French drains can be useful where shallow groundwater or subsurface flow needs to be intercepted, but they are not suitable for every wet-ground or building-moisture issue. This guide explains how they work, when a French drain is the right solution, and what you should expect to pay for professional drainage installation in 2026.
What does a French drain cost in Auckland?
French drain installation
- Basic residential French drain (perforated pipe, aggregate, geotextile): $120 - $180 per lineal metre installed
- Deep French drain or high water table installation: $180 - $280 per lineal metre
Drain outlets
- Outlet to kerb or soakpit: $400 - $900 per outlet depending on distance and connection type
Associated works - allow separately
- Surface reinstatement (lawn, path)
- Council connection fees if applicable
These are Auckland market ranges for 2026. Your actual cost depends on the factors below.
What drives the cost of a French drain?
- 01
Drain depth and length
Deeper drains in high water table conditions require more excavation and machine time. Depth should follow the water source, levels and outlet.
- 02
Soil and ground conditions
Auckland clay holds water and is slow to excavate. Sandy or gravelly soils are faster. Ground conditions are the biggest variable in French drain pricing.
- 03
Outlet location
The drain needs somewhere to discharge. A kerb outlet, soakpit, or council stormwater connection each has different costs. A soakpit is often the most cost-effective option on sections with adequate permeability.
- 04
Access
Machine access along the drain line reduces cost significantly. Hand-dig only situations (tight sections, established gardens, under decks) are slower and more expensive.
- 05
Geotextile and aggregate specification
Quality geotextile wrapping and clean aggregate prevent the drain from silting up. Cutting corners here means the drain fails within a few years.
- 06
Licensed drainlayer requirement
French-drain installation itself may involve groundwater collection that falls outside restricted drainlaying, but connection into regulated stormwater drainage or other restricted drainage work may require an appropriately licensed drainlayer and the relevant network approval. Bromley Group has licensed drainlayers in the business.
When do you need a French drain?
- Water pooling on your lawn after rain that doesn't clear within 24-48 hours
- Soggy or waterlogged areas on the section that never fully dry out
- Water tracking along a boundary or retaining wall
- Damp or water ingress at the base of a retaining wall or boundary wall where groundwater or surface water is the cause
- A sloping site where surface water runs toward the house
What should be in a French drain quote?
- Drain length, depth, and profile (perforated pipe diameter, aggregate type, geotextile spec)
- Outlet type and location - soakpit, kerb, or council stormwater connection
- Whether surface reinstatement is included (lawn, path, paving)
- Council connection fees if applicable
- Licensed drainlayer details - name and licence number
Watch out for:contractors who don't use geotextile wrapping or who substitute clean aggregate with crusher dust. Both cause premature silting. Ask to see the spec before you agree to a price.
How to get an accurate quote
- Photos or video of the problem area after rain
- Section dimensions and approximate drain route
- Whether you have an existing outlet or need one created
- Any known ground conditions - previous work, tree roots, high water table
Bromley Group installs French drains across Auckland residential and commercial sites. Our Auckland drainage team includes our licensed drainlayers. For wider drainage pricing, see our drainage cost guide. Discuss Your Project.