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Clean drinking water is something most people take for granted. But for seafarers and offshore workers, having safe water every day depends on complex systems that must be carefully maintained and monitored.

Imagine finishing a 12-hour shift on an offshore platform in the Gulf of Mexico. You turn on the shower, and clean water flows as usual. It may seem simple, but behind that water is a system of storage tanks, filters, pipes and disinfection equipment working around the clock.

Offshore platforms and ships need large amounts of drinking water every day. It is used for drinking, cooking, showers and other daily activities. Keeping that water clean is essential, especially when workers spend weeks at sea and are far away from hospitals or other medical support.

If a water system is not properly maintained, harmful bacteria and other contaminants can spread. This can cause serious illnesses and put the entire crew at risk. Water tanks and other equipment can also create physical dangers, including the risk of getting trapped or being exposed to toxic gases.

Understanding how these systems work and what can go wrong is an important part of protecting maritime workers.

Where Does Drinking Water Come From?

Offshore platforms and ships usually get their drinking water in two ways: bringing it from shore or producing it onboard using desalination.

1. Bringing water from shore

This process is known as bunkering. Potable water is loaded from land-based facilities onto supply vessels and transported to offshore platforms or ships.

The water is then transferred through special hoses into storage tanks.

These hoses must only be used for drinking water, properly capped when not in use and disinfected if they have not been used for more than 14 days. Water samples must also be collected and tested before bunkering begins.

Problems can occur if hoses are not properly cleaned or connections are not sealed correctly. Even if the water was safe when it left the shore, it can become contaminated during transportation or storage.

2. Producing fresh water from seawater

Another option is desalination, which allows ships and offshore platforms to produce their own drinking water directly from seawater.

One commonly used method is reverse osmosis (RO). It works by pushing seawater through special membranes under high pressure. These membranes allow water molecules to pass through while removing dissolved salts, minerals, bacteria and viruses.

The process starts by collecting seawater, usually from around 20 to 30 feet below the surface to avoid some surface contaminants.

The water first passes through filters that remove larger particles, dirt and organic material. High-pressure pumps then push it through the RO membranes. Fresh water is collected on one side, while concentrated saltwater, known as brine, is discharged back into the sea.

Depending on the installation, modern RO systems can produce anywhere from a few hundred to tens of thousands of gallons of fresh water per day.

Although this method uses less energy than older thermal desalination systems, it still requires regular maintenance. Dirt, mineral deposits and biological growth can build up on the membranes and reduce both performance and water quality.

How Is Water Stored and Delivered?

Producing or receiving clean water is only the first step. It must also remain safe while being stored and transported around the vessel or offshore platform.

Storage tanks can hold anywhere from a few thousand to tens of thousands of gallons. They must be made from approved materials that do not release harmful substances into the water.

Steel tanks are commonly used, but they can develop rust over time. Corrosion can affect water quality and create conditions that encourage bacterial growth, including Legionella.

From the tanks, a network of pipes delivers water to showers, kitchens, crew cabins and other areas.

Older installations often have steel pipes that can corrode over the years. Newer systems may use stainless steel, copper or plastic materials to reduce these problems. However, older offshore platforms may still have decades-old piping that requires regular inspection and maintenance.

Water temperature is another important factor.

According to the CDC, hot water should be stored above 140°F (60°C), while cold water should be stored and circulated below 77°F (25°C). This helps reduce the risk of Legionella growth, although the bacteria can still survive at temperatures as low as 68°F (20°C).

Chlorine is also used to control harmful microorganisms. Offshore installations typically maintain chlorine levels between 0.2 and 0.5 milligrams per liter.

However, keeping the correct levels throughout the entire system can be difficult, especially in sections of piping where water does not move regularly.

Legionella: A Serious Risk for Offshore Workers

One of the biggest water-related health concerns for maritime and offshore workers is Legionella pneumophila.

This bacterium causes Legionnaires' disease, a serious type of pneumonia that kills approximately 10% of people who become infected. People over 50, smokers and those with weakened immune systems are at greater risk.

Legionella can naturally exist in freshwater environments. The problem begins when it grows inside man-made water systems, such as storage tanks, pipes and showers.

Workers can become infected by breathing in tiny contaminated water droplets. These droplets can be produced by showers, cooling towers and other equipment that creates water mist.

The risk is particularly concerning aboard ships and offshore platforms, where many people share the same water system.

A 2018 study tested water samples from 360 non-passenger merchant vessels docked at UK ports. The results showed that 58% of the vessels had samples testing positive for Legionella. In 27% of the samples, levels were above the upper action limit, meaning immediate action was required.

According to the CDC, Legionnaires' disease usually develops between 2 and 14 days after exposure.

Common symptoms include:

• Fever

• Cough

• Shortness of breath

• Muscle aches

• Headaches

The disease does not normally spread directly from one person to another. However, if a shared water system becomes contaminated, several crew members can become ill at the same time.

This is especially dangerous offshore, where medical facilities are limited and getting a sick worker to shore can take time.

Other bacteria and viruses can also contaminate drinking water. Coliform bacteria, including E. coli, can indicate contamination from human or animal waste and cause gastrointestinal illness.

Norovirus and similar infections are another concern. When workers live and work in close quarters, stomach illnesses can spread quickly through the crew.

What Rules Protect Drinking Water at Sea?

Several regulations and organizations help establish standards for drinking water aboard ships and offshore installations.

In the United States, the U.S. Coast Guard is responsible for vessel sanitation and potable water quality on ships under its jurisdiction. It oversees requirements for water production, storage and distribution and carries out inspections to check that vessels meet federal sanitation standards.

Internationally, the Maritime Labour Convention (MLC) 2006 established important requirements for crew health and living conditions. The convention entered into force in 2013.

Under Regulation 3.2, ships must provide enough safe drinking water for crew members. This includes water for drinking, preparing food and personal hygiene. The water must meet appropriate quality standards and must not cause short-term or long-term harm.

For fixed offshore platforms in U.S. federal waters, the situation is less straightforward. The Bureau of Safety and Environmental Enforcement (BSEE) oversees offshore safety and environmental protection, but potable water quality on fixed platforms has less clearly defined federal oversight than it does on vessels.

As a result, industry guidelines and company safety management systems play an important role in maintaining water quality.

Clean Water Is Essential for Crew Safety

Modern technology already provides several ways to produce and maintain safe drinking water offshore. Reverse osmosis systems can turn seawater into fresh water, modern piping materials can reduce corrosion, and monitoring equipment can help identify contamination before it becomes a serious problem.

However, these systems only work properly when they are installed, inspected and maintained correctly.

For seafarers and offshore workers, clean drinking water is not simply a convenience. It is a basic requirement for staying healthy and carrying out demanding work safely.

When a crew spends weeks away from shore, even something as simple as turning on a shower depends on a water system that must work reliably every single day.

Original post: https://gcaptain.com/how-potable-water-quality-impacts-crew-health-safety/