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Plastic Septic Tanks


Plastic Septic Tanks

Plastic-Mart's septic tanks for sale are long-lasting, are easy to install, and are cost-effective. As one of the top septic tank suppliers, we offer a wide range of plastic septic holding tanks such as 500 gallons or 1000 gallon storage containers. Today's technology and engineering involved with making a plastic septic tank, has created a product built to last.

Plastic Septic Tanks are designed for both residential and commercial use. Plastic Septic Tanks may NOT be used for storage of chemicals intended for human consumption, if needed see the below ground food grade water cistern tanks.

Browse through our septic tanks and septic tank accessories and purchase yours today!


Types of residential and commercial uses for plastic septic tanks:
  • Outhouses
  • Trailers
  • RV parks
  • Homes
  • Cottages
  • Portable construction buildings

Plastic Septic Tanks vs. Concrete

Plastic holding tanks and concrete tanks have multiple, significant differences.

Plastic septic tank installation is less complicated and can be stored in a wide variety of places. Septic tanks constructed by polyethylene resins are less susceptible to cracking too.

Concrete septic tanks are more expensive, crack easily, and can be challenging to repair.

The Advantages of Double Compartment Poly Septic Tanks

Dual compartment septic holding tanks provide more storage for waste which means that you do not have to empty the tank as often as a single poly septic tank.

Double compartment plastic septic tanks provide an additional area for sludge and liquid. The partition opening allows for solids and liquids to flow into the second area.

When the first compartment of a dual holding septic tank is filled to the top, the waste begins to flow into the second compartment. Solids then have more time to settle. With our double compartment septic tanks for sale, you save more time and more money!



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Name Capacity Dimensions Part Price
200 Gallon Plastic Septic Pump Tank (43745) 200 Gallons 47" dia x 56"H N-43745 $535.00
200 Gallon Plastic Septic Pump Tank (Austin TX)
(Ships In 48 Hours)
200 Gallons 47" dia x 56"H 9504-N-43745 $535.00
200 Gallon Plastic Septic Pump Tank (43745)
(Ships In 48 Hours)
200 Gallons 47" dia x 56"H 9516-N-43745 $535.00
300 Gallon Sphere Pump Tank (41319)
Ships In 48 Hours
300 Gallons 54" dia x 54"H N-41319 $747.00
300 Gallon Sphere Pump Tank - Nonplumbed 300 Gallons 48-1/2" Dia. x 53"H SII-5260000W94201 $782.00
300 Gallon Plastic Septic Pump Tank 300 Gallons 54"dia. x 56"H A-AST-0300-1 $673.14
300 Gallon Plastic Septic Pump Tank 300 Gallons 54"dia. x 56"H A-AST-0300-1R $491.91
300 Gallon Sphere Pump Tank - Preplumbed 300 Gallons 48.5"L x 48.5"W x 53"H SII-ST11S $962.00
300 Gallon Sphere Pump Tank - Preplumbed
Ships In 48 Hours (*Restricted)
300 Gallons 48.5"L x 48.5"W x 53"H 9525-SII-ST11S $962.00
300 Gallon Black Above Ground Holding Tank
(Ships In 48 Hours)
300 Gallons 95"L x 56"W x 16"H 9503-A-LP0300-HT-BLK $686.00
500 Gallon Low Profile Plastic Septic Tank
Ships In 48 Hours
500 Gallons 97" L x 48" W x 42" H N-43522 $1,055.00
500 Gallon Low Profile Septic Tank (San Antonio TX)
(Ships In 48 Hours)
500 Gallons 97" L x 48" W x 42" H 9516-N-43522 $1,055.00
500 Gallon Low Profile Septic Tank (Austin TX)
(Ships In 48 Hours)
500 Gallons 97" L x 48" W x 42" H 9504-N-43522 $1,055.00
500 Gallon Low Profile Septic Tank (Houston TX)
(Ships In 48 Hours)
500 Gallons 97" L x 48" W x 42" H 9513-N-43522 $1,055.00
500 Gallon Low Profile Septic Tank (San Antonio TX)
(Ships In 48 Hours)
500 Gallons 97" L x 48" W x 42" H 9514-N-43522 $1,055.00
500 Gallon Low Profile Septic Tank (Oklahoma)
Ships Soon
500 Gallons 97" L x 48" W x 42" H 9539-N-43522 $1,055.00
500 Gallon Sphere-Pump/Dosing Tank (40785) 500 Gallons 64" dia. x 67"H N-40785 $933.00
525 Gallon Low Profile Spherical Pump Tank 525 Gallons 64"L x 64"W x 67"H N-44831 $1,057.00
500 Gallon Plastic Septic Tank - 1 Compartment 500 Gallons 101" L x 51" W x 47" H N-41320 $1,061.00
500 Gallon Plastic Septic Pump Tank 500 Gallons 63"dia. x 74"H A-AST-0500-1 $933.00
500 Gallon Sphere Pump Tank - Nonplumbed 500 Gallons 60" Dia. x 63"H SII-PT2S $862.00
500 Gallon Sphere Tank - Preplumbed 500 Gallons 60"L x 60"W x 63"H SII-ST21S $1,040.00
750 Gallon 2 Compartment NexGen Septic Tank (IAPMO) 750 Gallons 92" L x 60" W x 51" H N-44510 $1,785.00
750 Gallon Septic Tank - 1 Compartment / 2 Manholes 750 Gallons 96" L x 48" W x 63" H N-41814 $1,607.00
750 Gallon One Compartment Plastic Septic Tank 750 Gallons 70"L x 60"W x 60"H A-AST-0750-1 $1,169.48
750 Gallon 1 Compartment Plastic Septic Tank (Loose Plumbing) 750 Gallons 92" L x 60" W x 51" H N-43495 $1,515.00
750 Gallon 1 Compartment NexGen Septic Tank (Loose Plumbing) 750 Gallons 92" L x 60" W x 51" H SII-43495 $1,667.00
750 Gallon 1 Compartment Plastic Septic Tank (Preplumbed) 750 Gallons 92" L x 60" W x 51" H N-43520 $1,825.00
750 Gallon 2 Compartment Plastic Septic Tank (Loose Plumbing) 750 Gallons 92" L x 60" W x 51" H N-43499 $1,671.00
750 Gallon 2 Compartment Plastic Septic Tank (Loose Plumbing)
(Ships In 48 Hours)
750 Gallons 92" L x 60" W x 51" H 9504-N-43499 $1,671.00
750 Gallon 2 Compartment NexGen Septic Tank 750 Gallons 92" L x 60" W x 51" H SII-43499 $1,791.00
750 Gallon 2 Compartment NexGen Septic Tank (IAPMO)
Ships In 48 Hours (*Restricted)
750 Gallons 92" L x 60" W x 51" H 9525-SII-44510 $1,785.00
750 Gallon 2 Compartment Septic Tank (Preplumbed)
Ships Soon
750 Gallons 92" L x 60" W x 51" H N-43521 $1,866.99
750 Gallon 2 Compartment Septic Tank (Preplumbed) (Buda TX)
(Ships In 48 Hours)
750 Gallons 92" L x 60" W x 51" H 9516-N-43521 $1,866.99
1000 Gallon 2 Compartment NexGen Septic Tank (IAPMO) 1000 Gallons 127" L x 60" W x 51" H N-44482 $2,009.00
1000 Gallon Plastic Septic Tank - 1 Compartment 1000 Gallons 102" L x 60" W x 58" H N-41718 $1,785.00
1000 Gallon Plastic Septic Tank - 1 Compartment 1000 Gallons 101"L x 60"W x 60"H A-AST-1000-1 $1,629.38
1000 Gallon Plastic Septic Tank - 2 Compartment 1000 Gallons 102" L x 60" W x 58" H N-41720 $1,916.00
1000 Gallon Two Compartment Plastic Septic Tank 1000 Gallons 101"L x 60"W x 60"H A-AST-1000-2 $1,882.60
1000 Gallon 1 Compartment Plastic Septic Tank (Loose Plumbing) 1000 Gallons 127" L x 60" W x 51" H N-42405 $1,565.00
1000 Gallon 1 Compartment NexGen Septic Tank 1000 Gallons 127" L x 60" W x 51" H SII-42405 $1,806.00
1000 Gallon 1 Compartment Plastic Septic Tank (Preplumbed) 1000 Gallons 127" L x 60" W x 51" H N-43496 $1,964.00
1000 Gallon 2 Compartment Plastic Septic Tank (Loose Plumbing) 1000 Gallons 127" L x 60" W x 51" H N-43517 $1,685.00
1000 Gallon 2 Compartment Plastic Septic Tank (Preplumbed)
Ships Soon
1000 Gallons 127" L x 60" W x 51" H N-42406 $1,994.99
1000 Gallon 2 Compartment Plastic Septic Tank (Preplumbed)
(Ships In 48 Hours)
1000 Gallons 127" L x 60" W x 51" H 9513-N-42406 $1,994.99
1000 Gallon 2 Compartment Plastic Septic Tank (Preplumbed)
(Ships In 48 Hours)
1000 Gallons 127" L x 60" W x 51" H 9514-N-42406 $1,994.99
1000 Gallon 2 Compartment Plastic Septic Tank (Preplumbed)
(Ships In 48 Hours)
1000 Gallons 127" L x 60" W x 51" H 9516-N-42406 $1,994.99
1000 Gallon 2 Compartment Plastic Septic Tank (Preplumbed)
Ships In 48 Hours
1000 Gallons 127" L x 60" W x 51" H 9515-N-42406 $1,994.99
1175 Gallon Underground Water Cistern Storage Tank
(Ships In 48 Hours)
1175 Gallons 127" L x 60" W x 51" H 9526-N-44405 $2,045.00
1250 Gallon 2 Compartment NexGen Septic Tank (IAPMO) 1250 Gallons 157" L x 60" W x 51" H N-44483 $2,976.00
1250 Gallon Plastic Septic Tank - 2 Compartment 1250 Gallons 116" L x 55" W x 70" H N-41744 $2,337.00
1250 Gallon 1 Compartment Plastic Septic Tank (Loose Plumbing) 1250 Gallons 157" L x 60" W x 51" H N-43519 $2,159.00
1250 Gallon 1 Compartment NexGen Septic Tank 1250 Gallons 157" L x 60" W x 51" H SII-43519 $2,297.00
1250 Gallon 1 Compartment Plastic Septic Tank (Preplumbed) 1250 Gallons 157" L x 60" W x 51" H N-43497 $2,456.00
1250 Gallon 2 Compartment Plastic Septic Tank (Loose Plumbing) 1250 Gallons 157" L x 60" W x 51" H N-43503 $2,304.00
1250 Gallon 2 Compartment Plastic Septic Tank (Loose Plumbing)
(Ships In 48 Hours)
1250 Gallons 157" L x 60" W x 51" H 9504-N-43503 $2,304.00
1250 Gallon 2 Compartment Plastic Septic Tank (Preplumbed) 1250 Gallons 157" L x 60" W x 51" H N-43501 $2,611.00
1500 Gallon 2 Compartment NexGen Septic Tank (IAPMO) 1500 Gallons 157" L x 69" W x 51" H N-44484 $3,528.00
1500 Gallon Plastic Septic Tank - 1 Compartment 1500 Gallons 135" L x 55" W x 70" H N-41758 $2,675.00
1500 Gallon Bruiser Septic Tank - 2 Compartment 1500 Gallons 135" L x 55" W x 70" H N-41772 $3,353.00
1500 Gallon Plastic Septic Tank - 2 Compartment 1500 Gallons 135" L x 55" W x 70" H N-41760 $2,695.00
1500 Gallon 1 Compartment Plastic Septic Tank (Loose Plumbing) 1500 Gallons 157" L x 69" W x 51" H N-43518 $2,547.00
1500 Gallon 1 Compartment NexGen Septic Tank 1500 Gallons 157" L x 69" W x 51" H SII-43518 $2,720.00
1500 Gallon 1 Compartment Plastic Septic Tank (Preplumbed) 1500 Gallons 157" L x 69" W x 51" H N-43498 $2,880.00
1500 Gallon 2 Compartment Plastic Septic Tank (Loose Plumbing) 1500 Gallons 157" L x 69" W x 51" H N-43504 $2,571.00
1500 Gallon Norwesco 2 Compartment Septic Tank 1500 Gallons 135"L x 55"W x 70"H N-44481 $2,758.00
1500 Gallon Norwesco 2 Compartment Septic Tank 1500 Gallons 135"L x 55"W x 70"H N-44480 $2,730.00
1500 Gallon 2 Compartment Plastic Septic Tank (Preplumbed) 1500 Gallons 157" L x 69" W x 51" H N-43502 $2,935.99
1500 Gallon 2 Compartment Plastic Septic Tank (Preplumbed)
(Ships In 48 Hours)
1500 Gallons 157" L x 69" W x 51" H 9514-N-43502 $2,935.99
1500 Gallon 2 Compartment Plastic Septic Tank (Preplumbed)
(Ships In 48 Hours)
1500 Gallons 157" L x 69" W x 51" H 9516-N-43502 $2,935.99
1725 Gallon Underground Water Cistern Storage Tank
(Ships In 48 Hours)
1725 Gallons 157" L x 69" W x 51" H 9503-N-44407 $3,084.00
1725 Gallon Underground Water Cistern Storage Tank
(Ships In 48 Hours)
1725 Gallons 157" L x 69" W x 51" H 9526-N-44407 $3,084.00
2000 Gallon Underground Holding Tank 2000 Gallons 126" L x 98"W x 51"H N-44593 $4,493.00
2500 Gallon Underground Holding Tank 2500 Gallons 159"L x 99"W x 51"H N-44079 $5,793.00
2600 Gallon Underground Holding Tank 2600 Gallons 155" L x 98"W x 51"H N-43770 $5,910.22
2650 Gallon Underground Holding Tank 2650 Gallons 155" L x 98"W x 81"H N-43771 $6,394.00
3525 Gallon Underground Holding Tank 3525 Gallons 211" L x 102" W x 51" H N-44390 $9,429.00
5025 Gallon Underground Holding Tank 5025 Gallons 211" L x 102" W x 73" H N-44876 $12,529.00
10000 Gallon Below Ground Holding Tank 10000 Gallons 356"L x 101"W x 107"H N-45686 $21,081.00
1000 Gallon Norwesco - 2 Compartment Septic Tank 1000 Gallons 102"L x 60"W x 63"H N-44475 $1,943.00
ADS ARC 24 Type Septic Leaching Chamber
(Ships In 48 Hours)
60"L x 24"W x 12"H 9516-ADS-2412BD $45.02
6" NexGen Manhole Extension
(Ships In 48 Hours)
9520-SII-63832 $121.00
15" NexGen Riser Extension
(Ships In 48 Hours)
9520-SII-63833 $142.00
24" NexGen Manhole Extension
(Ships In 48 Hours)
9520-SII-63834 $163.00



What is the purpose of a Double Compartment Septic Tank?

Aside from differences in capacity between the one and two compartment poly septic tanks, the way in which water flows and collects in your tank is distinct. A second compartment allows more room to settle the solids and liquids in the tank.

In a single compartment tank, one chamber that holds all liquid, sludge and scum. Adding a second compartment provides an additional area for you sludge and liquid to exist. Typically the two compartments are separated by a baffle partition. The partition opening allows for a select amount of liquid to flow into the secondary area. Once liquids inside the septic tank reach the height of the opening, flow into the second chamber begins.

This permits solids more time to settle, allows extra storage space septic waste. As opposed to a single compartment, the extra compartment gives you more space and more time before you need to empty the tank.

double compartment septic tanks


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