What is a soakaway?
Basically it’s a pit dug out and filled with hard core (rubble or stones) into which waste water is piped with the idea that it drains out slowly into the surrounding soil. They are used as a drainage solution to waterlogged ground.
Soakaways are put in either by a garden business or a householder doing it themselves. However, Mole often get called out to look at a better garden drainage solution after a soakaway has been put in, as it hasn’t worked effectively. Why not? Because unfortunately soakaways don’t work in many parts of the UK.
Why don’t soakaways always work?
They can work if they are done properly in the right sort of ground conditions.
Usually French drains (trench filled with rubble) are run from the problem patch to a pit full of loose stones, people think water then soaks into ground hence, “soakaway”, but often it can hold the water like a pond. Maybe on a bigger area of land the soakaway can be well away from the problem area, maybe down a hill – but the area will get boggy. This is therefore not a solution as you still have an area that is mushy underfoot. Soakaways in solid clay won’t work as there is nowhere for water to soak out to (clay pots are watertight!)
What are the alternatives?
A garden drainage pump is a more logical and longer term solution because it extracts the water out of the garden and maintains a lower water table – around 1m below the table. The extracted filtered water (a membrane is put in to stop sand and stones) is pumped via an air gap into a gully at your house, maybe the one your rainwater from the roof goes into. Mole’s garden drainage system costs more than a simple soakaway as it is a more sophisticated system which is tailored to suit the individual case: factors need to be taken into account like types of soil, source of land lying water, elevation etc. Soakaways may be simple but they are not always effective.