Drainage Upgrades in Warriewood
Chris Smith • May 6, 2026
Aggy Line Installation & Stormwater Improvements
When Holly in Warriewood
on Sydney’s Northern Beaches engaged Eze-Flow to address ongoing drainage issues around her property, the backyard had been experiencing constant water pooling and flooding in the backyard during heavy rain.
Holly initially described the issue as a “very wet portion of the backyard”, suspecting additional aggy lines may be required.
With new paving planned, there were concerns that without proper drainage, heavy rainfall would result in water flowing back toward the house. It was clear the existing stormwater system was not coping and required upgrading before any surface works could proceed.
The works were completed in two stages across November 2025 and March 2026, delivering a complete drainage solution across the property.
The Problem
- Water pooling in the backyard, particularly along the right-hand side of the property
- No existing subsoil drainage in the lawn to manage groundwater
- Existing stormwater pits were undersized and ineffective, providing little to no drainage
- Inadequate stormwater system unable to handle water volume during heavy rain
- Risk of water flowing back toward the house once paving was installed
- Behind the retaining wall, previously installed aggy lines were defective, silted up, and incorrectly installed directly into the soil
These combined issues meant the system was not managing water effectively, resulting in ongoing flooding during heavy rain and increasing the risk of water impacting the property.
Eze-Flow Plumbing's Solution
A staged approach was taken to resolve the drainage issues and ensure the system could effectively manage both surface water and groundwater, using Eze-Flow's proven drainage and stormwater solutions
tailored to Holly's property.
In November 2025, initial works focused on addressing the immediate pooling and flooding issues in the backyard and preparing the site ahead of paving.
The bases of two front downpipes were cut out and rebuilt using new PVC pipework, along with installation of a screwed inspection opening for future access.
Excavation was then carried out in the backyard to the right-hand side of the property, within the grassed area, where twin subsoil aggy lines were installed along the retaining wall, terminating into the existing stormwater pit. These lines were installed approximately 600mm apart, wrapped in geotextile fabric, and backfilled with blue metal aggregate to ensure effective filtration and drainage. The total length of the installation was approximately 27 metres.
These works provided immediate improvement, capturing surface and groundwater and relieving the pooling issues across the yard, while ensuring the area was properly drained ahead of paving.
As part of the overall plan, further works were scheduled to address drainage behind the retaining wall once access became available.
Drainage solutions are a long-term investment in protecting your home and preventing costly damage. While they can involve significant work, Eze-Flow works closely with clients to plan projects in stages where required, allowing immediate improvements while giving clients time to budget and see the results of each stage as the system is progressively upgraded.
In March 2026, after the client had excavated behind the retaining wall, Eze-Flow returned to complete the next stage of works.
Further works were carried out on the left-hand side of the house, where the existing stormwater pit and pump system were found to be undersized and ineffective.
The existing pit and pump were removed, and excavation was carried out to locate the main stormwater line. A new connection was made into the stormwater system, allowing water to discharge via gravity directly to the street. This removed reliance on the pump system and significantly improved the overall performance and reliability of the drainage system.
The downpipe was reconnected into the upgraded system, and the previous pump discharge line was capped off.
At the same time, the previously installed aggy drainage behind the retaining wall was found to be ineffective, having been incorrectly installed directly into the soil and completely silted up.
This section was reworked by installing twin 65mm aggy lines along an 11-metre section, backfilled with drainage aggregate and wrapped in geotextile fabric to prevent future silting. These new lines were connected into the existing aggy system installed during Stage 1, creating a continuous drainage network across the property. Installing twin aggy lines provided greater flow capacity compared to a single larger pipe, allowing more effective capture and discharge of water while reducing pressure build-up behind the retaining wall.
Additional upgrades included replacing damaged stormwater pits to ensure the system could handle increased water flow effectively.
All works were completed, connected into the existing system, and reinstated on completion, leaving the area clean, level, and ready for paving.
Following completion of the works:
- Water is effectively captured and redirected across the property
- Pooling and flooding issues during heavy rain have been eliminated
- Retaining wall drainage has been properly installed and is now functioning correctly
- Stormwater system upgraded to discharge via gravity, removing reliance on the pump
- Twin aggy line system provides increased drainage capacity
- Stormwater pits and system upgrades have improved overall reliability
The property now benefits from a reliable, long-term drainage solution designed to manage water effectively, even during heavy rainfall, allowing Holly and her family to get back to enjoying their backyard.
If you're dealing with poor drainage, water pooling, or flooding during heavy rain, Eze-Flow can help.
View our stormwater solutions across the Northern Beaches or contact Eze-Flow today for reliable drainage services.
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When a Primary School in Forestville began experiencing extensive stormwater blockages and localised flooding in May 2025, the issue was initially believed to be a simple blockage. Eze-Flow was called in to clear the stormwater system , however after attending site and beginning high-pressure water jetting to clear the multiple lines, it quickly became clear the problem was more complex. Grates were removed from multiple stormwater pits and heavy debris was manually cleared, including built-up soil, tree roots, and rubbish. One of the main pits was completely filled with compacted soil and roots, requiring excavation by hand before the outlet could be cleared. Using high-pressure jetting and CCTV drain inspections, we attempted to cleared both upstream and downstream. During this process, a significant amount of debris was removed, including food wrappers, chip packets, and multiple balls lodged throughout the pipeline. After approximately two hours of continuous jetting, two sections were identified as requiring excavation and repair. CCTV inspection confirmed a collapsed section of pipe, while another section was found to be obstructed by a foreign pipe that had been incorrectly installed into the stormwater line.
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