As the name would suggest, above ground septic tanks differ from traditional septic tanks as they are installed and used above the ground’s surface. They are not built for or designed for an effluent leech field and drainage system like underground septic tanks. Rather, aboveground septic tanks are wastewater holding tanks only. They are primarily used to collect and hold sewage derived from human waste, known as blackwater, from toilets, and greywater from sinks and showers until it is time for them to be pumped and serviced.
What are Above Ground Septic Tanks
Above ground septic tanks are small-to-mid-range capacity waste holding tanks designed to hookup to a plumbing system for receiving wastewater in temporary setups or locations unsuitable for underground septic tanks. Some models come prepared for direct hookup with piping, couplers and clamps. Other types require the buyer to prepare and install tank fittings. Most aboveground septic tanks come with at least 1 threaded lid, (i.e., manway) and 2 ports for plumbing hookups. Some models can have up to 4 ports. More ports allow more inlet and outlet connections to be made and are ideal for multi-unit applications where multiple tanks are plumbed together in succession to increase capacity and extend service frequency.
Common Applications for Above Ground Septic Tanks
Above ground septic tanks are often used in areas without municipal sewer lines. Examples include construction sites, temporary job sites, job shacks, agricultural settings, remote homes, trailers, cottages, cabins, hunting posts, campgrounds and RV locations without other hookups or facilities. Aboveground septic tanks have several names that the containers are known by. Their different names also serve as an indication of common application uses. Above ground septic tanks are known as waste holding tanks, job trailer and job shack waste tanks, cottage, trailer, camper and motorhome septic tanks.
Common Uses and Top Features
- Low profile for use in tight spots under structures.
- May be connected in series to increase volume to needed amount.
- Provide waste holding capacity in portable situations.
- Mobile and modular office septic tanks.
- Where standard septic tanks or plumbing are not an option.
- Ideal solution for portable sanitation businesses.
- One-piece, watertight tank and lid.
- No joints or seams to leak or cause problems.
- Will not rust, chip, peel or corrode.
Capacity and Using Above Ground Septic Tanks
Aboveground septic tanks are made and available in holding volume capacity that ranges from 250 gallons up to 1000 gallons. The limited capacity range keeps the tanks smaller in size, making them easier to handle, transport and install. Aboveground septic tanks are used until the tank reaches capacity and then must be emptied. They are often emptied when no more than 2/3 full as it is not recommended to allow an aboveground septic tank to become completely full.
When at max capacity, the tank must be serviced. A septic tank pumping service is usually called to have the holding tank pumped just like an underground septic tank. This is due to how heavy the tank will be at full capacity. In example, a 2/3 full 250 gallon holding tank will weigh well over 1,000 pounds. If maintenance is performed early, a used holding tank may be able to be hoisted or lifted and placed in a truck bed or trailer for transport to a dumping site.
Above ground septic tanks are opaque, often black, tan or yellow in color. They do not feature exterior gallon indicators. To determine if a holding tank is full and it is time to empty, above ground septic tanks must be visually inspected. Tanks come fitted with manways for this to be done.
Table of Above Ground Septic Tank Specifications
Volume (Gallons) | Dimensions (L x W x H) | Liquid Surface Area (Sq. Ft.) | # of Ports | Manufacturer |
105 Gallons | 48″ L x 48″ W x 10.5″ H | 16.00 Sq. Ft. | 0 | NTO |
225 Gallons | 90″ L x 33″ W x 20″ H | 20.62 Sq. Ft. | 2 | NTO |
250 Gallons | 69″ L x 49″ W x 19.5″ H | 23.48 Sq. Ft. | 3 | NTO |
250 Gallons | 84″ L x 40″ W x 17″ H | 23.33 Sq. Ft. | 4 | Quadel |
300 Gallons | 95″ L x 56″ W x 16″ H | 36.94 Sq. Ft. | 3 | Ace Roto Mold |
300 Gallons | 95″ L x 56″ W x 16″ H | 36.94 Sq. Ft. | 3 | NTO |
300 Gallons | 94″ L x 56″ W x 16″ H | 36.94 Sq. Ft. | 0 | NTO |
350 Gallons | 88″ L x 44″ W x 25″ H | 26.88 Sq. Ft. | 4 | Quadel |
440 Gallons | 91″ L x 72″ W x 16″ H | 45.50 Sq. Ft. | 2 | NTO |
500 Gallons | 130″ L x 52″ W x 22″ H | 46.94 Sq. Ft | 2 | Norwesco |
1000 Gallons | 136″ L x 91″ W x 20″ H | 85.94 Sq. Ft. | 2 | NTO |
Design and Manufacture
Above ground septic tanks are manufactured with a low profile design so they can be placed beneath structures such as job trailers, decks and general crawlspaces. Their low profile design also improves access for installing hookups and performing maintenance. Septic handling tanks are molded into a rectangular, wide-area shape that helps distribute the tank’s weight, making it easier to maneuver and allows most models to be moved with just a few people.
Available above ground waste holding tanks are manufactured from quality high-density polyethylene (HDPE) resin. Although made from premium polyethylene plastic, they are not US FDA certified for use with potable (drinking) water and should not be used for drinking water applications. The HDPE construction of above ground septic tanks produces a heavy duty container that does not rust, resists weathering, resists corrosion from sewage gasses and chemicals, and is durable against punctures, drops and impacts. The tanks are engineered for above ground installation and use and should not be buried.
HDPE holding tanks are also fabricated with ultraviolet UV inhibitor compounds that stabilize the plastic against damage and deterioration that exposure to sunlight would otherwise occur. UV blocking compounds approve aboveground holding tanks for outdoor use. UV blockers increase outside service life, allowing the waste tanks to be installed in locations that are not completely away from sun exposure. However, due to the sewage waste these holding tanks are used for, isolating them from sun exposure and heating is often preferred.
Contact Us
National Tank Outlet’s above ground septic tanks are provided with a 3 year manufacturer’s warranty. Some customization options are available. Additional openings, lids, connection inlets and outlets are examples of custom fabrication options and can be provided on request. For polyethylene septic tank questions, custom fabrication or further information, contact us.