A soakaway is a system designed to manage surface water drainage by allowing excess rainwater to gradually infiltrate back into the ground, reducing the risk of flooding.
Traditionally, soakaways were simple pits filled with rubble that facilitated slow drainage into the surrounding soil. Today, modern soakaways utilise eco-friendly plastic crates that can store more water and are environmentally friendly.
These systems are also frequently employed to divert rainwater from gutters and wastewater from septic tanks, often found in gardens or other outdoor areas.
Advantages and Disadvantages of a Soakaway
Advantages:
- Soakaways require minimal space.
- They contribute to groundwater recharge.
- Offer good volume reduction for excess water.
- Simple to construct and maintain.
- Help reduce pressure on overloaded main drainage systems.
- Visually aesthetic – no manhole access making them invisible to landscapes.
Disadvantages:
- Not suitable for soils with poor drainage.
- Susceptible to blockages from dirt and leaves – silt filters can help prevent this.
- If not installed at a sufficient distance from property or it isn’t draining correctly, they may impact home foundations.
- Ineffective in areas with poor-draining soil.
Soakaway Installation
If you feel confident, installing a soakaway can be straightforward. However, a percolation test is essential before installation to assess how well the soil drains. Poor soil porosity, such as in clay or clay-based soils, can cause the soakaway to fail, making it ineffective for infiltration.
Be sure to check and comply with local building and planning regulations before starting any work.
1. Pick Your Spot and Assemble the Soakaway Crates
Select a spot for the soakaway, ensuring it's a safe distance from your property to protect the foundations. Most crates easily lock together, and you can use cable ties for extra sturdiness.
2. Dig the Pit
Dig a pit slightly larger than the soakaway crates, allowing space for the base, backfill, and sidefill. A sand or gravel base of around 150mm is recommended. Keep the sides and bottom of the pit as straight and square as possible.
3. Dig a drainpipe trench
Dig a trench from your rainwater pipes to the soakaway pit to direct water flow.
4. Fill Your Pit and Install the Soakaway
Layer 150mm of sand or gravel at the bottom of the pit. Wrap the soakaway crate in a geotextile membrane, covering all outward-facing surfaces and the pipe entry point. Locate the membrane-covered pipe entry, mark the centre, and carefully cut a cross with a utility knife. Insert the drainpipe about 15cm through the cut.
5. Backfill and Surface the Area
Backfill around the soakaway, with about 150-350mm along the sides and 300-500mm on top. Smooth the soil surface with a rake to finish.
Soakaway Maintenance
Regular maintenance of a soakaway is essential to prevent blockages that could harm the surrounding land and potentially impact property foundations.
are an effective way to prevent unwanted buildup and can be performed by specialists without excavation. While silt traps help keep debris out, they should also be inspected regularly to ensure proper water flow. Keeping nearby trees and vegetation trimmed can further protect the soakaway by preventing debris from entering the soakaway and roots from overgrowing.
Soakaways generally need replacement every 10 years, though proper care can extend their lifespan up to 15 years. A poorly functioning soakaway risks costly damage to gardens and property alike.
Expert Drainage Advice
Contact Hydro Cleansing for all your drainage needs and questions! With 25 years of experience, our team of drainage experts is here to provide the advice and support you need—just give us a call.
