Polylok 24" x 12" Septic Tank Riser

The Polylok 24" x 12" Septic Tank Riser (Model 3008-R12) is a versatile, heavy-duty extension riser built for bringing septic tank access to or near ground level with fewer sections. At 12" tall, it's the taller stacking option in the Polylok 24" series—ideal for moderate burial depths or combining with 6" and 2" risers in the Build-a-24 Riser Kit for custom, precise heights.

Constructed from rugged high-density polyethylene (HDPE), this riser offers exceptional durability, UV resistance, and ease of handling compared to concrete alternatives.

POLYLOK RISERS NO LONGER COME WITH A FACTORY INSTALLED GASKET. We recommend using our butyl sealant tape to create a seal between risers.

In Stock

$109.00MSRP: $125.00

Item #:3008-R12

Manufacturer:Polylok

Key Features and Benefits

Tall 12" Profile — Provides substantial height per unit, reducing the number of sections needed for deeper tank lids while maintaining stackability for fine adjustments.
Stackable System — Easily interlocks with other Polylok 24" risers (6", 2", etc.) or adapter rings; build exact heights without cutting or custom fabrication.
Secure Locking — Snaps/locks together and secures with included stainless steel screws (use alternating pattern for even fastening) for a stable, reliable connection.
Watertight and Airtight Capability — Enables effective vacuum or water testing of the septic tank; apply butyl sealant tape (recommended, as factory gaskets are no longer standard on newer units) between sections for optimal sealing against groundwater infiltration.
Reinforced Strength — Features internal structural ribs and reinforcements for added rigidity; supports pedestrian traffic and light loads like lawn mowers or small garden tractors when properly installed and backfilled.
Premium UV Protection — Highest UV-ray resistance on the market to prevent fading, brittleness, or cracking from long-term sun exposure.
Frost-Resistant Design — Includes tear-off rings (where applicable) to help prevent frost adhesion in cold climates.
Lightweight & User-Friendly — Significantly easier to transport, handle, and install than heavy concrete risers, saving time and labor.
Made in the USA — Patented Polylok design from a trusted leader in septic and onsite wastewater products.

Specifications

Diameter: 24 inches (inside diameter)
Height: 12 inches
Material: High-density polyethylene (HDPE)
Color: Green
Compatibility: Works exclusively with Polylok 24" series risers and adapter rings (#3009-AR square tank adapter or #3009-RTR24 round tank adapter). Not interchangeable with other brands without adapters. Note: Some variants feature wall flats (may not accept Polylok safety screens—confirm model if needed).
Included: Riser section + stainless steel attachment screws

Important Note: Polylok risers no longer include factory-installed gaskets as standard—use butyl sealant rope/tape (ASTM-C990 compliant) between joints for a dependable watertight seal.

Easy Installation

Attach base to a compatible Polylok adapter ring secured to the septic tank lid.
Stack and align the 12" riser (or combine with 6"/2" sections) to match your required height from tank to finished grade.
Fasten each connection securely with provided stainless steel screws.
Apply butyl sealant tape between all mating surfaces for airtight/watertight performance.
Top with a Polylok 24" riser lid (sold separately) and backfill carefully for stability.

Perfect for new installations, retrofits, or upgrading buried tank access—eliminate digging hassles during pumping, inspections, or maintenance!