Septic Soakaway System Advice, Tank and Drainage Design and Installation

Septic Tank Soakaway Systems and Drainage Fields - How they work 

A septic tank soakaway system performs two functions:-
  • It uses naturally occuring aerobic soil bacteria to further clean the pollutants in the effluent
  • It disperses septic effluent into the soil

The Environment Agency has confirmed to us that DEEP BOREHOLE soakaway drilling as a method of solving drainfield issues is NOT generally acceptable to them.  BEWARE of such adverts on the Internet!

The size of the soakaway system or drainage field will be dependant on the following factors,

1. The porosity of the soil.

2. The size of the property (based on the number of bedrooms) and the number of residents it serves.

Proper modern septic tank system soakaways are constructed with long trenches filled with a clean washed stone, fed by solid perforated drainage pipe. These trenches are interconnected and have a design similar to an oven grid tray.

However, older septic tank drainfields sometimes did not have to conform to any Building Regulations and may be a simple A failed septic tank soakaway pitlong trench, a herringbone drainage layout or a large stone filled pit.  All these latter types are often not fit for the purpose as percolation tests were not carried out and they are frequently inadequate.

All soakaways have a limited lifespan which is made shorter if the correct emptying and maintenance of the septic tank is ignored.  If you do not empty your tank on a regular basis the suspended solids from the tank will be forced down the drains and into the soakaway, clogging the pipes and contaminating the soil with a black, slimy biomatt, making the drainfield no longer effective.

When this happens, the septic tank soakaway system comes to the end of its life and a new drainfield must be installed.  Tell-tale signs that this is happening are when your tank fills to a level above that of the outlet pipe, especially after heavy rainfall.   If the water in the septic tank rises then it is probable the drainage in the drainfield is damaged.

Rules and Regulations for Septic and Foul Drainage soakaways

Minimum distances that the drainfield should be from:
  • Buildings - 15 metres
  • Boundaries - 2 metres
  • Water abstraction point (well, spring, borehole) - 50 metres
  • Watercourse (ditch, stream, river) - 10 metres
  • No access roads, driveways, paths, buildings, etc. should be within the drainfield area.  If it is in a field, then tractors are not allowed to drive over it.
  • No water or electric cable or pipes should be within the drainfield area.
  • The bedrock or water table should not, at any time, be within 1.2 metres of the drainfield pipework.

If you have a question about your septic tank soakaway give us a call on 01757 288022 and we can normally arrange a free survey and diagnosis of the extent of the soakaway system problem.

Tank Installers Wanted
Crystal is currently seeking installers for  sewage plant and septic tanks which DO have the EN12566-3 throughout many parts of the UK.
Latest News
Consent to Discharge axed under the EPP2 regs. You now apply for a Discharge Permit or exemption for septic tank and sewage systems online free of charge.
OASIS Rainwater Harvesters

We also build our own OASIS Rainwater Harvesting Systems

Contact Us
 
The Byre
Foggathorpe
SELBY
YO8 6PX
Tel. 01757 288022
or 01757 289423
Email
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British Water Members

Please telephone us on 01757 288022 as sewage treatment enquiries are too complex for email correspondence

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