Plastic Septic Tanks: General Installation Guidelines

These polyethylene septic tank installation guidelines are generic; always check with the manufacturer of the poly septic tank to see if any specific instructions are necessary.

JoJo septic tanks

Siting of the poly septic tank:

  • The sewage system should be as far away from habitable buildings as is economically possible.
  • Good road access should be provided to enable tank-emptying vehicles to operate its suction-lift capabilities.


  • Trench shall be excavated to approximate size of the plastic septic tank.
  • The bottom of the trench should be level and there should be no sharp rocks.
  • Recommended coverage over the tank should be approximately 18″ (about 500mm).
  • Second trench approximately the size of the septic tank should be excavated for the soak away-pit.
  • This soak away-pit should be approximately 3m away from the plastic septic tank.
  • Preferably made in the direction of flow of water.

Plastic septic tank installation:

  • The septic tank should be lowered slowly into the pit. (Ensure base is completely even with no sharp objects.)
  • It is recommended that piping connection is made at least 18″ below ground level and checked.
  • Fill the poly septic tank with water, till water flows into the soak-away pit. (This is required during installation).

Back-fill for Septic Tanks:

  • Material should be free of sharp rocks.
  • Material should be packed (by hand or foot) at the base evenly.
  • Plastic septic tank should be filled with water.
  • If installation is in soils that leave large voids on back filling, it should be packed with gravel or sand.

Back-fill for soak-away pit:

  • Trench should be packed with large rocks.
  • The top 18″ or so should be packed with finer gravel and then mud to ensure attractive surroundings.

NB: Safety:

It is recommended that heavy equipment should not be operated over any septic tank system. It is suggested that the area should be adequately fenced to prevent potential accidents and unauthorized interference.

Source: RotoTanks

JoJo Tanks (South Africa) manufacture a wide range of polyethylene products, including plastic septic tanks which are available in the following capacities: 1250 liter, 1500 liter, 1750 liter, 2000 liter, 2500 liter and 6000 liter.  jojo plastic septic tanks

The 6000 liter septic tank (also available in conservancy tank and underground water tank versions) requires very specific installation procedures (available on purchase of this septic tank).  This high capacity septic tank is recommended for 10 or more people and has the following dimensions: diameter = 1900mm, height = 1980mm, length = 3330mm, manhole = 450mm.

JoJo Tanks South Africa offer a wide range of products such as plastic water tanks and chemical tanks to suit every household, business or agricultural need, including silo tanks and silo tank stands as well as other high quality JoJo Tanks products.  See JoJo Tanks’ VERTICAL TANKS, HORIZONTAL TANKS (transporter tanks), STEEL TANK STANDS and OTHER JOJO PRODUCTS and see JoJo Tanks’ NEW 6000 LITRE UNDERGROUND TANKS. Also see our FAQ and WATER TANK PRICES.

JoJo’s superior polyethylene plastic water tanks and steel water tank stands make JoJo Tanks the leaders in plastic water tank technology and the quality, affordability and 5-year guarantee on these water tanks make JoJo products one of the best choices in South Africa.  *All JoJo Tanks polyethylene tanks and products now carry a 8 year warranty (on tanks purchased on or after 1 July 2013)*  JoJo’s water tanks and chemical tanks come standard with a number of features that are often lacking on cheaper/inferior plastic tanks made by other companies in South Africa.

We are authorised JoJo Tanks dealers in South Africa and dispatch orders directly from JoJo Tank depots to save on transport costs. Full range of JoJo Tanks products and JoJo water tanks for sale.  CONTACT US for a quote on the right JoJo water tank or other JoJo product for you.  Special discounts are available on multiple orders of chemical tanks and water tanks and to our commercial and government customers. We can usually delivery tanks and tank stands free of charge to business/commercial addresses in South Africa.


(15000 litre and 20000 litre JoJo vertical water tanks & chemical tanks are available on order directly from JoJo Tanks’ main factory)

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