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  • Polylok Square Septic Tank To Riser Adapter Ring - Part Number 3009-AR
  • Polylok Square Septic Tank To Riser Adapter Ring - Part Number 3009-AR
  • Polylok Square Septic Tank To Riser Adapter Ring - Part Number 3009-AR

Polylok Square Septic Tank To Riser Adapter Ring

The Polylok Square Tank Adapter Ring accepts either 20'' or 24'' risers. The large squared shape of this adapter allows it to cover up to 25'' x 25'' square openings or up to 27'' in diameter round openings. It is recommended to mount this adapter ring to the tank using our Adapter Ring Installation Kit (#ANCHORKIT). Once mounted and sealed to the tank, any combination of Polylok risers and lids will attached directly to this adapter.

In Stock

$76.50MSRP: $89.00

Item #:3009-AR

Manufacturer: Polylok


  • Accepts 20'' or 24'' Polylok Risers and Lids
  • Covers A Maximum Opening of 25'' Square or 27'' Round
  • Large, Flat Surface Area For Easy Tank Mounting

The first component that you need in order to build a complete riser system is the adapter ring. The adapter ring mounts directly to the septic tank, allowing the risers to stack, lock, and mount to it. This piece is important as the risers are not flat on the bottom because they are designed to be stackable, so it is not possible to mount them directly to the septic tank. The adapter ring gives you the flat surface you need to mount to the tank while also being able to accept the stackable risers.

We have two different styles of adapter rings and which one you choose to order will depend on the measurement of your opening. Our square tank adapter ring can cover large square openings up to 25’’ or large round openings up to 27’’. The round tank adapter rings come in 24’’ and 20’’ diameter and are designed to be placed around 24’’ diameter openings or smaller.

OPTIONAL: We sell and highly recommend our Adapter Ring Installation Kit. This kit includes concrete anchors, a masonry bit to install the anchors, and butyl sealant.  Using this installation kit ensures a solid mount and good seal between the adapter ring the septic tank.


1.  Clean tank surface area over opening where riser adapter ring is placed; clear a 36" minimum area for the riser adapter ring. Check plug size for riser clearance.

2.  Place riser adapter ring on tank surface, mark anchor locations through the adapter ring anchor holes. 

3.  Determine the riser size you will use, the 24" position will require removal of the 20" ring.  Turn riser adapter ring over and cut along score line to remove this ring.

4.  Drill hole locations in tank surface and set anchors in place. Anchors can be any of the commonly available anchors.  Anchor kit (optional) is available and includes the drill bit, concrete anchors, bolts, and riser-sealing strip.

5.  On the underside of the riser adapter ring place the riser-sealing strip in position for the riser size used, butyl mastic or silicone sealants can be used.

6.  Place riser adapter ring in position and secure to tank with concrete anchor bolts.

7.  Place additional risers onto riser adapter ring and align screw holes to secure riser sections together.

8. Place riser cover onto top riser and secure with screws provided.

9.  The installation is ready for backfill but you may want to remove riser rings from any addtional risers if FROST is present in your area before final backfill.

Polylok Septic Tank Risers

The Polylok Riser Advantage

Polylok Square Tank Adapter Ring Downloadable Documents