What is a Rainwater Soakaway?

Here at ASL Drainage, we install soakaways and drainage fields in domestic and commercial areas throughout the UK. This article aims to tell you everything you need to know about soakaways so you can make an informed decision. To find out more about draiange fields, click here. There are two varieties of soakaway, a rainwater soakaway and a septic tank drainage field, read on to find out more.

What is a Rainwater Soakaway?

A rainwater soakaway is ideal for wet climates as it is designed specifically to drain excess rainwater, otherwise known as runoff. Rainwater soakaways are most commonly used in rural areas where storm drains have not been provided and residents do not have access to a suitable public sewer or watercourse. If you live in a wet climate, a rainwater soakaway is a must to avoid waterlogging and flooding.

How Does a Rainwater Soakaway Work?

A rainwater soakaway removes excess levels of water from your garden. Quite simply, it is a hole in the ground that is filled with rubble that allows water runoff to slowly drain and redistribute itself into the soil.

Rainwater soakaways tend to deal with large volumes of water and are generally reinforced with concrete chambers and perforated on the bottom to help allow the water to escape effectively. The size of a rainwater soakaway is dependent on several factors, including the size of the property, number of occupants and the ease with which water drains through the soil.

Rainwater Soakaway Construction

The construction of a rainwater soakaway is reasonably simple. It has a low environmental impact and is the ideal solution to drainage because it uses very few materials.

Rainwater soakaways must be installed at least five metres from the external walls of your property, on soft turf, to allow the excess water to drain. It is best to aim for a lower area of your garden as this helps ensure the water will run towards the soakaway, effectively draining and preventing waterlogging of your lawn.

Rainwater Soakaway Regulations

The building regulations regarding rainwater soakaways are strict and often unadhered to. The building regulations are quite prescriptive in their demands as to how rainwater should be appropriately handled. For more information, we would advise you read the Building Regulation Approved Document H to understand the full specifications for rainwater soakaways.

Do it Yourself

If you would like to build your own rainwater soakaway system, the smaller your rainwater soakaway needs are, the more likely you will be able to successfully do it yourself. However, you must consider the following:

  • You must establish whether your site is a Groundwater Source Protection Zone.
  • You should dig a Trial Site Assessment Hole to find out whether the bedrock or water table ever comes within one metre of the rainwater soakaways pipe bottom or not. Numerous sites in the UK commonly fail this test.
  • You must carry out a percolation test to ensure the excess rainwater will dissipate into the soil at an acceptable rate.

Points to Remember

  • When installing your rainwater soakaway, it must be located 5 metres from the external property walls and must not encroach within 2 ½ metres of next doors fence.
  • The stone or other filling materials must completely surround the pipe and come to at least 100mm above it, with another layer placed on top. This top layer might be a tarpaulin or a layer of topsoil but it must be added.

Rainwater Soakaway Maintenance

A rainwater soakaway should not require any maintenance. However, it is a good idea to lift the cover and check the soakaway for signs of silting (where the soakaway has become blocked). If silting occurs regularly, it may be worth constructing a catch pit to intercept the silt before it reaches the soakaway. Alternatively, you could manually remove any silt during dry conditions when the soakaway is empty.

When soakaways are old, they can sometimes cease to function. This is usually because the structure has become frequently blocked with silts and muds that are causing problems with the soakaway functionality. The most effective method, in this case, is to re-build the structure from scratch.

Contact us Today

If you have any questions or specific enquiries regarding rainwater soakaways and the design, regulations, suitability to your property, or anything else, our team here at ASL Drainage are available to offer professional advice. So, call us today and let us advice you on the best cause of action for your property.

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