Oasis Soakwells
Soakwell Installation in Perth
When it rains hard in Perth, the water off your roof, paving and driveway has to go somewhere. Your soakwells are what decide whether that’s back into the ground where it falls, or sitting against your footings. Getting an installation right means the volume your property actually produces, positioned the correct distance from the house, and set at a depth that holds up under whatever goes back over the top.
We’re Oasis Soakwells, a family business installing soakwells across the Perth metropolitan area since 2016, from Yanchep down to Mandurah. Every new installation is backed by a 25-year guarantee on workmanship and materials.
Below you’ll find what’s included in an installation and what you can add, how we install soakwells, where they can and can’t go on your property, and what affects soakwell installation costs in Perth. Whether you’re building, adding a patio, or dealing with a soakwell that’s stopped draining, this is where to start.
Soakwell Installation Quotes
We quote the whole job, not just the hole in the ground.
What’s Included in Your Soakwell Installation
Geotextile fabric on every unit
Each soakwell is wrapped so the surrounding sand can’t wash in and clog it, while water still drains away freely.
Sizing calculated for your property
Councils publish stormwater recommendations based on storm event data. We use that data alongside your soil type and catchment area to work out what your property genuinely needs, rather than defaulting to the formula and leaving it there.
25-year guarantee
Our 25-year guarantee covers our workmanship and materials.
Water compaction and plate compaction
This is the step that protects everything you put on top afterwards. Backfill that isn’t compacted properly leaves air pockets underground. Those pockets fill with water over the following winters, the soil around the soakwell sinks, and the paving or concrete above sinks with it.
Perth’s soil types vary across the metro area and each behaves differently, so knowing how to prepare the ground for what’s going over it is the difference between paving that stays level and paving that doesn’t. If you’re investing in concrete or paving after your installation, this is where that investment is protected.
Additional Services You Can Add
Two services we offer alongside the installation, charged separately so you can take them or leave them.
Soil removal
Excess soil from the excavation leaves with us, so you’re not filling a skip bin on the weekend.
Paving and artificial grass reinstatement
We lift your pavers or artificial grass to get access, then we can put them back the way we found them.
Costs That Can Apply
Cutting concrete, where it’s needed to create an installation area, is an additional cost, and concrete isn’t able to be reinstated by us.
A hard-ground surcharge applies if we hit limestone or clay once digging starts. We’ll talk you through the cost before we go ahead rather than adding it to the invoice afterwards.
How We Install Soakwells
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Get in touch with us
Tell us about your roof, where your downpipes sit, what’s already in the ground and what you’re trying to fix, and we’ll give you a figure to work from. If there’s uncertainty on your side or ours after that, we may arrange a site visit.
Either way, you’ll have possible costs outlined before we start on installation day.
Soakwell work deals with what’s hidden underground: service lines, old soakwells and septic tanks, buried paving, old concrete footings. A site visit often can’t show us those. So rather than promise a number we might have to revise, we tell you upfront what could be down there and what each scenario would cost.
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We dig by hand
Wherever we can, the soakwell hole is dug with shovels rather than bringing a machine in. It’s the old-school approach, and it means no risk of damage to underground service lines. It also lets us work in spaces a machine can’t reach, and it disturbs a smaller area of your property.
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We get the depth right
A soakwell’s strength comes from what sits above it. The more cover over the top, the stronger the system. Trafficable areas, where vehicles will drive over the soakwell, need 500mm of cover. Non-trafficable areas need 200mm to 300mm. Depth isn’t only about fitting the unit in, it’s what makes the system capable of carrying whatever goes over it.
Direct Connections vs Grated Downpipes
We don’t recommend piping a downpipe with a direct connection straight into a soakwell. It’s a dated method, and if the system ever reaches capacity, stormwater can back up the downpipe and damage your eaves, gutters and roof space.
Instead, we fit a grate beneath each downpipe so water falls in at ground level before being directed into the soakwell. If the system is ever overwhelmed in heavy rainfall, you get water pooling on the ground rather than water in your roof. Water on the lawn is a far smaller problem than water in the roof space.
There’s one exception. Under a patio or another covered area, water can flush across the top of a grate and wet the space you’re trying to keep dry. There we may recommend an adaptor instead, provided it’s part of a connected system with a grate elsewhere, so the water still has an external escape. It’s a call our team will talk through with you on the day if it applies to your property.
How Many Soakwells Do You Need?
It starts with your total impermeable catchment area: roof area, plus paving, driveways and any other surface that sheds water instead of absorbing it. The capacity your property needs is what dictates how many soakwells go in and what size they should be, rather than being a separate choice.
The Council Formula
Most Perth councils publish the same starting point: roof area (m²) × 0.0125 = required volume (m³), which works out to roughly 2.5m³ for a 200m² roof.
That figure is a guide rather than a strict requirement, and it often comes out larger than a property actually needs. We assess your real soil type and catchment area and give you an honest recommendation on what’s required versus what’s a conservative buffer. If your property needs more than the council minimum to hold up long term, we’ll tell you that too and lay out the options.
Where Soakwells Can Go on Your Property
Site access
Restricted access is rarely a limiting factor for us. Confined spaces and restricted access installations are one of our specialities, and as land sizes shrink across Perth, they’re becoming the norm rather than the exception. Narrow side gates, courtyards and tight side setbacks are all workable with the right unit and the right approach. There’s a solution for almost every residential property.
Clearance from the house
As a rule of thumb, a soakwell needs at least as much clearance from your structural footings as the hole is deep. Boundary setbacks are a separate requirement set by your local council. We confirm both distances for your property before we dig.
Underground services
Power, water, gas, reticulation and comms all need locating and working around, which is exactly why we hand dig rather than bringing a machine in.
Distance from the downpipe
Where the best install point sits well away from your downpipe, the trade-off is the length of plumbing needed to reach it. That affects the price rather than whether the job can be done.
Soakwell Installation Costs in Perth: What Affects Your Quote
Every property is different, so soakwell installation cost in Perth comes down to site-specific factors rather than a flat rate.
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Roof and catchment area
Sets the capacity your property needs, which sets the number and size of soakwells. This is the biggest single factor.
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Length of plumbing
Reaching an accessible install point from your downpipe is often the real cost driver. Longer runs add cost.
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Soil type and depth of dig
Sandy soils are generally faster and more straightforward to work with. Clay and limestone areas take longer.
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Concrete cutting
Where concrete needs cutting to create space for the soakwell, that’s an additional cost.
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Additional services
Soil removal and reinstating your pavers or artificial grass are charged separately, so you can include them or handle them yourself.
You’ll get a clear quote before we start. If we hit limestone or clay once we’re digging, a hard-ground surcharge applies, and we’ll always talk you through that.
Polypropylene or Concrete Soakwells?
We supply and install both, and we’ll talk you through the trade-offs for your site rather than leave you guessing. Soil type is one of the first things we check on any property.
For most Perth properties, polypropylene soakwells are our expert recommendation. They’re hand-dug, lightweight and trafficable, with commercial-grade strength comparable to concrete, they interlock permanently once installed, and they can be configured to suit the volume your catchment area calls for. With no machinery required, they typically cost less than concrete.
Concrete soakwells are heavier and well proven, and still the right call on some sites. They suit new builds particularly well, where installation happens at slab stage and access isn’t a constraint. They do need machinery, which means more disruption to your property and makes site access a bigger factor.
Installations We Take On
New homes
The best time to install soakwells is at slab stage, while access is clear and there’s no paving or landscaping to work around. Talk to us early. If you need the whole system planned from scratch, that’s our residential stormwater drainage system design service.
Patios, granny flats and extensions
Any new roof area adds to your catchment area and usually needs its own capacity.
Pools
We relocate and reinstall soakwells displaced by pool installations, and install and manage soakwells for pool backwash systems.
Replacements
Water pooling on your lawn or driveway after heavy rainfall usually means the existing soakwell is undersized, blocked or has failed. If a repair is the better answer, see soakwell repairs. If the lid or grate is the visible issue, see soakwell lid and grate replacement.
Strata and commercial sites
The same council requirements apply, at a larger scale. If you’re managing a strata property or a commercial site, we’ll work around your tenants, customers and operating hours, and keep the site tidy while the work is underway.
Channel Grate Installation
Where your property slopes, a channel grate installation often works alongside your soakwells to stop stormwater in its tracks and redirect it into the soakwell. These are commonly installed across the front of a garage or shed to protect what’s stored inside.
Not sure if our soakwell installation services cover what you’re after? Give our team a call and we can walk you through our recommendations and advise how we can help.
Frequently Asked Questions
There’s no flat rate, because the cost is driven by your property rather than by a price list. The main factors are the capacity your roof and catchment area call for, which sets how many soakwells you need and what size, and the length of plumbing needed to reach an accessible install point from your downpipe. Soil type matters too, since sandy ground digs quickly while clay and limestone take longer. Concrete cutting, where it’s needed to create an installation area, is an additional cost, as is a hard-ground surcharge if we hit limestone or clay once we start digging. We’ll talk you through that before going ahead rather than after. Every installation includes our 25-year guarantee, while soil removal and reinstating your pavers or artificial grass are optional extras, charged separately. Get in touch and we’ll give you a figure to work from, with every possible cost outlined before installation day.
There’s no single required depth. It’s set by the size of the unit going in and by your ground conditions, with the soakwell sitting below finished surface level so it can be paved or turfed over. The depth of the dig matters for more than the hole itself, because it determines how far the soakwell has to sit from your house: the clearance from your structural footings should be at least as much as the hole is deep. That means going deeper isn’t automatically better, and the right depth is the one that suits your soil, your available space and the volume your property needs. We work that out on site before we dig.
As a rule of thumb, we keep at least as much clearance from your structural footings as the hole is deep, so a 1.2 metre deep soakwell needs roughly 1.2 metres of clearance. The reason is straightforward. A soakwell discharging water too close to your footings saturates the ground your house sits on, and in Perth’s sandy soil that can wash sand out from under the footings, leading to cracking, moisture issues and rising damp. Boundary setbacks are a separate requirement set by your local council. We confirm both distances for your property before we dig.
For most Perth properties, yes, and it’s our expert recommendation. Polypropylene soakwells are hand dug, so there’s no risk of damage to underground service lines, and only a small area of your property is disturbed during installation. They’re commercial-grade strength comparable to concrete, they interlock permanently once installed, they’re trafficable and commonly used under driveways and paved areas, and they can be configured to suit the volume your catchment area needs. With no machinery required, they typically cost less. Concrete soakwells still have their place. They’re heavier and well proven, and they suit new builds where installation happens at slab stage and access isn’t a constraint. They do need machinery, which means more disruption to your property and makes site access a bigger factor. Soil type is one of the first things we check, and we’ll confirm what’s right for your site before you decide.
Start with the council formula most Perth councils publish: roof area (m²) × 0.0125 = required volume (m³). A 200m² roof works out at roughly 2.5m³. Then account for any other impermeable surfaces feeding into the system, such as paving and driveways, since they shed water rather than absorbing it. That total volume is what determines how many soakwells you need and what size they should be. Worth knowing the council figure is a guide rather than a strict requirement, and it often comes out larger than a property actually needs. We assess your real soil type and catchment area and give you an honest recommendation on what’s required versus what’s a conservative buffer.