Below Grade Transition Sumps

Below Grade multi-body transition sumps are some of the most versatile sumps in the marketplace. The epoxy trough eliminates field fiberglass work and the square design offers large piping surfaces. Many combinations of bases and risers available to best suit individual jobsite requirements. The TSM series also features optional collar mount bases for use as tank sumps, expanding the versatility of the product line.

Custom Sizes Available
Various sizes and options are available to meet any job-site or customer specifications upon request.

Collar mount bases allow the TSM Series to be used as tank sumps.

UL Listed 2447

  • TSM484860

Standard Features

100% Fiberglass

100% high-quality, non-corrosive fiberglass provides long-term reliable containment from fuel exposure without voiding warranty, warping, cracking or becoming brittle.

Duo Molded Technology

Duo-Molded Technology

Our fiberglass sumps utilizes Duo-Molded Technology. Using premium raw materials with a high glass content, we create two layers of fiberglass, offering superior strength and fuel resistance.


Our signature ‘Brite-White’ interior reflects light for better visibility and makes identifying leak points easier.

TwistLok Access Cover Logo

Twist-Lok Access Cover

PCI’s tank sumps come standard with the latest generation of our innovative ‘Twist-Lok’ Access Cover. Constructed from injection molded fiberglass, Twist-Lok lids provide a watertight seal with a quick and easy 12º  turn.


Part No. Double Wall Base Height (A) Adjustable Height (B) Overall Height (C) Width (D)
TSM484836B TSMDW484836B 18” 4” – 18” 32” – 46” 48”
TSM484848D TSMDW484848D 30” 4” – 18” 44” – 58” 48”
TSM606048D TSMDW606048D 30” 4” – 18” 44” – 58” 60”
TSM606060D TSMDW606060D 30” 4” – 30” 44” – 70” 60”
TSM484836BU TSMDW484836BU 18” 4” – 18” 38” – 52” 48”
TSM484848DU TSMDW484848DU 30” 4” – 18” 50” – 64” 48”
TSM606048DU TSMDW606048DU 30” 4” – 18” 50” – 64” 60”
TSM606060DU TSMDW606060DU 30” 4” – 30” 50” – 76” 60”
-3B0 Solid Bottom, No Bonding Kit
-3B1 Solid Bottom, E148CM Epoxy Kit
-3C0* 42” Collar Mount, No Bonding Kit
-3C2* 42” Collar Mount, E142CM / E148CM Epoxy Kit
-3D0** 48” Collar Mount, No Bonding Kit
-3D2** 48” Collar Mount, E142CM / E148CM Epoxy Kit
-3E0** 54” Collar Mount, No Bonding Kit
-3E2** 54” Collar Mount, E142CM / E148CM Epoxy Kit

Additional Models and Options Available
* 42″ Collar mount options are available on TSM4848XXU and TSM6060XXU models only
** Only available for TSM6060XXU models
Universal Bottom adds 6″ to height

Additional Accessories (Ordered Separately)

Part No. Description
EQP-DW-VAC Vacuum Kit (Required for all Double Wall Sumps)
EQP-IF-5GAL Interstitial Fluid, 5 Gallons (Required for Double Wall Sumps with Fluid Filled Interstice)
EQP-IF-ADP-PC Interstitial Fluid Adapter Kit (Required for Double Wall Tank & Below Grade Transition Sumps)
Double Wall Tank Sump Dimensions



UL® Listed 2447

California Code of Regulation Title 23, Division 3, Chapter 16, Section 2631 (AB 2481/ California VPH)

State of Floria Department of Environmental Protection Approved / Registered Storage Tank System: EQ-203

Installation Video