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Understanding Soakaway Drainage System: A Comprehensive Guide

A soakaway drainage system is a simple yet highly effective method for managing surface water runoff, preventing flooding, and ensuring proper drainage in both residential and commercial properties. This guide will help you understand the basics of a soakaway drainage system, its benefits, installation process, and maintenance, ensuring you have all the information you need to make an informed decision about using this system for your drainage needs.

What is a Soakaway Drainage System?

A soakaway drainage system is an underground structure that allows rainwater and surface runoff to naturally percolate into the ground. It typically consists of a pit or trench filled with rubble or other coarse materials. The primary function of a soakaway is to manage excess water, ensuring it is absorbed into the surrounding soil rather than causing surface flooding or waterlogging.

How Does a Soakaway Drainage System Work?

The working principle of a soakaway drainage system is straightforward. When it rains, water collects on surfaces such as roofs, driveways, and patios. This water is channeled into the soakaway, where it slowly infiltrates the ground. The soakaway pit is filled with porous materials, which provide temporary storage for the water and allow it to seep into the soil at a controlled rate.

Benefits of a Soakaway Drainage System

  1. Flood Prevention: By managing excess surface water, soakaways prevent flooding in gardens, driveways, and other areas.
  2. Environmental Protection: Soakaways help reduce the burden on public drainage systems and minimize the risk of water pollution.
  3. Cost-Effective: Once installed, soakaways require minimal maintenance, making them a cost-effective long-term solution.
  4. Groundwater Recharge: By allowing water to percolate into the ground, soakaways help recharge groundwater levels, benefiting the local ecosystem.

Types of Soakaway Drainage Systems

There are several types of soakaway systems, each suited to different applications and soil conditions:

  1. Traditional Rubble-Filled Soakaways: These are the most common type, consisting of a pit filled with coarse stone or rubble. They are suitable for small-scale residential applications.
  2. Soakaway Crates: Made from plastic, these crates provide a more structured and efficient way to manage water runoff. They are ideal for larger projects and areas with poor soil drainage.
  3. Modular Geocellular Systems: These are advanced systems that can be customized to fit specific requirements. They offer high storage capacity and are suitable for both residential and commercial applications.

Installing a Soakaway Drainage System

Installing a soakaway drainage system involves several key steps:

  1. Site Assessment: Before installation, assess the site to determine the best location for the soakaway. Factors such as soil type, groundwater levels, and proximity to buildings must be considered.
  2. Excavation: Dig a pit or trench of the appropriate size and depth. The size of the soakaway will depend on the volume of water it needs to manage.
  3. Lining: Line the pit with a geotextile membrane to prevent soil particles from clogging the system.
  4. Filling: Fill the pit with coarse aggregate, such as gravel or rubble. If using soakaway crates or geocellular systems, assemble and place them according to the manufacturer’s instructions.
  5. Connection: Connect the soakaway to the drainage system, ensuring water flows efficiently into the pit.
  6. Backfilling: Cover the soakaway with a layer of topsoil and turf or other suitable surface material.

Maintenance of a Soakaway Drainage System

Soakaway systems are relatively low-maintenance, but periodic checks are essential to ensure they function effectively:

  1. Inspect Regularly: Check the soakaway and surrounding area for signs of waterlogging or flooding, indicating a potential blockage.
  2. Clear Debris: Ensure that gutters and downpipes feeding into the soakaway are clear of leaves, debris, and other obstructions.
  3. Monitor Performance: After heavy rain, observe how quickly water drains away. Slow drainage may indicate a need for maintenance or repair.
  4. Professional Inspection: Consider having a professional inspect the system periodically, especially if you notice persistent drainage issues.

Common Issues and Solutions

  1. Clogging: Over time, sediment and debris can clog the soakaway, reducing its efficiency. Regular cleaning of gutters and downpipes can help prevent this issue.
  2. Poor Soil Drainage: In areas with clay or other poorly draining soils, a soakaway may struggle to disperse water effectively. Using soakaway crates or modular systems can help improve performance.
  3. Incorrect Installation: Improperly installed soakaways can lead to flooding and waterlogging. Ensure the system is installed by a professional to avoid these issues.

Cost of Installing a Soakaway Drainage System

The cost of installing a soakaway drainage system varies depending on several factors:

  1. Size and Type: Larger and more complex systems, such as geocellular systems, are more expensive than traditional rubble-filled soakaways.
  2. Soil Conditions: Poor soil conditions may require additional work, such as soil replacement or the use of more advanced systems, increasing costs.
  3. Labor and Materials: Professional installation costs and the price of materials also influence the overall cost.

On average, a simple residential soakaway system can cost between £500 and £1,500, while larger, more complex systems for commercial properties can cost several thousand pounds.

Planning and Regulatory Considerations

Before installing a soakaway drainage system, it’s essential to consider planning and regulatory requirements:

  1. Building Regulations: In many areas, installing a soakaway may require adherence to specific building regulations. Check with your local authority for guidelines.
  2. Permits: Depending on the location and scale of the project, you may need planning permission or permits. Ensure all necessary approvals are obtained before proceeding.
  3. Environmental Impact: Consider the potential environmental impact of the soakaway. Ensure it does not adversely affect local watercourses or groundwater supplies.

DIY vs. Professional Installation

While it’s possible to install a simple soakaway system yourself, hiring a professional offers several advantages:

  1. Expertise: Professionals have the knowledge and experience to assess site conditions, design an effective system, and ensure proper installation.
  2. Quality Assurance: Professional installation reduces the risk of issues such as incorrect sizing, improper placement, and inadequate materials.
  3. Compliance: Professionals are familiar with local regulations and can ensure your system complies with all relevant requirements.

Enhancing Your Soakaway System

To further enhance the effectiveness and longevity of your soakaway drainage system, consider the following tips:

  1. Use a Rainwater Harvesting System: By collecting and reusing rainwater, you can reduce the volume of water entering the soakaway, extending its lifespan.
  2. Implement Sustainable Urban Drainage Systems (SUDS): SUDS techniques, such as permeable paving and green roofs, can help manage surface water runoff more effectively.
  3. Regular Maintenance: Keep your soakaway system in top condition with regular inspections and maintenance.

Case Studies

Here are a few examples of successful soakaway installations:

  1. Residential Property: A homeowner in a flood-prone area installed a soakaway system to manage roof runoff. The system effectively prevented garden flooding and reduced pressure on the local drainage system.
  2. Commercial Building: A commercial property with extensive hard surfaces used a modular geocellular system to manage stormwater. The system successfully prevented surface water accumulation and complied with local regulations.
  3. Public Park: A public park incorporated multiple soakaway systems to manage rainwater from pathways and open spaces. This approach enhanced the park’s usability and prevented waterlogging.

Future Trends in Soakaway Drainage Systems

As environmental concerns and urbanization increase, the demand for effective drainage solutions like soakaways is likely to grow. Future trends may include:

  1. Advanced Materials: The use of innovative materials, such as recycled plastics and biodegradable options, could improve the sustainability of soakaway systems.
  2. Smart Technology: Integration with smart water management systems could enable real-time monitoring and optimization of soakaway performance.
  3. Green Infrastructure: Combining soakaways with other green infrastructure elements, such as rain gardens and bioswales, could create more resilient and sustainable urban environments.


A soakaway drainage system is a practical, cost-effective solution for managing surface water runoff, preventing flooding, and enhancing groundwater recharge. Whether for a residential property, commercial building, or public space, understanding the basics of soakaway systems, their benefits, installation, and maintenance can help you make an informed decision and ensure effective water management.

For a quote or professional assistance with installing a soakaway drainage system, contact VIV Construct Group.