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01 JAN

French drains and septic tanks by-laws

Written by Drain Ratz Plumbing Posted in Sewage Treatment Solutions

What are the french drain and septic tank municipal by laws?

Before installing any underground features like sewerage lines or even septic tanks or french drain systems, always call your local Municipality First!

Once you have received the proper permit for your septic tank and french drain/soak away, we are good to go. If unsure about the rules and regulations of septic tanks and french drains/soak aways, Drain Ratz Plumbers & Builders are just a call away.

As a general policy the municipality is only prepared to permit the installation of a french drain/soak away when the soil conditions are ideal.  The municipality reserves the right to insist on the removal of a septic tank and french drain/soak away at any time in their sole discretion.


  1. Size of plot must be considered. (900 square metres)

  2. The soil must be suitable for the installation of a french drain/soak away. In more than one case the municipality has allowed for the installation of a septic tank but not a french drain/soak away. If this is a case, the most long term cost effective solution would be to install a treatment plant. Drain Ratz Plumbers & Builderswould be able to assist you as they are leaders in this field.

  3. There must be a stable water source.

  4. The septic tank and french drain/soak away if feeding a dual or single pipe line must be excavated 2 to 3m away from the building it services.

  5. The inlet and the outlet must be accessible from the inspection covers in the top of the tank.

  6. The Director of Health Services may condone a combined drainage system depending on the absorption capacity.

  7. Most important rule: septic tanks must be watertight.

  8. Most sites are comfortably fitted with durable plastic tanks and it is recorded that the precast concrete and the everite asbestos cement tanks have been approved by the municipality and may be permitted in certain circumstances but not in conjunction with a combined drainage system.

  9. When a sewerage system is installed, all buildings must be connected to the sewer, septic tanks and french drains/soak away closed down.

    New rules for septic tanks and french drains 

(Old fashioned way of just digging a hole and filling it with building rubble and stones – Not permitted, according to the new rules and regulations.) Follow these below and you will be safely on your way of having an approved unit.

  1. A trench-style french drain/soak away with walls of cement blocks,hollow tile brickwork and cavities to be in tile horizontal plane.

  2. Standard size: 600 mm x 600 mm x 7 5mm paving slabs. The trench must have a surround of stone/half burned bricks and width must be 450 mm and to the full depts. Of the walls. Should your permit, stipulate differently, implement that which is stated on your permit.

  3. Should have a system of agricultural drainpipes guided by the circumstances, not less than 3 metres from any building or boundry.

  4. Pit: should be round constructed with cement blocks or hollow clay tiles with cavities in the horizontal plane. The pit size should be 2 metres in diameter and dept as circumstances indicate. The pit should have reinforced slab over the top to contain a 600 mm x 150 mm inspection cover.

  5. Most important factor: it must be parallel to the contours of the ground.

  6. The length of the french drain/soak away must be determined in relation to the soil and general site conditions and the number of appliances seved by the french drain/soak away.

Low lying ground

If you have a low lying ground with a high water table, the municipality may allow the round/circular soakage pit Subject To Terms & Conditions.

  1. The level of the site around the french drain/soak away to be considered. It must be raised above the level attained by storm water.

  2. Use a channelling system like gutters, down pipes to carry all roof water away from the french drain/soak away to the nearest road.

  3. Buildings must be damp proof at least 2 courses above the level of the filling.

  4. French drain/soak away must be an adequate size, the depth being dependent upon the summer water table in any particular area.

  5. There must be a clearance level of at least 25rnrn between the invert level of the final discharge pipe into the french drain/soak away and the maximum water table in the french drain/soak away pit.

  6. In cases where your french drain/soak away is not functioning properly, and you have an arrangement with the municipality for the removal of wastewater, a watertight sump may be permitted in placer of, or in addition to a french drain/soak away.the watertight sump should be able to capacitate 4500lites, it must be properly ventilated and situated not more than 12 metres from a vehicular approach to permit of future servicing which will be the responsibility of the owner.

For a job like this, it is always wise to contact the professionals and here at Drain Ratz Plumbers & Builders . We are always willing to assist, whether it is a New installation or a simple repair!


01 JAN

Septic tank installation

Written by Drain Ratz Plumbing Posted in Sewage Treatment Solutions

How to install a septic tank: 

A septic tank should always be connected to french drain unless of course you are installing a digestor. There is a difference in the installation process.This easy DIY installation guide is only for the septic tank installation. There are also 2 types of pipelines to consider and this installation only covers a septic tank on a single pipe line.How to install a french drain is more complicated and will soon follow on the next seriess of articles for Dummies.

Easy DIY Installation. Get ready to go all in and get dirty.

Installation on a single pipe line:

Hole: Excavation of the correct size of hole is key to the installation of a septic tank. The general rule to follow for a single installation is: 2m long, 1.8m wide and 1.2 deep.  The excavation should be 3m to 4m away from the building. Some septic tanks are also round so you should first look at the diameters of the round tank in order to work out he calculations of the hole. Always leave enough room in the hole  so that you may be ale to work comfortably. Remember that the septic tank will need to be compacted so you need to leave enough room in the hole for compacting purposes.You can make use of tlb’s or manual labour, whichever is cheaper for you.

Golden Tip – Always look for sandy type soil for excavation for installations requiring french drain installations as rocky ground is difficult for excavation. Make sure that no solids are protruding from the cement sand mix. Once you have decided on your excavation site, you may continue wit step 2.

Placing the septic tank into hole: Get a friend to help

Materials needed: 1.6 river and cement mix – this is to be measured for 300mm across the base of the excavated hole.  (in other words:  this should be enough to cover the 300mm base of excavated hole).
3 pvc pipes (should be enough), 3 kimberley sockets, 3 bends and material for backfilling which is generally cement and soil. Purchasing an extra bag of cement if necessary.  Should you prefer to go further away from the house, the piping, parts etc also increases.Make sure that when you insert the septic tank into the hole that it is levelled and bedded correctly..

Tools needed: wrench, pvc glue for joining of the pipes (most important),sand paper to clean joints, water pump to do chipping of corners if needed and a spirit level to keep pipes straight, plumbers soft soap.

Ramming of the pvc pipes: You would need a soap and water solutions. If you have difficulty in fitting a pipe into another pipe, you would have to ram it.

Connecting the septic tank: Find the septic tank inlet:  Find the septic tank toilet outlet. These are usually on the side of the septic tank. On the top you have your breather and the lid of the septic tank (leave these two alone for now). Connect the toilet outlet with a 110mm pvc pipe to the septic tank inlet. Your septic tank outlet is connected to our french drain inlet if you have the necessary permit for a french drain installation.

How does one connect a grease trap for dual pipe line: One should have a grease trap installed on a dual water line, (the water from the bath and the shower called the grey water line). This line is connected to the inlet of the fat trap and the outlet is going to the french drain.

Backfilling: The application of filling the hole once the connection is complete. This is done to stabilise the tank.

Process for backfilling: 1.6 concrete sand mix should be carried out in 300mm thick layers from the base up to 100mm below the top of the septic tank hole with the concrete filled lid in place on the hole. The backfilling material must be slightly moist. This is important. Each 300mm should be densely compacted. This will allow your filling around the tank not to sink. For deeper manholes or where a high water table is anticipated, the backfill mix must be 5% cement and 95% sand or selected granular material.

Please note: Dual Pipe Lines: the application is the same, it is only the connection of the grease trap that differs.

If all else fails, you can always rely on Drain Ratz Plumbers & Builders (sewerage specialists), to come and install it professionally for you

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