Septic tank FUNCTION Checklist

Septic tank checklist starts with these DIY tasks:-

The reality is we need to do a lot ourselves post-pandemic. As you know the limited number of tradies will not have time to do the digging. Last time, nearly 2 years ago in a very hot February, as Australia opened up to the tail-end pandemic; a man diagnosed with dyslexia plus autism  and the 60yo woman owner builder did it all 🙂 Very proud of each other.

Photos included so you can see how we did it 🙂

The easiest ways that I would first try to estimate the location of where the blockage is: –

from shower outlet drain; are: –

  1. Time shower flow, then just stand there filling/emptying 10L buckets for the same time and tap ROTATION amount.
  2. Calculate volume, by multiplying number of buckets x 10L down drain till water collects a bit on drain “grate”
  3. Using the volume and the 40mm diameter of the pipe which is the standard size for shower drain pipes, calculate the length of pipe which would accomodate that volume by using the right formula of the 3 to choose from at
  4.  To cross-reference/double check measurement method in No.1; bring in a cleaned off hose by pulling it through a cloth as you bring it inside. Get a 10L bucket and fill it up with the hose [calling out to the other person standing by the back [new gold] garden tap to turn the hose on and off at a good pressure. Fill the bucket up very quickly and pour it down the drain hole as fast as you can
  5. Double brick walls are 250mm wide including cavity between inner and outer walls. Total it, any inside wall to shower drain centre with up to 100mm to pipe elbow outside the building, once you’ve dug it up.
  6. If blockage is further away from shower drain than the distance to outside elbow plus across to a vertical drop to sump, plus another 500mm to join the horizontal 100mm sewerage pipe from kitchen to septic tank – you can then measure the ‘X’ mm remainder calculated from volume, then dig up the pipe where you’ve calculated the blockage to be 🙂

    shower drain pipe to sump
    shower drain pipe to sump
  7. Don’t ask me how I dreamed up all this method – I put it down to ‘Inspirations’.  Heres a SKETCH -good ol’ paper and pencil 🙂
  8. 🙂 If you’ve estimated the blockage location, you can start digging by the sump hole, after reading below, especially A-D Basic Principles 🙂.
    1. New pipes only replaced old until the sump – problem could be there with more roots growing in to block it.
    1. Move tables etc down to garden edge under big trees to keep digging toward sump from bathroom and laundry.
    2. Of course if you’ve estimated the blockage location, you can start at this end by the sump hole. New pipes only replaced old until the sump – problem could be there with more roots growing in to block it. But you can see potential for the same problem  nearest the septic tank also.  CONSULT TEAM LEADER once you have found anything that looks like the problem.

😊 What we did in February 2022 =all digging and inspections

The basic principles are:-

A. Photograph where there are the really good paving bricks [usually where we walk most- to have the smoothest path] – between back tap to vegetable garden log’s corner [closest to flat bedroom door].

septic tank
Redundant Pipe from Previous Gutter system – Cutoff to Show Sewer Join to Septic 20220211


B. Carefully stack the bricks next to the position that they came from but a good 2-3 metres away this time [best on unpaved earth], not on paving where

C. piles of sand, and  clay should go on separate heaps  See photo – bricks didn’t leave enough space for sand

D. Don’t put bad bricks mixed up with good bricks in the stacks; so that when it comes to repaving àthe stacks will be all consistent

This detail is setting out the steps for people who have never done this before 🙂

How to dig up septic tank plastic pipes

Remove 8 rows of bricks as in photo and  set out as above A-D between base of garden log, but not from under it. It doesn’t budge then 😊Start from garden corner towards back tap…. About 2m long and 8 rows across

If near sump isn’t the problem, Next step is to start by SEPTIC TANK

  1. dig the sand layer off, toss it on a heap on far side of the brick paving, so a heap of clay can be piled between sand heaps and the brick paving edge. Remember width of paver removal is 8 rows because the trench gets a bit wide sometimes. At least it’s much softer with damp soil – than  February after summer!
  2. Trench  starts about a brick’s width away from brick paving row that’s  left under the log. Trench stays as narrow as needed to easily move curved edge shovel to dig, because you can see here where the pipe goes.
  3. at edge of septic tank, dig down for pipes which are less than 300mm below surface -Take Care  for raised PLASTIC ‘inspection caps’ along pipes, 1st very close to tank!! approx next to garden corner near a/c.  Only want pipe heading straight toward ‘back tap’ about 20cm from house wall there.
  4. Problem could be there with more roots growing in to block it! Common in garden system problems.
  5. After root removal – You could either
    • pipe connector
      black rubber 100m pipe joiners with screw collars

      wrap the pipe in a large sheet of hole-free plastic sheets with many layers each with edges Duct-taped to clean dry white pipe or 

    • several fine-wire loops secured very tightly like clamps,or
    • you could use 100mm screw-tightened  fastening rings like in left pic

      Inspection cap left one nearest to garden corner near a/c



  1. Might have to replace that section of pipe if fits inspection cap test shows flow impediment 🙁
  2. dig from where the inlet into the septic tank toward the back tap till you get to the first inspection cap
    • Then get a spare green hose on the back “gold tank water” tap and do a flow test = a slow amount of water to see if it drains away into the septic tank freely and in a timely manner proportionate to the flow from the hose.
    • this will indicate if the problem is anything to do with the tanks once and for all
    • If it flows OK, then you need to dig toward the tap to the next inspection cap – do the same test

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