How Much Does a Seawater Desalination Plant Cost?

A seawater desalination plant is priced mainly by production capacity and configuration rather than by physical size alone. As an industry reference, a 5 t/h plant producing about 120 tons of fresh water per day is quoted in the range of CNY 400,000-800,000, while a 10 t/h plant producing about 240 tons per day runs CNY 700,000-1,300,000 — including equipment, installation and commissioning but excluding civil works, which corresponds very roughly to USD 55,000-110,000 and USD 95,000-180,000 respectively. This guide explains what actually drives the number and how to compare supplier quotes fairly.

What Determines the Price of a Desalination Plant

Capacity comes first. A 10 t/h system carries more RO membranes, a larger high-pressure pump and a bigger energy recovery device, so it typically costs about 1.5-2 times a 5 t/h plant. Feed water quality is second: coasts with high turbidity or heavy sand loads need extra dissolved air flotation or ultrafiltration pretreatment. Membrane brand also matters, as imported premium membranes cost noticeably more than domestic ones. Finally, PLC full-automatic control with remote monitoring and stronger corrosion protection for salty island air both raise the price — and both are usually worth paying for over a 20-year plant life.

Reference Price by Capacity

A 5 t/h SWRO desalination plant (about 120 m³ per day) sits in the CNY 400,000-800,000 band, and a 10 t/h plant (about 240 m³ per day) in the CNY 700,000-1,300,000 band. For a typical project, equipment procurement makes up 60-70% of the total investment, civil and intake/outfall engineering adds 10-20%, transport plus installation and commissioning 10-15%, and first spares, membranes, training and design the remaining 5-10%. Containerized desalination plants keep the civil share low, because the whole system arrives factory-assembled, test-run and ready to produce water within 1-3 months of site handover.

Running Costs: Electricity Is the Biggest Item

Once operating, the total cost of water is about CNY 4-8 per ton. Electricity is 55-65% of that figure: a modern plant with energy recovery consumes only 3-4 kWh per m³, and without an energy recovery device consumption rises to 4-6 kWh per m³. Membrane and cartridge replacement, based on a membrane life of 2-5 years, accounts for 15-20% of the operating cost; chemicals such as antiscalant and cleaning agents about 5-10%; and labor plus routine maintenance 10-15%.

A Cost Example You Can Calculate

Take a 10 t/h plant delivering 240 tons per day at an average cost of CNY 5 per ton. The daily operating cost is about CNY 1,200, or roughly CNY 430,000 per year. At an electricity price of CNY 0.6 per kWh, power alone costs CNY 160,000-210,000 each year — which is why an energy recovery device that saves about 30% of high-pressure pump energy usually pays for itself quickly. Recovery rate also matters: at a typical 40-50%, it decides both the seawater intake volume and the brine to be discharged. Per liter, the water works out to only CNY 0.004-0.008, a small fraction of bottled water and far cheaper than trucked water, which commonly costs tens of CNY per ton on islands and remote coasts.

Why Choose WTEYA

WTEYA designs and builds skid-mounted and containerized desalination systems with nearly 20 years of water treatment experience, serving more than 2000 customers worldwide. Every system is factory assembled and test-run before shipment, product water is verified below 200 ppm TDS with over 99.5% salt rejection, and the company offers free technical consultation and scheme design, so the quotation you receive is based on your real water quality, electricity price and site conditions rather than a generic price list.

Frequently Asked Questions

Why do supplier quotes for the same capacity differ so much? The gap usually comes from scope. Check whether an energy recovery device is included, which membrane brand and how many elements, the automation level, the corrosion protection grade, and whether civil works, freight and commissioning are inside the quotation. Ask for an itemized offer covering the equipment list, civil scope, transport, installation and commissioning, and warranty.

How long does it take to build a seawater desalination plant? Containerized plants are typically producing water within 1-3 months because most of the system is assembled and tested in the factory. Civil works and intake/outfall engineering are usually the scheduling bottleneck for larger permanent plants.

Is desalinated water really cheaper than bottled water? At CNY 0.004-0.008 per liter — roughly one tenth of a US cent — desalinated water costs a tiny fraction of bottled water, and for islands and coastal facilities it is usually far more economical than water shipped in by truck.

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