Pitless Unit
Best for New Installations
A complete, heavy-duty system designed for new well installations and easier future pump service.
Choose Pitless UnitPay More Now. Fewer Headaches Later.
Find the Right Pitless UnitA complete, factory-tested pitless system built for dependable installation, easier well access, and simpler future service.
- Factory Pressure Tested
- Full-Diameter Well Access
- Built for the Long Haul
- Multiple Sizes and Lengths Available
For new wells and long-term installations.
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Why Does the Merrill Pitless Unit Cost More?
Because it is more than a basic pitless connection.
- Water Flow Parts
- Casing Included
- Holds More Weight
- Easier Future Service
Pitless Unit, Kit, or Adapter?
Choose the option that best matches your installation, replacement needs, and existing well setup.
Pitless Kit
Best for Complete Replacement
A bundled option for installations that need the adapter and supporting internal components together.
Choose Kit
Pitless Adapter
Best for Replacing an Adapter
A practical choice when economy is important compatible with many casing sizes 5" or larger.
Choose AdapterHow to Select Your Pitless Unit In 3 Simple Steps
Step
1
What Is Your Casing Size?
Select the pitless unit that matches the inside diameter of your well casing.
Step
2
What Is Your Bury Depth?
Measure from finished grade to the centerline of the service-line connection.
Step
3
What Are Your Drop-Pipe and Discharge Sizes?
Match the pitless unit to the sizes of your drop pipe and underground service line.
Compare Pitless Units
Which Merrill Pitless Unit Is Right for You?
Four proven options. The same dependable Merrill quality.
SP
Time Proven
The proven, field-favorite design for most well installations.
Shop SPSPP
Illinois Code Approved
The proven SP-style design configured to meet Illinois code requirements.
Shop SPPSSMCU
Clear Access for Well Chlorination
The removable internal assembly leaves the well casing unobstructed, making chlorination and future service easier.
Shop SSMCUH2O
Pitless Control Unit
An integrated control solution designed for expansion-tank and variable-frequency-drive mounting. Inside the well.
Shop H2OInstallation Overview
SP Pitless Unit Cross Section
See how the Merrill SP Pitless Unit creates a secure underground water connection while allowing the internal assembly to be serviced from the top of the well.
What Comes With a Merrill SP Pitless Unit?
Each component is designed to work together as one complete system for installation, support, sealing, discharge, and future well-pump service.
Factory-Assembled Upper Casing
The complete outer casing supports the pitless-unit assembly and creates the foundation for the underground connection.
Internal Complete Assembly
The removable internal assembly supports the drop pipe and allows the well pump to be accessed from the top.
Sealing or Adjustment Hardware
Moves the seals into the discharge to secure the internal assembly and complete the discharge connection.
Top Support Plate
The upper support plate secures the internal assembly and helps support the connected drop-pipe system and pump.
Well Cap (When Selected)
Select configurations can include a well cap to cover and protect the top of the completed well installation.
Pitless Unit FAQs
Common Questions
What’s the Difference Between a Pitless Unit, Pitless Kit and Pitless Adapter?
- Pitless unit: Complete, heavy-duty option for a new well.
- Pitless kit: Used to convert or complete an existing well casing.
- Pitless adapter: Lower-cost option that requires more separate components.
How Do I Choose the Right Pitless Unit?
Match the pitless unit to your well-casing diameter, bury depth, discharge size and drop-pipe size. Check local well codes before ordering.
What Bury Depth Do I Need?
The discharge must be installed below your local frost line. Bury-depth requirements vary by location, so check local well codes.
Will a Pitless Unit Fit My Existing Well Casing?
It may, depending on the casing diameter, material and condition. Confirm your casing specifications before ordering.
Can I Install a Pitless Unit Myself?
Usually, this is a job for a well driller or pump installer. Installation requires excavation, casing work, proper sealing and code compliance.
What Comes With a Merrill SP Pitless Unit?
It includes the unit casing, discharge outlet, internal sealing assembly, pull pipe, support plate, screened vent and cap.
Can a Well Pump Be Serviced Without Digging?
Yes. The pump and internal assembly can be pulled through the top of the well while the buried water line stays in place.
Is a Pitless Unit Worth the Extra Cost?
For a new well, often yes. You get a complete, heavy-duty system with easier access for future pump service.
Complete Well System
Build It Right Once. Service It More Easily Later.
Shop Merrill Pitless Units →A complete pitless unit creates a strong underground water connection while allowing the pump and internal assembly to be serviced from the top of the well. That means fewer separate components, easier future access, and less risk of costly excavation.