A yacht watermaker should not be run routinely in a harbour. Enclosed marina water presents a higher contamination risk than open water, and contaminants at the seawater intake can damage pumps, load prefilters and permanently harm membranes.
This guide explains which feed-water conditions to reject, how contamination affects the system, what to consider before running a watermaker around Mallorca, and when abnormal pressure, production or product quality requires technical attention.
Why harbour water is poor watermaker feed
Spectra's Ventura manual draws a clear distinction between open water and enclosed harbours. Spectra says harbours commonly contain more suspended solids than offshore water, while its Ventura manual warns that regularly operating in an enclosed marina or harbour carries a much higher risk of harmful feed-water contamination.
Suspended material is only part of the problem. Spectra's Ventura guidance says to keep petroleum products, chlorine-treated dock water, silty water, putrid or red-tide water, and visibly contaminated marina water out of the seawater intake. EchoTec likewise instructs operators not to use contaminated feed sources containing oil, chlorine or other chemicals.
The immediate concern is what the feed pump draws into the system. Spectra says silt can damage pumps and membranes. Oil is particularly serious because oil in feed water can permanently damage the membrane.
An oil/water separator may provide another stage of protection. Spectra recommends one if water must be made in harbours or polluted areas, while HRO uses a replaceable oil/water separator as a prefiltration component on its Seafari system. This does not make visibly polluted harbour water an acceptable feed source.
| Feed-water condition | Possible system effect | Crew action |
|---|---|---|
| Silt or heavy turbidity | Pump and membrane damage | Do not run the watermaker |
| Oil or fuel sheen | Permanent membrane damage | Keep the intake closed and call an engineer if drawn in |
| Chlorine or chemicals | Contaminated feed circuit | Reject the feed source |
| Fertile near-shore water | Plugged filters, lower output and pressure changes | Monitor readings and inspect prefilters |
| Putrid or red-tide water | Biological contamination and filter decay | Do not use it as feed water |
What harbour contamination does to the system
Poor feed water usually reaches the prefiltration stages before the membrane, but that does not mean the membrane is protected from every contaminant. A prefilter that looks acceptable cannot prove that the water is free from oil, chlorine or other chemicals.
Spectra says biologically fertile near-shore water can plug filters rapidly. As the filters load, water production and quality can fall, while system pressure can change dramatically. The useful comparison is therefore not a single gauge reading, but the relationship between pressure, output and salinity before and after near-shore operation.
A foul or rotten-egg smell from the product water is another warning. Spectra links this smell to decaying plankton and bacteria in the filters and directs the operator to stop and inspect the prefilters.
HRO's troubleshooting guidance also connects a low-pressure or vacuum symptom with the intake and prefiltration circuit. Its checks include screens, prefilters and the replaceable oil/water separator element. The exact components fitted aboard should be checked against the yacht's watermaker manual rather than assumed from another model.
If output falls or salinity rises without known contamination, the checks in this watermaker output and salinity guide can help crew organise the symptoms before requesting service.
Product-water diversion is the final safeguard
The product-water quality controller and diversion arrangement must remain operational. HRO's controller keeps un-potable product water diverted to discharge rather than allowing it into the potable tank.
Crew should confirm that diversion continues until the controller accepts the product water. Never override the diversion valve simply to fill the tank. If the controller or valve cannot reliably reject un-potable product water, stop using the system and arrange an inspection.
Post-treatment equipment does not change the feed-water restrictions. HRO recommends its optional UV steriliser where the feed inlet is near a polluted source such as a raw-sewage outlet, but describes UV as post-treatment protection. It is not permission to draw visibly polluted, oily or chemically contaminated water through the intake.
Where to run a watermaker around Mallorca
There is no supported rule that a particular Mallorca bay, marina or distance offshore automatically provides suitable feed water. The decision must be based on the condition of the water at the vessel, together with the instructions for the installed watermaker.
Open water generally presents a lower harbour-contamination risk than an enclosed marina, but it should not be treated as automatically clean. Before starting, inspect the water immediately around the yacht. Reject it if there is visible oil or fuel sheen, paint or chemical pollution, sewage signs, heavy turbidity, red tide or any other visible contamination.
Spectra's Ventura manual offers a simple visual screen for harbour testing: avoid water that cannot be seen through or that shows visible contamination. Clear appearance alone does not prove the absence of oil or chemicals, so this check must sit alongside the manufacturer's operating limits and the yacht's pressure, production and salinity records.
If a Spectra Ventura must be tested briefly while the yacht is in a marina, its manual says to monitor the water around the vessel carefully. Where safe testing is not possible, the manual provides an artificial-ocean test method. Follow the model-specific procedure rather than improvising a test feed.
What crew can check safely
Crew can make useful observations without dismantling the high-pressure circuit or attempting to recover a contaminated membrane.
- Inspect the feed water. Before opening the intake, look immediately around the yacht for oil or fuel sheen, paint, chemical pollution, sewage signs, turbidity and red tide. Do not run the watermaker if any contamination is visible.
- Record the operating condition. Check and log prefilter differential or low pressure, production and salinity. A pressure shift combined with reduced production after near-shore intake calls for prefilter inspection.
- Check product-water diversion. Confirm that product water continues to discharge until the quality controller accepts it. Do not override the diversion function to send rejected water into the potable tank.
- Respond to odour. If product water develops a foul or rotten-egg smell, stop the system and inspect the prefilters for the condition described by Spectra.
These checks are most useful when the readings are logged consistently. Pressure, production and salinity changes can then be reported together, rather than as unrelated symptoms.
When to call an engineer
Stop operating the watermaker and request technical help when the intake has drawn oil, fuel, chlorine-treated dock water, sewage-contaminated water or another chemical contaminant. Continuing to operate is not a useful flushing strategy where the membrane or feed circuit may already have been exposed.
An engineer should also inspect the system when contamination exposure is followed by abnormal product quality, pressure or flow. Report what was visible around the boat, the recorded readings, any smell from the product water, and whether the system was still diverting rejected water.
Call for service if the automatic salinity and diversion function does not reliably reject un-potable product water. The same applies when a pump, membrane or feed circuit has been exposed and the system's condition cannot be established from crew checks.
Blueward Marine provides yacht watermaker service in Mallorca. Book through the online technical intake with fault details and photos, or call the 24/7 emergency line on +34 971 251 374.
Frequently asked questions
Can I run a yacht watermaker in a Palma marina?
Do not treat a Palma marina as automatically suitable. Spectra says enclosed marinas carry a much higher contamination risk than open water and advises against using opaque or visibly contaminated marina water. Inspect the water around the vessel and follow the installed watermaker's manual. If safe testing is not possible, use the manufacturer's alternative test method where provided.
Why is oil in a watermaker intake so serious?
Spectra says oil in feed water can permanently damage watermaker membranes. It recommends an oil/water separator when making water in harbours or polluted areas, but this does not make visibly contaminated water acceptable. If the intake has drawn oil or fuel, stop operating and arrange an inspection of the membrane, pump and feed circuit.
Can a UV steriliser make harbour water safe for a watermaker?
No such conclusion is supported by the manuals. HRO describes its optional UV steriliser as post-treatment protection and recommends it where the feed inlet is near a polluted source. EchoTec separately says not to operate its system on contaminated feed sources containing oil, chlorine or other chemicals. UV does not remove the need to reject polluted feed water.
Sources and further reading
These references informed this guide. Follow the procedures and limits for the equipment installed on board.