Marine Desalination Systems & Offshore Water Treatment
ForeverPure builds marine desalination systems for vessels and offshore platforms: skid-mounted seawater reverse osmosis watermakers (often called fresh water makers or offshore water makers) from 200 to 2,000 gallons per day, shipped from our Santa Clara, California facility with current prices published below, and containerized seawater desalination plants from 7,200 to 800,000 GPD for platforms, FPSOs and island supply. Every system is engineered for the corrosive saltwater environment and for consistent, high-quality potable water far from shore.
Marine Applications
- Commercial vessels — Cargo ships, tankers, fishing boats, and ferries
- Offshore platforms — Oil rigs, wind farm service vessels, and floating production units
- Naval and coast guard — Military ships, patrol boats, and support vessels
- Cruise ships and yachts — Passenger vessels requiring high-volume potable water
- Island supply vessels — Emergency water delivery to remote island communities
System Capabilities
Our marine SWRO systems are available from 200 GPD watermakers for small vessels up to 800,000 GPD systems for large offshore installations. All marine systems feature:
- 316L stainless steel and duplex stainless steel frames rated for marine environments
- Corrosion-resistant FRP membrane vessels and non-metallic piping
- Compact footprint designed for engine rooms and machinery spaces
- Energy recovery devices for fuel savings at sea
- Auto-flush and chemical-free preservation for intermittent use
- Remote monitoring via satellite for technical support while underway
Vessel-Scale Watermakers: Capacity, Power and Current Prices
For vessels and smaller platforms, these skid-mounted seawater RO watermakers ship ready to install. The 200 and 500 GPD units share a Danfoss APP high-pressure pump and run on DC or AC power; the 1,000 and 2,000 GPD units step up to 220 V single-phase supply and standard 4″×40″ seawater membrane elements. Prices below are the current selling prices and link to each product page, so a sale or price change is visible rather than silently stale.
| System | Fresh water per day | Power | Current price | Typical use |
|---|---|---|---|---|
| 200 GPD Watermaker | 200 gal (757 L) | 12/24 V DC or 110/230 V AC | $9,822.60 | Fishing boats, patrol craft, small crew vessels |
| 500 GPD Watermaker | 500 gal (1,893 L) | DC or AC | $12,183.05 | Mid-size commercial vessels, yachts, ferries |
| 1,000 GPD Watermaker | 1,000 gal (3,785 L) | 220 V single-phase, about 1.5 kW | $14,166.95 | Larger crews, offshore support, island supply |
| 2,000 GPD Watermaker | 2,000 gal (7,570 L) | 220 V single-phase, about 2 kW | $16,291.95 | Crew boats, small platforms, expedition yachts |
Rated outputs are at 60 Hz with warm feed water. The 1,000 and 2,000 GPD units produce 800 and 1,600 GPD at 50 Hz, and membrane output falls roughly 3% per °C below the 25 °C rating point, so a unit working in cold northern water makes on the order of 60–70% of nameplate — choose the next size up. Solar-hybrid versions of the three smaller capacities — the Solar Oasis 200, Solar Oasis 500 and Solar Oasis 1000 — are built for remote stations and low-fuel operation; contact us for configuration and lead time.
Sizing a Watermaker for Your Vessel
Start from daily demand: a water-conscious working crew uses 10–20 gallons per person per day, a commercial vessel with laundry 25–40, and a yacht or passenger vessel 50–100 or more, plus deck wash-down, engine-room make-up and any ice or hold wash. Then size on runtime, not on demand: required rated capacity = daily demand ÷ target runtime hours × 24. A unit whose rating equals daily demand would have to run around the clock with no margin for fouling, cold water or a fault; sizing to an 8–10 hour window lets it run only while the generator is already loaded.
| Vessel and complement | Allowance | Daily demand | Recommended unit | Runtime at rated output |
|---|---|---|---|---|
| Fishing boat or patrol craft, 4 crew | 20 gal/person | 80 gal | 200 GPD | about 9.6 h/day |
| Workboat or small commercial vessel, 8 crew | 25 gal/person | 200 gal | 500 GPD | about 9.6 h/day |
| Commercial vessel with laundry, 12 crew | 30 gal/person | 360 gal | 1,000 GPD | about 8.6 h/day |
| Offshore crew or supply boat, 20 persons | 30 gal/person | 600 gal | 2,000 GPD | about 7.2 h/day |
| Charter yacht, 8 guests and 4 crew | 60 gal/person | 720 gal | 2,000 GPD | about 8.6 h/day |
| Platform, FPSO or island supply, 40+ persons | 30–100 gal/person | 1,200+ gal | Containerized, 7,200 GPD and up | continuous duty |
Send us crew or passenger count, target runtime, available power and the coldest water you expect to work in and our engineers will size the system — or work through the full calculation, including the power budget and recovery at sea, in ForeverPure Corporation’s marine watermaker sizing guide.
Offshore Platform Solutions
Offshore platforms require water treatment systems that operate reliably in remote, harsh conditions with minimal maintenance. ForeverPure containerized desalination systems are ideal for platform deployment—they arrive fully assembled in standard ISO containers and can be crane-lifted into position. Integrated pre-treatment handles the variable water quality typical of open-ocean intake. Standard containerized units start at 7,200 GPD and 10,085 GPD, and larger plants add an energy recovery device that cuts specific energy from the 8–15 kWh/m³ of a small watermaker to about 3–5 kWh/m³.
Potable Water Disinfection Offshore
Seawater RO permeate leaves the membrane below 500 ppm TDS and essentially free of bacteria and viruses, but potable tanks on a vessel or platform are warm and stagnant, and stored water can regrow. Offshore water sterilization is therefore a second step after desalination, not a substitute for it: the WHO Guide to Ship Sanitation calls for potable water to carry a disinfectant residual, and the usual arrangement is a UV sterilizer at the tank outlet sized to the distribution flow, with chlorination where a residual in the tank itself is required. UV adds no chemicals and no taste and suits an unattended platform; chlorination needs dosing and residual monitoring but protects the water all the way to the tap.
Why Marine Operators Choose ForeverPure
- Marine-certified components — Built to withstand saltwater environments
- Compact containerized designs — Maximize use of limited ship/platform space
- Global spare parts shipping — Replacement membranes and consumables shipped worldwide
- Remote monitoring — Satellite-connected systems allow shore-based technical support
- Custom engineering — Systems designed to fit your vessel's specific space and power constraints
Need a marine watermaker or offshore water treatment system? Request a quote or call +1-408-969-2688.
Beyond standard systems: for custom-engineered marine and offshore watermakers built to your vessel or platform specification, visit our engineering division at ForeverPure Corporation: Seawater Desalination Systems. Their guide to energy recovery in SWRO explains how ERDs cut the fuel cost of making water at sea, and their marine watermaker sizing guide covers daily demand, runtime, the power budget and cold-water derating in depth.
Marine Watermaker FAQ
What size watermaker does my vessel need?
Work out daily demand from crew or passenger count (10–20 gallons per person per day for a water-conscious working crew, 25–40 with laundry, 50–100 or more on yachts and passenger vessels), then divide by the hours you want the unit to run and scale to 24: required capacity = daily demand ÷ runtime hours × 24. An 8-person crew at 25 gallons each needs 200 gallons a day; at an 8-hour target runtime that calls for about 600 GPD of rated capacity, which is a 500 GPD unit running about 10 hours a day or a 1,000 GPD unit running about 5. The sizing table above and ForeverPure Corporation’s marine watermaker sizing guide go through the calculation in full.
How much does a marine watermaker cost?
ForeverPure’s skid-mounted seawater watermakers currently sell at $9,822.60 for 200 GPD, $12,183.05 for 500 GPD, $14,166.95 for 1,000 GPD and $16,291.95 for 2,000 GPD, with the current price shown on each product page and linked from the table above. Containerized systems from 7,200 GPD upward are quoted to specification.
What power does a marine watermaker need?
The 200 and 500 GPD units run on DC or AC power — the 200 GPD on 12/24 V DC or 110/230 V AC — so they work from a battery bank, solar array, generator or shore power. The 1,000 GPD unit draws about 1.5 kW at its 900 psi working pressure on 220 V single-phase, 50 or 60 Hz, and the 2,000 GPD unit about 2 kW, feed pump excluded. Small watermakers without energy recovery use roughly 8–15 kWh per cubic meter of fresh water; on larger systems an energy recovery device brings that to about 3–5 kWh/m³.
Can I run a watermaker in a harbor or marina?
No. Fuel and oil sheen in harbor water fouls RO membranes irreversibly and no practical shipboard pretreatment removes hydrocarbons. Make water offshore in clean open water, keep the intake away from engine cooling discharge, and watch salinity in estuaries and river plumes.
How do I protect a watermaker between voyages?
Flush the membranes with fresh water after every run so seawater does not sit in the pressure vessels — an automatic flush on shutdown removes the step a tired crew skips — and use a chemical preservative for any lay-up longer than about a week to stop biological growth. Replacement prefilters and seawater membrane elements are in the membranes and filters section.
Is watermaker output safe to drink?
Yes — the permeate is drinking-quality water below 500 ppm TDS, monitored by the built-in TDS meter on the 1,000 and 2,000 GPD units. Because stored water can regrow in a warm tank, potable systems on vessels and platforms add a disinfection step: a UV sterilizer at the tank outlet or a maintained chlorine residual in the tank.