Soakaways: Frequently Asked Questions

September 22, 2020

We get a lot of questions about soakaways, from how deep they need to be to simply, what are they? So in this months blog, we are here to shed some light on those frequently answered questions and hopefully help our clients, new and old out!

Do I need a soakaway?

UK Building Regulations require you to adequately dispose of rainwater from your building. This includes using guttering and pipes to direct the excess water away from your own, and other properties. Generally, rainwater will just seep away into either drain or through the soil. However, depending on the type of ground or lack of drainage, you might require a soakaway to help the water disperse into the ground evenly and quickly. It is often difficult to know yourself if you need a soakaway, but contacting an expert in rural drainage will answer that question in no time!

How does a soakaway work?

A soakaway works by encouraging rainwater to flow quickly through the soil into a hole or pit created. Traditionally, a soakaway is just a large hole, lined with rubble. However, an increasingly popular soakaway solution is soakaway crates. These are large plastic that helps to control the rate at which the water filters through the soakaway.

How deep should a soakaway be?

The general rule for calculating the depth of a soakaway is 1 cubic metre of a soakaway for 30 sqm of the roof. This is measured below the pipe invert so you’ generally dig 1.3m deep and 1m x 1m. Soakaways can be installed by anyone, but there are a lot of regulations to follow to ensure they are fit for purpose, so it is always best to get an expert involved from the early planning stages to ensure you are not left with damp issues or improper drainage.

Can a soakaway get blocked?

The main problem people experience with soakaways is that they can become blocked up with silt, leaves and debris. These foreign bodies are washed into the soakaway and can therefore prevent the rainwater from being collected and percolated back into the soil.  Often is it difficult to notice a blockage, but over time standing water will increase on the land.

Often a blockage can be cleared with high-pressure water jets, this should only be done by a professional in the know!

What is a soakaway?

Soakaways are designed as a solution to aid standing surface water issues. They consist of a large hole or pit that collects surface water from a drainage pipe and supports the water flow to slowly percolate the water through the soil. A soakaways purpose is, therefore, to reduce the risk of flooding and improving the stability of the ground.

Before creating a soakaway, it is recommended that a percolation test is carried out. This is a test to determine the absorption ability of the soil, and whether water will pass through.

For more questions, please contact the expect drainage team at Croft Drainage on 01427 671255 or email them on