Your Trusted Partner in Accurate Stormwater Estimating
Stormwater Estimates
When pipe sizes get larger, trench widths grow, bedding volumes increase, and so does the complexity of your stormwater project. If you’re not calculating each element correctly from the start, your budget can quickly spiral out of control.
Stormwater infrastructure isn’t just another excavation and pipe-laying job—it involves dealing with unpredictable ground conditions, deep trenches, heavy-duty materials, and tight construction programs. Whether you’re pricing a subdivision stormwater system or a large-scale catchment project, getting the estimate right is critical to your profit margins.
✅ Why Accurate Stormwater Estimating Matters for You
When estimating a stormwater job, there’s a lot that needs to go right—especially when it comes to:
🔍 1. Pipe Sizing and Depths
Larger catchment areas mean larger RCP or HDPE pipes
Long pipe runs are broken down into stormwater lines
Each line is made up of multiple chainages, based on design levels and slope
Problem: Misjudging chainage depths or trench volumes can lead to massive cost overruns.
Solution: We calculate each chainage precisely using the long section drawings, ensuring accurate excavation, bedding, and backfill quantities.
📏 2. Bedding & Overlay Material – Not Just an Afterthought
Wider trenches = more bedding
Bigger pipes like 600mm+ need greater bedding width and thickness
Bedding type and compaction class impact your price significantly
Problem: Estimating bedding volume incorrectly can wipe out your profit.
Solution: We factor in trench widths, pipe diameter, and compaction requirements to ensure nothing is missed in your bedding or overlay allowances.
🏗️ 3. The Right Machine for the Job
A 600mm RCP run at depth? You’ll need more than a 5T machine.
The choice of excavator must suit pipe size, depth, ground conditions, and required speed.
30T excavators are often a smart choice for efficiency and reach.
Problem: Underestimating machine size slows the job and inflates hire costs.
Solution: We match your machine size to the actual job requirement, so your site remains productive and cost-effective.
🕳️ 4. Pits & Pit Risers – The Hidden Stormwater Cost
Every line has multiple pits, each with a designated depth and class
You’ll receive a pit schedule, but turning that into accurate costing isn’t easy
Pit depth = multiple pit risers, and the higher the pit, the more risers needed
Bigger jobs require Class D pits and grates, which are significantly more expensive
Problem: Many contractors underestimate the number of risers or forget to allow for the correct pit class.
Solution: We analyze your pit schedule in detail, calculate riser requirements precisely, and include the correct pit classes so you don’t get hit with surprises.
⛏️ 5. RCP Pipe Cutting – Time-Consuming & Costly
RCP pipes often need cutting on-site to meet exact chainage lengths
Cutting is slow, labour-intensive, and requires skilled operators
Costs increase with pipe size and wall thickness
Problem: This is often forgotten during estimating—but shows up later as real labour time and cost.
Solution: We include realistic allowances for RCP cutting, especially on larger diameter pipes.
🪨 6. Backfill Material – A Major Cost Driver
Excavated material can’t always be reused, especially in roadways or poor soils
Select imported fill is often mandatory
Volumes can be underestimated if trench shape, width, and depth aren’t calculated accurately
Problem: Not accounting for backfill correctly can leave you paying out of pocket for truckloads of material.
Solution: We calculate precise trench volumes, check backfill requirements, and apply real-world compaction bulking factors.
💡 What You Get With Our Stormwater Estimating Service
When you need clarity on stormwater project costs, we help you by delivering:
✔️ Line-by-line breakdown of pipe runs using long section drawings
✔️ Accurate pit schedules with calculated riser and class costs
✔️ Correct machinery selection based on pipe size, depth, and trench width
✔️ Realistic bedding and backfill volume calculations
✔️ Time allowances for cutting, jointing, and installation
✔️ Inclusion of Class D covers, grates, and specialty fittings where required
✅ Save Time. Avoid Blowouts. Price With Confidence.
When you submit your stormwater estimate, you need to be confident that every detail is captured. The more complex the job, the more crucial this becomes.
Let us handle the heavy lifting of estimating, so you can focus on planning, winning the job, and delivering it profitably.
📩 Ready to quote your next stormwater job with confidence?
Send us your tender drawings and we’ll take care of the rest.