What does an industrial water-treatment plant cost to build?
A worked breakdown from a real Design Dossier built by Anvil — an industrial water-handling, purification and fertigation plant supplying a large indoor cultivation facility.
Where the money goes
Water purification
Reverse osmosis, ultrafiltration, granular-activated-carbon and softening trains
£175,000
Controls & instrumentation
SCADA / process-control system plus plant-wide field instrumentation and cabling
£239,000
Storage & tanks
Galvanised process and buffer tanks with level instrumentation
£77,000
Process equipment, dosing & distribution
Fertigation dosing, flood-and-drain (ebb/flow) distribution, pumps, pipework, drain-water recovery and the hand-watering ring main
≈ £870,000
Total installed
≈ £1.36M
Excludes the grow-lighting, climate/HVAC hardware, cultivation racking and the building — supplied by others and out of scope for the water plant.
How the number is built — and how to check it
This isn't a rule-of-thumb. Anvil builds each Design Dossier from open engineering libraries and real component prices. Every figure traces through a live Excel model:
Fractional Forge does not review the workbook. Your own engineers should check it. Download the sanitised example and change an assumption to watch the costs recompute.
What drives the cost
Two things dominate. First, controls and instrumentation — a proper SCADA system with plant-wide sensing is often underestimated, and here it's the single largest line. Second, the purification train: how clean the water has to be, and how many treatment steps that takes, moves the number more than almost anything else.
Because the plant is modular — built from repeated skids, tanks and pumps — capital scales close to linearly. That makes it de-riskable: you can prove a small version and replicate it, rather than betting on one big monolithic build.
Common questions
How much does an industrial water-treatment plant cost to build?
For this worked example — a water-handling, purification and fertigation plant supplying a large indoor cultivation facility — the installed cost is around £1.36 million. The single biggest cost centres are the controls and instrumentation (~£239k) and the purification train (~£175k). Your figure depends on flow rate, water quality, the treatment steps you need and how much of the plant is duplicated for resilience.
What's included in that number?
The full water system: purification (reverse osmosis, ultrafiltration, activated-carbon and softening), storage and tanks, the fertigation dosing, the ebb/flow distribution network, drain-water recovery, a hand-watering ring main, pumps and pipework, and the SCADA/process-control system with plant-wide instrumentation. It excludes the grow-lighting, the climate/HVAC hardware, the cultivation racking and the building — those are supplied by others and out of scope.
How accurate are these numbers?
They come from a real Design Dossier built by Anvil — a live Excel workbook where every number is a traceable formula, from the inputs and assumptions through the calculations and quantities to the costed bill of materials and financial model. It has not been reviewed by Fractional Forge or an external engineer, so your own engineers should check it. The figures are indicative and specific to this plant, not a universal price. You can download the workbook and check every figure yourself.
Can I see the full model?
Yes. The complete, sanitised example workbook is free to download below — open it and change an assumption (flow, energy price, project life) to watch the costs and the financial model recompute.
Costing something you want to build?
Describe your idea in a short brief. Anvil delivers a buildable Design Dossier in a few days, including engineering drawings, worked calculations, a costed bill of materials, a financial model and a risk and regulatory register. It costs £2,500 per Dossier, or £6,000 a month for up to three.
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