Absorption Trench Services

Your absorption trench is a crucial but often overlooked piece of your septic tank systems operation.

The absorption trench is where the treated effluent from your septic system is disposed of once solid material has been separated inside your tank.

Effluent flows from your septic tank to the absorption trench area usually by means of a gravity feed. This is whereby a combination of friendly bacteria in the soil, plant root interaction and sunshine, the effluent is broken down and made safe before being put back into the environment.

If your septic tank system is overdue for a clean, untreated waste can flow into your absorption trench and limit its ability to effectively dispose of the effluent from your tank.

The solid material that should be contained in your septic tank can flow into your drain field where it blocks the holes that normally allow effluent to pass into the soil of your absorption trench for clean, efficient and safe disposal.

Before engaging anyone to work on your Absorption Trench, please check that they have either a current Plumbers or Drainers Contactor License.

Any reputable professional will be licenced and will be happy to show you proof of their current (Plumbers or Drainers) Contactor License. For your own safety and your peace of mind, make certain your contractor is correctly Licenced before you make any commitment.

Signs of this problem occurring are many. They can include wet and soggy ground above your absorption trench or unpleasant smells from around your trench field area. Your absorption trench and the surrounding area should be dry and have no unsightly odours.

Depending on the severity of the blockages to your absorption trench system should this problem exist, may well require rehabilitation or replacing of your absorption trench altogether, to make it safe and effective once again. Like most things, prevention is far better than cure. Taking care when installing or replacing your absorption Trench is no different.

Making sure the right location is for your absorption trench is selected, to begin with, the construction of the trench itself is best practice. These things will help ensure you have little or no trouble from your system for the longest possible time.

A well designed and maintained absorption trench will last 25 to 30 years without a problem.

In the same token, a trench which is subject to the trials of a poorly maintain septic system or poor construction or design, to begin with, can become useless (and a health hazard) in as little as two years of use.

I have seen this a lot.


Septic tanks and their absorption trench system elements are a big investment and they work hard every day. When you get them done right, this investment over a 30-year period can stretch every dollar spent as far possible and actually save you big time on a quick fix.

If you are having trouble with an absorption trench problem or even an issue with septic tank cleaning where you really need some expert help. Give me a call (Paul Burgess on 0438 315 514).

Being a licenced plumber and drainer, combined with my years of experience installing and maintaining septic systems allows me to provide the expertise required to make sure you get your absorption trench problems fixed properly.

I have been in the business for over four decades and I know this stuff inside and out. Don’t risk a quick fix. These inevitably cost a lot more money.

Give me a call to discuss your septic and absorption trench needs, I will be happy to share my experience with you and give you the lowdown on what you need.

Do you need help with your absorption trench problems?

Call a licensed plumber, drainer & septic tank system expert now!

Absorption Trench Problems » Absorption Trench

Absorption Trench Installation FAQs

Working with Absorption Trenches and cleaning septic systems, helping people solve their Absorption Trench problems is a regular occurrence for me. I am asked lots of questions about Absorption Trenches and have tried to answer some of the more popular questions I get asked here for you.

To help clear the water (bad pun I know…)

Anyway, the information here is to explain in regular terms the answers to questions you may have about your septic system and the very important Absorption Trench component that helps to make it all work. And with the proper care, you will hardly have to think about it for up to 5 years at a time, so long as things are set up right from the word GO.

Your Absorption Trench is an extremely important part of your Septic System. The absorption trench is where all the effluent processed in your septic tank system is put back into the environment in a clean and safe way. An absorption trench is an environmentally sustainable system that if created properly can last for up to 30 years or more without the need for human intervention at all.   

This doesn’t mean your septic system can go for this amount of time without a clean. Solid wastes must be cleaned out (septic tank pumping) about every 5 years to keep them healthy.  

This is important. A septic system left too long between cleanouts can start to send solid material down the line to your absorption trench and block the trenche’s ability to effectively dispose of effluent (liquid septic waste) into the surrounding soil. This is where the harmful bacteria is neutralised by soil, plants and the sun. The remaining effluent becomes a valuable nutrient for the surrounding soil.

When your absorption trench does start to get blocked with solid waste from your septic tank, you start to get unpleasant smells around the absorption trench “drain field” where your trench is located. This will eventually lead to the ground getting soft and soggy and in the worst case allow untreated effluent to sit on top of the absorption trench field where it can become a major health hazard.

This, if left unchecked,  will lead to the ground around your absorption trench getting soft and soggy. In the worst case allowing untreated effluent to sit on top of the absorption trench field (above ground) where it can become a major health hazard.

This can also leave your old absorption trench useless and in need of replacement.

There are many factors that influence the size an absorption trench needs to be, to be effective. The short answer is the more load you place on your trench and septic system, the larger it has to be. Factors like the number of people living in your home, the type of soil that your trench is located in, the contour of the land ( and how well it drains), how large a plot of land your drain field is located in and the type of foliage that surrounds it (large tree, shrubs etc.).

The short answer is, you will know that your absorption trench needs help when the ground around your trench, the “Drain Field” is wet, soggy and smelly. This is most often the result of solid material (sludge) from your septic system flowing out with the effluent (the treated liquid waste from your septic system – grey water) into your absorption trench.

Your absorption trench is designed to let the liquid effluent pass through the trench into the surrounding soil through small holes in the pipes that make up your drain field system. The solid material that overflows into your drain field (absorption trench) when your septic tank is too full and needs servicing acts to clog the holes and prevents the effluent from correctly dissipating.

This will eventually destroy the effectiveness of your absorption trench and require complete replacement. A costly exercise.