Pitless Adapters

Pitless adapters connect the drop pipe running from a submersible well pump to the horizontal service line, providing a watertight fitting installed below the frost line so the connection never freezes. The two-piece design slides together to form a sealed joint, and it lets a technician pull the pump and drop pipe straight up out of the casing for service without digging up the buried horizontal run. Well contractors use these fittings on nearly every submersible pump installation that needs a frost-safe, code-compliant wellhead connection.

Sizing depends on both the well casing diameter and the drop pipe size, with common casing sizes running from 4 inches to 8 inches and drop or discharge pipe commonly in 3/4 inch, 1 inch, or 1-1/4 inch. Matching both dimensions correctly is what allows the two halves of the adapter to seat and seal properly once installed.

Subcategories

• Brass Pitless Adapters: Brass pitless adapters are a common choice for residential well installations, built from solid brass with gaskets and O-rings to form the watertight seal between the two halves. Well contractors use brass adapters on standard residential drop pipe sizes of 3/4 inch, 1 inch, and 1-1/4 inch. The brass body resists corrosion in typical groundwater conditions. Casing hole sizes for these adapters are commonly 1-3/4 inch or 2-1/8 inch.
• Stainless Steel Pitless Adapters: Stainless steel pitless adapters offer additional durability over brass in more corrosive groundwater or soil conditions. Contractors select stainless construction for wells where water chemistry or soil conditions would shorten the service life of a brass fitting. The two-piece slide-together design functions the same as the brass version. Stainless adapters are available in the same common drop pipe sizes used across the category.
• Double-Hole Pitless Adapters: Double-hole pitless adapters provide two separate penetrations through the well casing, commonly used when a well needs both a discharge line and a separate line for equipment like a pressure sensor or additional pump wiring. This configuration requires a single, larger casing penetration rather than two separate holes. Well contractors use this style on installations with more complex wellhead requirements. Sizing still follows the same drop pipe dimension standards as single-hole adapters.

Buying Guide

Start by confirming the well casing diameter, since pitless adapters are sized to match specific casing dimensions, commonly ranging from 4 inches up to 8 inches or larger. An adapter sized for the wrong casing diameter will not create a proper watertight seal once installed.

Next, match the drop pipe and discharge pipe size to the adapter. Pitless Adapters are typically available in 3/4 inch, 1 inch, and 1-1/4 inch drop pipe sizes, and this dimension needs to match the pump's discharge connection as well as the piping running to the service location.

Decide on material based on groundwater and soil conditions at the site. Brass construction with gaskets and O-rings covers most standard residential installations, while stainless steel offers better durability in more corrosive conditions.

Consider whether the installation needs a single-hole or double-hole configuration. A double-hole adapter accommodates a separate line for equipment like a pressure sensor alongside the main discharge line, which single-hole adapters cannot support without an additional casing penetration.

Finally, verify local well code requirements for frost line depth and installation practices before finalizing the order, since pitless adapter installation depth and configuration can be subject to local regulation depending on the jurisdiction.

Frequently Asked Questions

What does a pitless adapter actually do?

It provides a watertight connection below the frost line between the drop pipe from a submersible pump and the horizontal service line. This keeps the connection from freezing and allows the pump to be serviced without digging up the buried pipe run.

What sizes do pitless adapters come in?

Casing sizes commonly range from 4 inches to 8 inches, while drop and discharge pipe sizes are typically 3/4 inch, 1 inch, or 1-1/4 inch. Both dimensions need to be confirmed before ordering.

What is the difference between brass and stainless steel pitless adapters?

Brass adapters use gaskets and O-rings and cover most standard residential installations, while stainless steel adapters offer additional corrosion resistance in more aggressive groundwater or soil conditions.

When is a double-hole pitless adapter needed?

A double-hole adapter is used when a well needs a separate penetration for equipment like a pressure sensor in addition to the main discharge line. A single-hole adapter only supports the discharge line itself.

Can a pump be serviced without digging up the pitless adapter?

Yes, the two-piece design allows the pump and drop pipe to be pulled straight up out of the casing for service. The buried horizontal line and adapter body stay in place during routine pump maintenance.