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The Infiltrator IM-1250 is a lightweight strong and durable septic tank. This watertight tank design is offered with Infiltrator’s line of custom-fit risers and heavy-duty lids. Infiltrator injection molded tanks provide a revolutionary improvement in plastic septic tank design, offering long-term exceptional strength and watertightness.

Do not install the tank in vehicular traffic areas. The tank is designed for non-traffic applications.

All IM-1250 tanks are fully assembled and available through our network of certified Infiltrator distributors.

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61.7"W x 152.3"L x 54.6"H
(1567 mm x 3868 mm x 1387 mm)

Two Access Ports
Each 24" (610 mm)

405 lbs (184 kg)

Total Capacity
1480 gal (5602 L)

Working Capacity
1278 gal (4839 L)

Burial Depth
Minimum 6" (152 mm)
Maximum 48" (1219 mm)


  • Strong injection molded polypropylene construction
  • Lightweight plastic construction and inboard lifting lugs allow for easy delivery and handling
  • Structurally reinforced access ports eliminate distortion during installation and pump-outs
  • Reinforced structural ribbing and fiberglass bulkheads offer additional strength
  • Can be installed with 6" to 48" of cover
  • Can be pumped dry during pump-outs
  • Suitable for use as a septic tank, pump tank, or rainwater (non-potable) tank
  • No special installation, backfill or water filling procedures are required
  • No special water filling requirements are necessary
  • The tank may be backfilled with suitable native soil. See installation instructions for guidance.

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