Sewer Accessories

Precast Concrete Grade Rings

Grade Rings provide a way to adjust the manhole to meet finish grade elevation. They are available for 24″ diameter manhole openings. They are available in 2”, 4”, 6”, 12”, 18”, 24” and 36” heights and may be stacked to the desired height. Custom heights are available upon request.

A-LOK Products

We also offer manufactured connectors by A-LOK Products, Inc.

Flexible connectors are designed to produce a positive watertight connection for pipes entering precast manholes and other concrete structures.​

A-Lok and A-Lok X-CEL

Connectors are cast in concrete at the time of manufacture. They function on compression, making field installation quick and easy. A watertight connection is maintained with a 10-degree omnidirectional deflection. Available for pipes from 4 ¼” through 102″ inside diameter. The gaskets meet all material and performance requirements of ASTM C923, ASTM C-478, and ASTM C-1644. 


Z-Lok connectors are flexible pipes to manhole cast in concrete at the time of manufacture and clamped onto the outside of the pipe at the time of installation.  A watertight connection is maintained with a 25-degree omnidirectional deflection. Available for pipes from 1.25″ through 21.25″ outside diameter. The gaskets are manufactured following the requirements of ASTM C923, ASTM C-923, ASTM C1478, ASTM C-1644, and ASTM F-2510

A-Lok STM - Connector for Storm Systems

A flexible gasket that is designed to provide a soil-tight, as well as, watertight connection for round and elliptical pipe entering precast concrete structures. Specifically designed for applications where a high-performance sanitary connector is not necessary. The gasket functions on pure compression will withstand 6 psi. of hydrostatic pressure (equivalent to 13.8 ft of depth).

Dura-Plate 100, Interior PVC lining for corrosion protection

The Dura-Plate 100 is an interior lining for precast concrete structures which combines the immense structural strength and integrity of reinforced concrete with the chemical resistance of polyvinyl chloride. The ribbed liner is integrally cast onto the interior surface of the concrete structure at the time of manufacture. A structure lined with Dura-Plate 100 is assured a long service life under severe conditions, being resistant to H2S, acids, alkalis, and salts which attack sewer systems.

Polypropylene Access Rungs

Walker Industries offers Bowco rungs installed at the plant. Rungs are typically set at 12″ centers running the entire vertical height of the manhole.

Manhole Step

Precast Concrete Flow Channels

Walker Industries provides Flow Channels cast at the plant in round manholes. Channels provide a laminar flow of liquids through the structure. A manhole channel is formed up to the centerline of the pipe.