2.77 by 4.47 by 2.66 inches and 1,432 grams. That body sits inside the casing, so the pump, wire and safety rope still need room to pass it.
Check the casting when it arrives: the Amazon photo shows a Boshart body marked PA-125, the 1-1/4-inch model, and the 2-inch listing uses the same photo. The listing’s part number field reads PA-100NL and its title says 1 inch. Match the casting mark and thread to your pipe before anyone cuts the casing.
Boshart’s own cheat sheet suggests an upsized drop pipe and adapter when the well sits farther from where the water needs to go. That choice belongs to whoever sized the pump and the service line. The adapter should match the pipe already in the well, or the pipe your contractor plans to use.
For 1-inch drop pipe, the PA-100NL is the one to buy. The PAS-97 listing and the 2,000 lb rating cover more wells than the 900 lb version, with the same hole size. Have a licensed well contractor confirm the casing inside diameter and wall thickness before the hole saw comes out.
Turn off the pump breaker before any well work, and leave pulling the pump or cutting the casing to a licensed well contractor. Disinfect and test the well after it has been opened.
For 1-1/4-inch drop pipe, 5 to 8 in. casing
Merrill MBNL225
Product photo: Amazon
Merrill MFG 1-1/4″ Brass Pitless Adapter MBNL225 for Submersible Well Pumps – Fits 5″-8″ Well Casings, 2-1/8″ Casing Hole, 1-1/4″ Discharge
PAS-1, PAS-97 and ASSE 1093 on Merrill’s parts sheet
150 psi and 180°F maker ratings
Replaceable O-ring with listed part numbers
Cons
Casing range stops at 8 inches
Listing calls it solid brass; Merrill says no-lead brass
1-1/4 in. drop and discharge5 to 8 in. casing2-1/8 in. hole saw300 ft water-filled schedule 40 steel, plus pumpO-ring OR3263.8 lb
Buy it if
Your system runs 1-1/4-inch pipe in 5 to 8 inch casing and you want every spare part number on file.
Skip it if
Your casing is over 8 inches, or your pipe is 1 or 2 inches.
The Merrill MBNL225 is the pick for 1-1/4-inch drop pipe. Merrill’s 2025 no-lead brochure lists it for 5 to 8 inch casing, with a 2-1/8-inch casing hole and 1-1/4-inch threads. It was new and in stock when I re-checked Amazon on Oct 22, 2026.
Merrill rates load differently from Boshart. Its brochure says the MBNL225 will support 300 feet of schedule 40 steel pipe full of water, plus the pump. Boshart rates in pounds of working load. Neither maker converts one figure into the other, so we don’t rank them against each other.
Merrill’s stainless SSMBI100 shows why the basis matters: Merrill rates that model by length of 160 psi poly pipe, not steel. Pipe material, pipe size, the pump and the water inside all add to what hangs on the adapter. Size a deep well from the maker’s table for the exact pipe in the hole.
The MBNL225 parts sheet lists PAS-1, PAS-97 and ASSE 1093 certification, with a 150 psi maximum pressure and 180°F maximum temperature. Merrill notes an extra thick wall on the discharge through the casing to help carry the weight. Its brochure says the O-ring can be replaced in the field, not only at the factory.
Replacement parts have their own numbers: male half MBMNL22, female half MBFNL22, O-ring OR326 and female seal MBFR12. Write those down with the model and the install date. A leak at the seal years later can then be fixed with the right part, not guessed from a photo of a buried fitting.
Merrill’s brochure marks the MBNL225 with its CA Certified symbol. Its California warning covers only models marked with the plain No-Lead symbol, such as the MBNL250. The Amazon listing calls the body solid brass; Merrill calls it no-lead brass.
Choose the MBNL225 when the system already runs 1-1/4-inch pipe and the casing is 5 to 8 inches. Casing larger than 8 inches is outside Merrill’s listed range for this model, so stop and have your contractor pick a model rated for that size.
For 2-inch drop pipe, 5,000 lb load
Boshart PA-200NL
Product photo: Amazon. The listing photo shows a PA-125 casting.
Needs a 3-1/8-inch hole and a crew to lift the column
2 in. drop and discharge5-5/8 to 12 in. casing I.D.3-1/8 in. hole saw5,000 lb working loadO-ring AS568-3326,380 g
Buy it if
Your pump and service line already use 2-inch pipe and the casing is at least 5-5/8 inches inside.
Skip it if
Your house runs 1-inch or 1-1/4-inch pipe; the hole and threads will not match.
The Boshart PA-200NL handles 2-inch drop pipe, the top of the slide-type range. Boshart’s cheat sheet says slide adapters cover homes and commercial wells up to 2-inch pipe, and spool types take over beyond that. This one fits casing with a 5-5/8 to 12 inch inside diameter and needs a 3-1/8-inch hole.
Its 5,000 lb working load is the highest Boshart lists among its no-lead bronze slide models. Use it when the pump and service line are already designed around 2-inch pipe. It is the wrong part for a house on 1-inch pipe, because the hole is larger and the threads will not match.
Boshart gives the body as 4.75 by 6.76 by 4.55 inches and 6,380 grams, a little over 14 pounds. That is a lot of bronze to line up inside a 6-inch casing. The O-ring is AS568-332, Boshart part 09-PA-200-OR-332, and the model carries the same PAS-97 listing mark as the PA-100NL.
Merrill’s bronze 2-inch model, the MBNL300, calls for a 3-inch hole, while Boshart calls for 3-1/8 inches. Hole sizes differ by brand even at the same pipe size. Use the hole saw named on the sheet for the exact adapter you have, because a hole cut for one brand may not seal the other.
The Amazon photo here is the same image used on the 1-inch listing: a casting marked PA-125. The part number field reads PA-200NL and the title says 2 inch. A 2-inch adapter is far larger than a 1-1/4-inch one, so the size should be plain on arrival. Don’t install it unless the casting matches.
A 2-inch column full of water, plus a larger pump, is heavy. Lifting it needs a hoist or pump puller and a crew that does this work. The adapter is rated for the load; the people lifting it are not. This is a job for a licensed well contractor from start to finish.
Buy the PA-200NL only to match existing or planned 2-inch drop pipe in casing at least 5-5/8 inches inside. For smaller pipe, the PA-100NL or MBNL225 fits better and needs a smaller hole in the casing.
For 1-inch drop pipe, 900 lb load
Boshart PA-800NL
Product photo: Amazon
1″ Bronze Pitless Adapter, Lead Free (900 lbs Load)
1 in. drop and discharge5 to 12 in. casing I.D.1-3/4 in. hole saw900 lb working loadO-ring AS568-3241,334 g
Buy it if
You have a lighter 1-inch setup and your local code does not require a PAS-97 listed adapter.
Skip it if
Your inspector requires a listed adapter, or the column weight is anywhere near 900 lb.
The Boshart PA-800NL is the second 1-inch choice. It shares the PA-100NL’s 1-inch threads, 5 to 12 inch casing range, 1-3/4-inch hole and AS568-324 O-ring. The difference sits in Boshart’s own table: 900 lb of working load instead of 2,000, and no PAS-97 listing mark next to the model.
That missing mark matters where a listed adapter is required. The Water Systems Council keeps a public list of makers with products tested to ASSE 1093/PAS-97, the standard for pitless adapters, pitless units and well caps; Boshart, Merrill and Campbell are on it. Check your state or county well code before choosing an unlisted adapter, because the inspector’s rule outranks any product page.
Its listing photo is the one that matches: the casting in the image reads PA-800NL. Boshart gives the body as 2.84 by 4.35 by 2.72 inches and 1,334 grams, close to the PA-100NL. Size alone will not tell the two apart, so keep the box and the casting mark with your well records.
What does 900 lb mean in practice? Boshart does not convert it to feet of pipe, and we won’t either. The load includes the drop pipe, the water inside it, the pump, the motor and the wire. A shallow well with a small pump may sit well under it; a deep steel column may not.
Boshart publishes the largest casing wall thickness for each model as drawings, measured with the gaskets and nut fully engaged. Thick-wall or older casing can exceed it. Have the contractor measure the wall at the cut and compare it with Boshart’s drawing for this exact model before cutting.
The materials match the rest of the PA-NL line: no-lead bronze elbow and slide, NBR rubber O-ring and gaskets. Boshart’s 2025 sheet lists the washer and nut as C83600 bronze, where its 2020 sheet said no-lead bronze. Both parts sit outside the casing, but ask Boshart if your inspector needs that answered in writing.
Treat the PA-800NL as the backup for a lighter 1-inch setup where the local code does not require a PAS-97 listed adapter. If you are unsure on either point, choose the PA-100NL, which uses the same hole and the same O-ring.
Compare the four picks side by side
Sort by drop pipe or hole saw size on a wide screen. Load figures use each maker’s own basis, so a Merrill length and a Boshart weight are not the same kind of number.
Same hole and O-ring as PA-100NL No PAS-97 mark; lowest rating
All four offers were new and in stock when I re-checked the Creators API on Oct 22, 2026, 6:24 PM EDT. Sellers on these listings change, so recheck the exact model and the casting mark at checkout.
How does a pitless adapter work?
Simplified diagram based on Merrill’s and Boshart’s install guides. Not to scale and not a product photo.
A well pitless adapter connects the submersible pump’s drop pipe to the buried water line that runs to the house. It does this below the frost line, through a hole in the side of the well casing. The casing can then stand above ground with a sealed cap, instead of ending in an old-style pit.
It comes in two halves. One half bolts through the casing wall and stays put; the service line threads onto its outside. The other half threads onto the top of the drop pipe and slides into the fixed half from above. An O-ring seals the joint, and the weight of the pipe holds it down.
Boshart’s cheat sheet sums it up: everything in the well hangs off the pitless adapter. The drop pipe, the water inside it, the pump and the motor all rest on that one sliding joint. That is why the load rating matters and why the casing hole has to be cut cleanly.
To service the pump, a contractor threads a length of pipe into the top of the drop-pipe half, lifts it out of the seat and pulls the pump straight up. Merrill says an adapter in casing 5 inches or larger lets the pump and pipe come out without digging up the fixed half.
Part
Merrill name
Boshart name
What it does
Fixed half
Female part
Slide (part E)
Bolts through the casing wall and feeds the service line
Moving half
Male part
Elbow (part F)
Threads onto the drop pipe and lifts out with the pump
Joint seal
O-ring
O-ring
Seals the two halves inside the casing
Outside seal
Molded gasket and collar
Outer gasket (C)
Seals the casing hole on the outside
Inside seal
Glued gasket or O-ring
Inner gasket (D)
Seals the casing hole on the inside
Clamp
Lock nut and backplate
Washer (B) and compression nut (A)
Pulls the gaskets tight against the casing
The names change by brand, but the layout does not. Merrill’s install guide uses male and female parts. Boshart’s instructions letter the parts A to F. The drawing labels both, so either maker’s parts list will match it.
Types of pitless adapters
Slide-type adapters are the most common design for home well pump systems with a submersible pump. The other types solve narrower problems.
Type
Where it fits
Maker example
Slide type
Homes and commercial wells, up to 2-inch drop pipe
Boshart PA-NL, Merrill MBNL
Spool type
Commercial wells and larger pipe
Named in Boshart’s cheat sheet
Double drop
Jet pumps, which need a send and a return line
Boshart PA-2XNL
Pressurized
Offered as an option in Boshart’s no-lead bronze line; ask the maker or your inspector where one is required
Boshart (cheat sheet)
Illinois code
Wells in Illinois, which keeps its own approved list
Merrill MBPNL and SSMBP models
Concrete tile
Wells lined with concrete tile, not steel
Merrill N models
Pitless unit
A factory-made casing section, welded or clamped on
Covered by Minnesota rule 4725.4850
A slide-type pitless adapter for a well pump is the part most people mean. Boshart says it is the most common type. It also lists the slide type for shallow-well jet pumps with a foot valve, limited to a 25-foot-deep well, or 30 feet in ideal conditions at sea level.
A double-drop adapter carries two pipes because a deep-well jet pump sends water down and brings it back up. Boshart’s PA-2XNL takes 1-inch and 1-1/4-inch pipe and needs two holes, 1-3/4 and 2-1/8 inches. A jet pump pitless adapter is not interchangeable with a single-pipe model.
A pitless unit replaces the top of the casing with a factory section rather than adding a fitting through the wall. Minnesota’s code says the installer of a weld-on or clamp-on pitless adapter must use a guide or template to cut the casing hole. Compression-seal units need the casing to reach at least 2.5 inches into the unit’s throat.
Flowing wells, where water rises above ground on its own, are a separate case. Illinois’s approved list names pitless units with flowing well modifications. A flowing well pitless adapter is a contractor-and-inspector decision, and we don’t pick one here.
Pitless adapter sizing chart from the maker sheets
Figures from Boshart’s and Merrill’s 2025 documents. Rows without a buy link are here for sizing only.
Model
Material
Drop pipe, in.
Casing, in.
Hole saw, in.
Maker load basis
Listed
Boshart PA-100NL
No-lead bronze
1
5 to 12 I.D.
1-3/4
2,000 lb
PAS-97
Boshart PA-800NL
No-lead bronze
1
5 to 12 I.D.
1-3/4
900 lb
No mark
Boshart PA-125NL
No-lead bronze
1-1/4
5 to 12 I.D.
2-1/8
2,000 lb
PAS-97
Boshart PA-200NL
No-lead bronze
2
5-5/8 to 12 I.D.
3-1/8
5,000 lb
PAS-97
Boshart PA-2XNL
No-lead bronze, double drop
1 and 1-1/4
4-1/2 to 12 I.D.
1-3/4 and 2-1/8
2,000 lb
PAS-97
Merrill MBNL50
No-lead brass
1
5 to 8
1-3/4
300 ft*
Line
Merrill MBNL200
No-lead brass
1
5 to 8
1-3/4
400 ft*
Line
Merrill MBNL225
No-lead brass
1-1/4
5 to 8
2-1/8
300 ft*
Line
Merrill MBNL250
No-lead bronze
1-1/2
6 to 12
2-3/8
600 ft*
Line
Merrill MBNL300
No-lead bronze
2
6 to 12
3
600 ft*
Line
Merrill SSMB50
Stainless steel
1
5 to 8
1-3/4
600 ft*
Line
Merrill SSMB225
Stainless steel
1-1/4
5 to 8
2-1/8
800 ft*
Line
* Merrill rates support as a length of schedule 40 steel pipe full of water, plus the pump. Boshart rates working load in pounds. “Line” means Merrill’s brochure lists PAS-1, PAS-97 and ASSE 1093 for its pitless adapter line rather than model by model.
Read the chart from left to right. First find the drop pipe size already in the well. Then check that the casing falls inside the range, then note the hole saw. If the casing is 4 inches, none of these models lists it; ask a contractor which design is rated for that casing.
The 4-1/2 inch start on the PA-2XNL is the smallest casing in either maker’s table. Boshart’s spec bullets say the line fits 4-1/2 to 12 inch casing, but its rows start the single-drop models at 5 inches. We use the row figure for each model.
Two numbers need care. Merrill’s brochure gives the MBNL250 a 2-3/8-inch hole, while its install guide lists 2-1/2 inches. We show the brochure figure and flag both. Ask Merrill before cutting if you are fitting that model.
Cutting the casing hole
This is the step that cannot be undone. It is work for a licensed well contractor, and the notes below are for checking the job, not doing it.
Both makers start the same way. The hole goes below the local frost depth, lined up with the trench for the service line. Merrill’s guide says to center punch the casing and cut with the hole saw for the exact model. Boshart says to remove the burrs from the cut, which lets the gaskets seat flat.
Boshart says not to use a cutting torch. A torch leaves a rough, oversized hole and heats the casing; a hole saw leaves a clean round edge the gaskets can seal against. If an old torch-cut hole is already there, ask the contractor whether a new adapter can seal it at all.
1
Measure the casing
Confirm the inside diameter and wall thickness. Compare both with the sheet for the exact adapter, not a family range.
2
Find the frost-safe depth
Use the local code depth and line the hole up with the service line trench. Don’t guess from another state’s rule.
3
Cut with the named hole saw
Center punch, cut with the hole saw size the maker lists and deburr. No cutting torch, per Boshart.
4
Fit and tighten the casing half
Seat the gaskets, then tighten the nut until the gaskets visibly compress, per Boshart. Merrill says not to remove the female O-ring.
5
Lower the pump half with a pipe
Thread a pull pipe into the top, keep it upright and seat the elbow firmly. Boshart uses a removable safety pin while setting it.
Wall thickness limits the fit. Boshart publishes the largest casing wall each model can take, with the gaskets and nut fully engaged. Older steel casing can be thicker than modern pipe. A contractor can measure it at the hole and compare it with the drawing before cutting.
Minnesota’s rule says the adapter must leave complete clearance inside the casing. That keeps the pump, wire and safety rope free to pass. A large adapter in a small casing can block a later pump pull, which is another reason the casing inside diameter should be measured, not guessed.
Boshart’s instructions use a safety pin, such as a wooden dowel or plastic pipe sticking out at least 1/4 inch, to hold the parts while they are set. Merrill’s brochure shows a built-in installation tool on its adapters. Either way, the drop pipe is lowered on a threaded pull pipe, never by hand on the wire.
What the load rating covers
Every pound in the well hangs on the adapter. The rating is the load each maker says its adapter can carry, in pounds or in feet of water-filled pipe.
The load is the full column: the drop pipe, the water inside it, the pump, the motor, the wire and any torque arrestor or safety rope. A full column of water adds a great deal to the weight of the pipe alone, and the deeper the pump, the more water the pipe holds.
Length of schedule 40 steel pipe full of water, plus pump
MBNL225 300 ft; MBNL300 600 ft
Merrill stainless
Same steel pipe basis
SSMB50 600 ft; SSMB225 800 ft
Merrill SSMBI100
Length of 160 psi poly pipe full of water, plus pump
Poly basis, not steel
Boshart gives a number of pounds. Merrill gives a length of schedule 40 steel pipe full of water, plus the pump, and says its stainless SSMBI100 is rated by 160 psi poly pipe instead. Those are different measuring sticks. We list each in the maker’s own terms and do not convert them.
Use the rating to rule an adapter out, not to prove it is safe. If the column is close to a rating, step up to a heavier model and have the contractor confirm the numbers for the actual pipe and pump. Read our submersible well pump guide for the pump side of that choice.
Pulling that column is the dangerous part. A steel column full of water can weigh more than one person should lift, and a slip drops the pump to the bottom of the well. Contractors use a hoist or pump puller for this reason.
No-lead bronze, brass and stainless
The picks here are all no-lead bronze or brass. The certifications matter more than the metal name.
Material
Example
What the maker lists
No-lead bronze
Boshart PA-100NL, PA-200NL
NSF/ANSI 61 and 372; C89833 or C89844 bronze body
No-lead brass
Merrill MBNL225
PAS-1, PAS-97, ASSE 1093; 150 psi, 180°F
Stainless steel
Merrill SSMB series
Higher support lengths in Merrill’s table
O-ring and gaskets
Both brands
NBR rubber on Boshart; replaceable O-ring on Merrill
NSF/ANSI 372 covers lead content in drinking water parts, and NSF/ANSI 61 covers what a part can add to the water. PAS-97, also published as ASSE 1093, covers pitless adapters, pitless units and well caps. A part can carry one without the other, so read the sheet for the exact model.
Merrill’s brochure marks each model either CA Certified or No-Lead only. The No-Lead-only models, such as the MBNL250, carry a warning that they haven’t been specifically tested or approved as no-lead in California. Boshart’s V2 sheet lists the outside washer and nut as C83600 bronze; ask your inspector if that matters locally.
Minnesota’s code puts the plain version of the rule into law: the adapter must not add taste, odor or toxic material to the water. A no-lead mark, a listing and an inspector’s approval are three separate checks. A well with old leaded fittings elsewhere still needs a water test to know what is in the tap.
How deep does a pitless adapter go?
There is no single national depth. The local frost depth and well code set it.
The adapter sits below the frost line so the water line never freezes where it leaves the casing. Boshart says to line the hole up with the trench at a frost-safe bury depth. Your county or state code sets that depth, and a contractor in your area will know it.
The casing still has to rise above ground. Minnesota’s rule requires the casing to extend at least 12 inches above grade. That is the point of a pitless adapter: it moves the connection underground while the well top stays sealed and in the open.
Minnesota rule
What it requires
Casing height
At least 12 inches above grade
Connection below 12 inches
Pitless adapter or pitless unit, not underwater when installed
Backfill
Native material packed tightly around the adapter
Inside the casing
Complete clearance within the casing inside diameter
Pump wiring
Enters at least 12 inches above grade
Minnesota also says any casing connection less than 12 inches above grade must use a pitless adapter or pitless unit, must not be underwater when installed, and needs native soil packed tightly around it. It also requires pump wiring to enter the casing, cap or pump base at least 12 inches above grade.
Those rules are one state’s example, not a national code. Check your own state or county before any work. A sanitary seal at the casing hole and a tight well cap keep surface water and insects out of the drinking water, so a leaking adapter is a water quality problem as well as a pressure problem.
Pulling a pump through a pitless adapter
Knowing how a pump is pulled helps you hire well and spot a careless job. The work itself belongs to a licensed well contractor.
Never work on a live pump circuit
Shut the pump breaker off, use a lockout hasp if the panel has one, and confirm power is off with a voltmeter, as Minnesota’s health department directs before disinfecting a well. Water and electricity together can kill.
Do not lift the column by hand
The drop pipe, water, pump and wire can be far heavier than they look. A licensed well contractor uses a hoist or puller and a threaded pipe in the adapter top, never the pump wire.
Never torch the casing
Boshart says not to use a cutting torch on the casing hole. A licensed well contractor should cut the casing with the hole saw the maker names.
Keep the well covered
An open casing lets dirt, insects and surface water in. Keep it capped between steps and plan to disinfect the well once the work is done.
Check the seal after the job
Look for wet soil or a sinking spot over the line near the well. A leaking O-ring or gasket can let surface water reach the drinking water.
Keep the records
Write down the adapter model, O-ring number, hole size, pump depth and install date. The next pump pull starts with the right parts.
Boshart notes its adapters are designed to make raising a submersible pump for service or replacement easier. A contractor threads a pull pipe into the top of the drop-pipe half, lifts it out of the fixed half, and then raises the pump and pipe up through the casing. The service line stays buried.
If the pump is coming out because pressure is poor, check the rest of the system as well. A failing pressure switch or a waterlogged pressure tank can look like a pump problem. A pump pull is a big job to do for a part on the surface.
Disinfect and test the well afterward
Florida’s health department says a well can pick up harmful bacteria while it is open for repair, and lists well or pump repairs as a reason to disinfect. Minnesota’s method shows what a careful job looks like.
The Minnesota Department of Health says you can hire a licensed well contractor to disinfect a well. Its method turns the pump breaker off, uses a lockout hasp if the panel has one, and checks with a voltmeter. Wear goggles or a face shield and rubber gloves when handling bleach.
Step
What the Minnesota method says
Power
Pump breaker off, lockout hasp if present, voltmeter check
Protection
Goggles or face shield and rubber gloves
Chlorine
50 to 200 ppm, never above 200
Contact time
At least 2 hours, preferably 6 hours or overnight
Testing
Total coliform at an accredited lab, retest in 2 to 4 weeks
It calls for unscented household bleach with 6 or 8.25 percent sodium hypochlorite and no additives, never pool or hot tub chemicals. The target is 50 to 200 parts per million of chlorine, never above 200. The solution sits for at least two hours, preferably six hours or overnight.
Flush the chlorinated water away from the septic system, landscaping and any water bodies. After the chlorine is gone, the health department recommends a total coliform test at an accredited lab before drinking the water, and a retest two to four weeks later because coliform can regrow.
One step protects the adapter itself. Wisconsin’s natural resources department warns that bleach poured straight into the well can land on the pitless adapter and corrode through it if not rinsed. Its fix is to pre-mix the solution at the surface or pour it through a drop tube past the adapter.
Ask the contractor how they will disinfect the well after the adapter or pump work, and who will take the water sample. A home water test kit can screen for problems, but a certified lab result is the one to trust for bacteria.
Where listings and maker sheets disagree
Where a listing and the maker disagree, we use the maker’s figure.
Item
Listing or one document says
Maker sheet says
What we did
Boshart 1-inch and 2-inch photos
Both listings show the same casting, marked PA-125
Part numbers read PA-100NL and PA-200NL
Kept both picks; check the casting on arrival
Boshart casing range
Spec bullet: fits 4-1/2 to 12 in. I.D.
Rows: 5 to 12 in. for PA-100NL and PA-800NL
Used the row figure
Merrill MBNL250 hole saw
Install guide: 2-1/2 in.
Brochure: 2-3/8 in.
Showed the brochure figure; ask Merrill
Boshart washer and nut
2020 sheet: no-lead bronze
2025 sheet: C83600 bronze
Flagged for the inspector
Merrill MBNL225 body
Listing: solid brass
Brochure: no-lead brass
Used the maker term
The Boshart photo problem is the one most likely to cause a wrong part. The casting in the shared image reads PA-125, which is neither the 1-inch nor the 2-inch model. The part number field and title on each listing still point to the right model, so we kept them and put the check in each card.
Adapters we left off the list
The Water Source PA100NL was New and in stock, but we could not find a maker spec sheet for it, and the product data names Standard Plumbing Supply as the manufacturer. Without a maker sheet for the casing range, hole size and load, we could not size it against the others.
The Campbell 1-inch listing was in stock, but its brand field was blank in our read and the image was a silhouette drawing, not a photo. The product data names Campbell Manufacturing and part B-10XLF. We left it off until the brand and model can be confirmed from the maker.
The Merrill MBNL50 and stainless SSMB50 showed only one or two units in our October 20 read. They appear in the sizing chart because their maker figures are useful, but we don’t pick them while stock is that thin.
We also found no branded pitless adapter tool for setting or pulling on Amazon in our October 20 search; contractors use a threaded pull pipe.
Choose a pitless adapter in five checks
1
Read the drop pipe size
Many homes run 1-inch or 1-1/4-inch pipe. Match the adapter thread to the pipe already in the well or the pipe your contractor plans.
2
Measure the casing
Check the inside diameter and wall. Merrill’s brass models stop at 8 inches; Boshart’s slide models run to 12.
3
Note the hole saw
Each model names one. A hole cut for another brand may not seal.
4
Check the load and the listing
Compare the column weight with the maker’s rating, and check whether your code needs a PAS-97 listed adapter.
5
Plan the safe job
Breaker off and locked, a licensed well contractor for the pull and the cut, then disinfection and a lab test.
Sign
What it can mean
Next step
Wet ground near the well
A leaking seal or line
Call a licensed well contractor
Corrosion on the adapter
Old metal near the end of its life
Plan a replacement with the pump pull
Adapter will not lift out
Stuck O-ring or wrong part
Leave it to the contractor
Wrong pipe size for the pump
Earlier mismatch
Size the new adapter to the planned pipe
Merrill’s guide lists the usual reasons to replace a pitless adapter: it leaks, it is corroded, it is hard to service, it is damaged, or it is the wrong size. Most of those are found during a pump pull, so it makes sense to have the right adapter on hand before the crew arrives.
Questions about pitless adapters
What is the best pitless adapter for a well?
For 1-inch drop pipe in 5 to 12 inch casing, the Boshart PA-100NL is our pick: no-lead bronze, a 2,000 lb working load and the PAS-97 listing mark. Use the Merrill MBNL225 for 1-1/4-inch pipe in 5 to 8 inch casing, or the Boshart PA-200NL for 2-inch pipe.
What does a pitless adapter do?
It connects the drop pipe from a submersible pump to the buried water line through the side of the casing, below the frost line. It keeps the casing sealed above ground and lets a contractor lift the pump out from the top without digging up the yard line.
How does a pitless adapter work?
One half is clamped through the casing wall and feeds the service line. The other half threads onto the drop pipe and slides down into it, sealed by an O-ring. The weight of the pipe and pump holds the joint closed. A pipe threaded into the top lifts it out.
How far down is a pitless adapter?
It goes below the local frost depth, lined up with the water line trench. That depth changes by region and is set by the local code. The casing itself still has to rise above grade; Minnesota, for example, requires at least 12 inches.
How do you pull a well pump with a pitless adapter?
A licensed well contractor turns the pump breaker off, threads a pull pipe into the top of the drop-pipe half, lifts it out of its seat and raises the pump and pipe up the casing with a hoist or puller. The well is then disinfected and tested.
Is a pitless adapter necessary?
Where a connection is made to a casing less than 12 inches above grade, codes such as Minnesota’s require a pitless adapter or pitless unit. That same code requires the casing to rise at least 12 inches above grade. Check your own state or county well rules.
What are the types of pitless adapters?
Slide types are the most common for homes and run up to 2-inch drop pipe. Spool types serve larger commercial pipe, and double-drop models serve jet pumps. Boshart also offers a pressurized option, and Merrill sells Illinois-code models. Pitless units, which replace a section of casing, are a separate product class.
What size hole does a pitless adapter need?
It depends on the model. Boshart and Merrill both call for 1-3/4 inches on the 1-inch slide models in our chart and 2-1/8 inches on the 1-1/4-inch ones. Merrill’s stainless SSMBI100 needs only 1-3/8 inches. For 2-inch pipe, Boshart’s PA-200NL needs 3-1/8 inches and Merrill’s MBNL300 needs 3 inches.
Is there a pitless adapter for 4 inch casing?
None of the slide models in our chart lists 4-inch casing. Boshart’s double-drop PA-2XNL starts at 4-1/2 inches inside diameter, and the rest start at 5 inches or more. Have a contractor confirm a design rated for small casing before any cutting.
Can I install a pitless adapter myself?
The job means cutting the casing, lifting a heavy column and working near pump wiring, then disinfecting the well, so we recommend a licensed well contractor. Some states require a license for parts of this work. Wisconsin, for example, requires a licensed pump installer to disinfect the well after regulated pump work. Check your local rules first.
How we pick and why trust us
Why trust us
Isaac Daniels, a licensed journeyman plumber in Georgia, owns PlumbingPicks and is responsible for this page. We read Boshart’s and Merrill’s spec sheets, install guides and brochures, plus Minnesota’s well code and the Minnesota, Florida and Wisconsin disinfection guidance. No install stories or test results are claimed.
How we pick
We matched each adapter to a drop pipe size, then compared casing range, hole saw size, maker load rating and listing marks. A Creators API re-check on Oct 22, 2026, 6:24 PM EDT confirmed each pick was new and in stock, and the photos come from the same API.
Where a listing and a maker sheet disagree, we use the maker’s figure and show the conflict. Load ratings stay in each maker’s own terms. Each card carries our spec score, worked out check by check below: four checks, equal weight. No customer ratings or typed prices are used.
The spec score, check by check
Each check scores 0 to 10 and counts one quarter. It rewards a PAS-97 listing, a wide casing range, spare part numbers you can order later and an Amazon listing that matches the maker. It’s our score from the makers’ sheets, not a customer rating or a leak test.
Load ratings stay out of the score. Boshart rates in pounds and Merrill in feet of water-filled steel pipe, so the two can’t be lined up fairly. Pick the load from the maker’s own table for your pipe and pump. The PA-800NL scores lowest because Boshart’s table shows no PAS-97 mark for it.
Check (weight)
How it’s scored
Watertight listing (¼)
10 when the maker’s sheet marks the model as listed to PAS-97 / ASSE 1093; 0 when it doesn’t
Casing range (¼)
Span of casing inside diameters the maker lists: 10 for 6 in. or more; 8.5 for 4 to 6 in.; 7 under 4 in.
Spare parts (¼)
10 when the maker gives part numbers for the O-ring, seal and both halves; 8.5 for the O-ring only
Listing match (¼)
10 when the Amazon photo and title match the maker’s model; 8.5 when a word conflicts with the maker; 7 when the photo shows another model
Total
Average of the checks, to one decimal
Pick
Watertight listing
Casing range
Spare parts
Listing match
Score
Boshart PA-100NL
10
10
8.5
7
8.9
Merrill MBNL225
10
7
10
8.5
8.9
Boshart PA-200NL
10
10
8.5
7
8.9
Boshart PA-800NL
0
10
8.5
10
7.1
Check
Method
Limit
Fit
Drop pipe thread, casing range and hole saw from maker sheets
Wall thickness still needs a measurement
Load
Maker’s own rating basis
Pounds and feet of pipe are not converted
Listing
PAS-97 mark and NSF/ANSI listings on maker sheets
Local code decides what is required
Offer
New, in stock, genuine brand and model on October 22
Stock changes; recheck at checkout
Spec score
Four checks from the maker sheets and the listing, equal weight
Load ratings aren’t scored; the makers state them on different bases
Boshart, PA-NL spec sheet (2024 issue) and PA-NL sheet (2020): earlier sizing and washer and nut material. https://images.boshart.com/boshartimages/2024/10/PA-NL-81P100-BII-1.pdf and https://images.boshart.com/boshartimages/2022/04/PA-NL_No-Lead-Bronze-Pitless-Adapter.pdf
Boshart, Pitless Adapter Cheat Sheet: types, frost line role, pipe size advice, double drop for jet pumps. https://accelerator.boshart.com/wp-content/uploads/2024/05/Pitless-Adapter-Cheat-Sheet.pdf
Boshart support, How do I properly install my pitless adapter: parts A to F, frost-safe depth, no cutting torch, safety pin, pull pipe. https://support.boshart.com/how-do-i-properly-install-my-pitless-adapter
Boshart support, Maximum well casing wall thickness for a pitless adapter: per-model drawings. https://support.boshart.com/what-is-the-maximum-well-casing-wall-thickness-a-pitless-adapter-can-be-installed
Merrill, No-Lead Pitless Adapters brochure, form 2147.6 (2025), pages 2 to 4: models, casing, hole saws, support lengths, certifications, California note. https://merrillmfg.com/cdn/shop/files/No_Lead_Pitless_Adapters_BrochureDigital_v1_052025.pdf
Merrill, MBNL pitless adapter parts spec sheet (04/2025): replacement part numbers, PAS-1, PAS-97, ASSE 1093, 150 psi and 180°F. https://merrillmfg.com/cdn/shop/files/MBNL_SpecSheet_v1_042025_PitlessAdaptersParts.pdf
Merrill, MBNL bronze spec sheet (04/2025): bronze model certifications and ratings. https://merrillmfg.com/cdn/shop/files/MBNL_SpecSheet_v1_042025_Bronze.pdf
Merrill, Pitless adapters guide: what the adapter does, 5-inch casing note, reasons to replace. https://merrillmfg.com/pages/pitless-adapters-guide-1
Minnesota Rules 4725.4850 (pitless adapters and units), 4725.3150 (wire entry) and 4725.2250 (casing height). https://www.revisor.mn.gov/rules/4725.4850/
Minnesota Department of Health, Well Disinfection: power lockout, PPE, bleach strength, contact time, flushing and coliform testing. https://www.health.state.mn.us/communities/environment/water/wells/waterquality/disinfection.html
Illinois Department of Public Health, approved pitless adapters list (2009). https://idph.illinois.gov/envhealth/pdf/WW_Pitless_Adapters.pdf
Water Systems Council, PAS-97 listing of products meeting the standard: Boshart, Merrill, Campbell and others, read October 21, 2026. https://www.watersystemscouncil.org/pas-97-listing-of-products-meeting-the-standard/
ASSE International and Water Systems Council, ASSE 1093-2019 / WSC PAS-97 (2019) release: covers pitless adapters, pitless units and well caps; sanitary connection role. https://iapmo.org/media/eiahw0gq/2020-03-16-asse-1093-wsc-pas-97-now-available.pdf
Florida Department of Health, Well water facts: disinfection; contamination while the well is open for repair; disinfect after well or pump repairs. https://www.floridahealth.gov/wp-content/uploads/2026/06/well-water-facts-disinfection.pdf
Wisconsin DNR, DG-118 well disinfection fact sheet: licensed pump installer disinfects after regulated pump work; protect the pitless adapter from concentrated bleach. https://dnr.wisconsin.gov/sites/default/files/topic/DrinkingWater/Publications/DG118.pdf
Amazon Creators API: offers re-read Oct 22, 2026, 6:24 PM EDT (B08BZTP5CH, B09T8BV2HH, B08BLQJK14, B08BZTS4M1, all new and in stock); first reads October 20 to 21, 2026; images read October 20, 2026; part numbers and UPCs for the Boshart listings read October 20 to 21, 2026.
CPSC recall search (saferproducts.gov API), re-run Oct 22, 2026 for pitless adapter, Boshart and Merrill: no recall.
