Water bore drilling in the Perth Hills is very different from drilling a typical garden bore on the Swan Coastal Plain.
Much of the Perth Hills is underlain by ancient granite and other hard crystalline rocks. Groundwater is often associated with weathered rock and fractures within the harder bedrock.
As a result, bore depth, water yield and drilling conditions can vary considerably from one property to another.
Aquarian Drilling has been drilling water bores in Western Australia since 1994. We have extensive experience drilling the hard and variable ground conditions found throughout the Perth Hills, Darling Scarp and surrounding areas.
Why Is Water Bore Drilling Different in the Perth Hills?
Many Perth metropolitan bores are drilled through sand, sediment or limestone formations.
The Perth Hills are different.
Typical ground conditions can include:
Laterite
Clay
Weathered granite
Decomposed granite
Quartz
Dolerite
Hard granite
Fractured granite
These formations can change significantly with depth and location.
More importantly, groundwater in hard-rock areas is often associated with fractures, joints and weathered zones within the rock.
Therefore, finding granite does not necessarily mean finding water.
The bore needs to intersect a water-bearing formation or fracture capable of supplying groundwater.
Where Does Perth Hills Bore Water Come From?
In hard-rock areas, solid granite has very little primary porosity. In simple terms, groundwater does not usually move through solid granite in the same way it moves through sand.
Instead, water can collect and move through:
Weathered rock
Cracks and joints
Fractured granite
Geological contact zones
Other openings within the bedrock
These water-bearing features can be localised.
A productive fracture may pass beneath one property but not another. Even two bores relatively close together can produce very different results.
That is one of the main risks of drilling for groundwater in the Perth Hills.
Can You Guarantee Water in the Perth Hills?
No.
No responsible water bore driller can guarantee that a particular hole in fractured-rock country will produce a specific amount of water.
Nearby bore records, groundwater information, geology and local drilling experience can help assess a site. However, they cannot show exactly what will be encountered beneath a particular drilling location.
The actual result is only known once drilling begins.
Aquarian Drilling believes this risk should be explained clearly before a customer commits to drilling.
Does Drilling Deeper Guarantee More Water?
No. A deeper bore does not automatically produce more water.
The bore must intersect water-bearing geology.
For example, a bore may intersect a productive fracture at 30 metres, 50 metres or considerably deeper. Another hole may pass through a substantial depth of competent granite without finding a fracture capable of supplying the required flow.
Drilling deeper increases the opportunity to intersect additional fractures. However, depth alone cannot guarantee a successful result.
This is why experienced hard-rock drilling is about more than reaching a predetermined depth.
How Deep Are Water Bores in the Perth Hills?
There is no single standard depth for a Perth Hills water bore.
Required depth depends on factors such as:
Property location
Ground elevation
Depth of weathering
Local geology
Fracture locations
Static groundwater level
Water-bearing zones encountered during drilling
Required water yield
Nearby bore information can provide useful guidance. However, the depth of a neighbouring bore should never be treated as a guaranteed drilling depth for another property.
Why Can Bore Yields Vary Between Nearby Properties?
Fractured-rock groundwater can be highly variable.
One bore may intersect a productive fracture and provide a strong water supply.
Another bore nearby may produce a smaller but reliable flow.
A third hole may not produce enough water to justify installing a pump.
This does not necessarily mean that a lower-yielding bore is useless.
The important question is whether the bore can provide enough sustainable water for its intended purpose.
Can a Low-Yield Perth Hills Bore Still Be Useful?
Yes.
A low-yield bore can still provide a valuable water supply if the system is designed correctly.
For example, a bore producing a modest but reliable flow can progressively fill a storage tank.
A separate pressure pump can then supply the house, gardens, livestock troughs or irrigation system from the tank at a much higher instantaneous flow rate.
This approach allows the bore to operate closer to its natural recharge rate.
It can be a better solution than installing an oversized bore pump and attempting to extract groundwater faster than the bore can replenish it.
Why Pump Selection Matters
The biggest pump is not necessarily the best pump.
A submersible pump should be selected to suit the completed bore.
Important factors include:
Bore depth
Static water level
Pumping water level
Available bore yield
Recharge rate
Pump setting depth
Required flow
Required pressure
Pipe size
Distance to the point of use
Total pumping head
Installing a pump that exceeds the sustainable yield of a bore can cause excessive drawdown and poor system performance.
For lower-yield Perth Hills bores, a correctly selected submersible pump combined with tank storage can provide a practical solution.
What Drilling Equipment Is Used in the Perth Hills?
Perth Hills drilling often requires different equipment from shallow sand-bore drilling.
Once hard granite or similar formations are encountered, down-the-hole (DTH) hammer drilling may be required.
A DTH hammer uses compressed air to operate a hammer behind the drill bit. It is designed to penetrate hard-rock formations efficiently.
Aquarian Drilling has experience with both conventional formations and hard-rock drilling.
The drilling method can therefore be adapted to the geological conditions encountered.
Why Does Perth Hills Geology Affect Drilling Costs?
Not every metre of drilling is the same.
Drilling through softer weathered material is very different from drilling through hard granite.
Cost and drilling time can be affected by:
Bore depth
Hardness of the formation
Changes in geology
Casing requirements
Drilling method
Water entries
Bore construction
Development requirements
Site access
For this reason, comparing contractors purely on a price-per-metre basis may not provide a meaningful comparison.
The proposed drilling method, bore construction and capability of the equipment should also be considered.
What Is the Risk of a Dry Bore?
A dry or insufficiently productive bore is a genuine risk when drilling fractured-rock formations.
No amount of drilling experience can create a water-bearing fracture where one does not exist.
Experience does, however, help the driller assess the geology being encountered and make informed decisions during drilling.
This includes considering:
Changes in the formation
Fractures encountered
Water entries
Available flow
Is the flow improving
Whether further drilling is justified
Whether the bore is suitable for development and pump installation
Customers considering a Perth Hills bore should understand this geological risk before drilling starts.
Does Bore Location Matter?
Yes. Bore position can matter.
However, there is no surface feature that can guarantee groundwater at depth.
Where practical, we consider factors such as:
Property access
Local topography
Known geology
Nearby bore information
Existing drainage
Underground services
Buildings and structures
Trees
Overhead powerlines
Future access to the completed bore
The drilling rig must also be able to safely reach and operate at the proposed bore location.
This can be particularly important on steep, heavily vegetated or difficult Perth Hills properties.
What About Bore Water Quality?
Finding groundwater is only part of the result.
Water quality can also vary between locations and water-bearing formations.
Depending on the area, groundwater may contain different levels of:
Dissolved salts
Iron
Minerals
Sediment
Colour
Other naturally occurring dissolved material
Water quality should therefore be considered alongside bore yield.
A high-flow bore is not necessarily useful if the groundwater quality is unsuitable for its intended purpose.
Why Is Bore Development Important?
Drilling into water is not the end of the bore construction process.
The completed bore should be properly developed.
Bore development helps remove drilling debris and fine material from the water-producing zones. It also allows the bore’s performance to be assessed.
Depending on the geology and bore construction, development may include airlifting and other appropriate development methods.
The objective is to produce a clean and stable bore that makes the best practical use of the water-bearing formation encountered.
Why Hard-Rock Drilling Experience Matters
Perth Hills bore drilling involves decisions that often need to be made while the hole is being drilled.
An experienced driller needs to assess:
What formation is being drilled
Whether the geology is changing
Where water is entering the bore
Whether useful fractures have been encountered
Whether additional depth is justified
How the bore should be constructed
How it should be developed
Where the pump should be positioned
Whether the bore yield suits direct irrigation
Whether tank storage is a better solution
These decisions cannot be made from a standard depth chart alone.
They require practical drilling experience and an understanding of local geology.
Perth Hills Water Bore Specialists
Aquarian Drilling is a family-owned Western Australian water bore drilling and repair company established in 1994.
We provide water bore services across the Perth metropolitan area, Darling Scarp, Perth Hills and surrounding rural areas.
Our Perth Hills service areas include:
Gidgegannup
Stoneville
Mundaring
Mount Helena
Darlington
Swan View
Kalamunda
Walliston
Lesmurdie
Bickley
Pickering Brook
Roleystone
Chittering
Lower Chittering
Bindoon
and surrounding areas.
Our services include:
Water bore drilling
Hard-rock drilling
DTH hammer drilling
Bore construction
Bore development
Submersible pump installation
Pump replacement
Bore fault diagnosis
Electrical controls
Bore repairs
Low-yield bore solutions
Tank-fill systems
Bore and pump system assessment
Planning a Water Bore in the Perth Hills?
Before drilling, it is important to have realistic expectations about the geology and groundwater conditions.
Aquarian Drilling can assess the available information and discuss:
Likely geology
Expected drilling conditions
Likely bore depth
Property access
Hard-rock drilling requirements
Bore construction
Pump options
Low-yield bore solutions
Tank storage
Groundwater quality considerations
The risks associated with fractured-rock drilling
Our approach is straightforward.
We would rather explain the geological risks before drilling starts than promise a result that cannot be guaranteed underground.
For Perth Hills water bore drilling, hard-rock drilling, pump installation and bore repairs, contact Aquarian Drilling on 0417 928 330.
Frequently Asked Questions About Perth Hills Water Bores
Can you guarantee that a Perth Hills bore will find water?
No. Groundwater in the Perth Hills is often associated with weathered and fractured rock. The location and productivity of these fractures cannot be guaranteed before drilling.
Does drilling deeper always find more water?
No. Additional depth may increase the chance of intersecting another water-bearing fracture, but drilling deeper does not guarantee additional groundwater.
Why are Perth Hills bores different from Perth sand bores?
Many coastal plain bores obtain groundwater from porous sand, sediment or limestone formations. Perth Hills bores often rely on groundwater stored and transmitted through weathered and fractured hard rock.
What happens if my bore only produces a small amount of water?
A lower-yielding bore may still be useful. It can slowly fill a storage tank, with a separate pressure pump supplying irrigation or other water requirements from the tank.
What drilling method is used for granite?
Hard granite is commonly drilled using compressed-air DTH hammer drilling. The appropriate drilling method depends on the formations encountered.
How deep will my Perth Hills bore need to be?
There is no standard depth. Bore depth depends on the local geology, groundwater conditions, elevation and water-bearing fractures encountered during drilling.
Can a neighbouring bore tell you how deep mine will be?
Nearby bore information is useful, but it cannot guarantee the result on another property. Fractured-rock groundwater conditions can change over relatively short distances.
Is a high-yield bore always better?
Not necessarily. Sustainable yield and water quality are more important than a high initial flow. The pump and water system should be designed around what the bore can sustainably supply.
Do you drill throughout the Perth Hills?
Yes. Aquarian Drilling services the Perth Hills, Darling Scarp and surrounding areas, including Gidgegannup, Stoneville, Mundaring, Mount Helena, Kalamunda, Walliston, Lesmurdie, Bickley, Pickering Brook, Roleystone and nearby districts.