Septic Tanks for Sale | 300 to 1500 Gallon | IAPMO

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Ronco

Custom Roto-Molding | Seamless Septic & Holding Tanks

Chem-Tainer

Norwesco

Trionic

Ultratech

Enduraplas Poly Tanks | Plastic Water Tanks | WST

AK Industries

ATI

Texas Metal Tanks

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Ronco

Custom Roto-Molding | Seamless Septic & Holding Tanks

Chem-Tainer

Norwesco

Trionic

Ultratech

Enduraplas Poly Tanks | Plastic Water Tanks | WST

AK Industries

ATI

Texas Metal Tanks

SITE TANKS

Powerblanket

Western Global

One Clarion

Core & Main

Wylie

IMACC

Newberry Tanks

Quadel

Simpson

FNA Group

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Light blue co septic tank with standard septic tank sizes

Septic Tanks for Sale

Tank Superstore carries poly septic tanks from 300 to 1500 gallons, in single and double compartment designs, with IAPMO certified models across the range. Every tank ships ready for installation, and pre-plumbed models arrive with inlet and outlet fittings already in place. These tanks serve homes, cabins, cottages, RV parks, outhouses, and portable construction buildings.

Septic approvals vary by state, so confirm the rating your county requires before ordering. Our septic tanks by state page lists which tanks are approved where.

Explore our range of septic tanks and accessories, and secure your purchase today! Suitable for various residential and commercial uses, including outhouses, trailers, RV parks, homes, cottages, and portable construction buildings.

Experience the benefits of double-compartment poly septic tanks. These tanks offer increased waste storage capacity, reducing the frequency of tank emptying compared to single poly septic tanks. The dual compartments provide an additional space for sludge and liquid, allowing for the efficient flow of solids and liquids into the second area.

As the first compartment fills to capacity, waste seamlessly transitions into the second compartment, providing more time for solids to settle. Opt for our double-compartment septic tanks for sale and enjoy both time and cost savings!

Underground Septic Tanks

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Choosing the Right Septic Tank

Single or double compartment. A single compartment tank holds all waste in one chamber and suits smaller households and lower daily flow. A double compartment tank adds a second chamber that gives solids more time to settle before liquid moves to the drainfield, which is why many states now require dual compartment designs for new residential systems. Browse single compartment tanks and double compartment tanks.

Standard duty or heavy duty. Standard duty tanks handle typical residential burial conditions. Heavy duty tanks use a thicker wall for deeper burial, heavier soil loads, and commercial sites. Use the Standard Duty and Heavy Duty filters above to compare both builds of the same tank.

Septic tank or holding tank. A septic tank discharges treated liquid to a drainfield. A holding tank does not discharge at all and must be pumped out, which makes it the right choice for sites without a drainfield. If your site has no drainfield, shop septic holding tanks instead.

Burial and installation. All tanks in this department are designed for underground installation. For burial depth ratings and lid riser options, see underground septic tanks. Covers, risers, and effluent filters are in septic tank accessories.

Septic Tank Questions

What size septic tank do I need? Tank size depends on bedroom count and estimated daily flow, and most states set a minimum size for new home systems. Our septic tank sizing guide walks through the sizing math and typical state minimums.

Are these tanks certified? IAPMO certified models are available across the range, and certification is noted on each product page. Your county may require a specific approval, so confirm the rating your permit calls for before ordering.

Can a plastic septic tank be buried? Yes. These polyethylene tanks are engineered for direct burial, with heavy duty builds available for deeper installations and heavier soils. Follow the bedding and backfill instructions for your model to protect the warranty.

How do I get help choosing? Send us a quote request with your state, household size, and site conditions, and our team will confirm which approved tank fits your system.

What our customers say

Purchased a boat tank and a fittings kit. Both items arrived promptly and in excellent condition. Very satisfied with the quality of service.

Zack E.
Excellent service! I bought a spill pallet, and the staff was incredibly helpful and kind. They took the time to answer all my questions and made the process very easy.

Nick P.
Very happy with my experience ordering the drum rack system was quick and easy, and it arrived right on time, excellent service!

Erin W.
Purchased a couple of cone bottom tanks the process was fast and the service was excellent. They provided great support in helping us select the best option.

Matthew B.
We purchased a 200-gallon double-wall tank, and it arrived right on schedule. Very satisfied with the service!

John S.
Purchased 15 IBC tote tanks for our company. We were very pleased with the competitive pricing and the overall value.

David R.