What are the benefits of more efficient potable water management?

Sustainability | Dec 08, 2020 | By Satair | 3 min read

There is no question that fuel burn management is vital to overall airline savings, but what about water management? What are the immediate cost effects of maximising the potable water weight?

With the sheer volume of moving parts that need to be in perfect sync in order to get 50 (or 100) tons of aluminium and steel to fly through the air at 30,000 feet, unfortunately there are bound to be some inefficiencies. (Note: 50 US Tons = 100,000lb or 45,360kg)

One of those inefficiencies comes from the way in which the majority of commercial airlines handle their potable water management systems. In fact, to date the standard is to simply fill the water tank to full capacity prior to each flight, adding an additional 500lbs. or so to a flight, regardless of how much of the water is actually used during the flight.

Addressing this issue through the use of a potable water management system can substantially reduce fuel burn and an aircraft's carbon footprint.

Water weight management: Are you starting from scratch or further optimising your system?


Removing the guesswork

Effective water management can essentially remove the guesswork from how much water will be needed during select flights. Currently, ground operations work with a “fill-to-spill” process that is essentially no process at all.

We spoke with Steven Bis, President of International Water-Guard Industries, and asked how ground technicians know how much water to replace in an aircraft when it is on the ground, and he had this to say:

“Effectively there are two ways. The first, and most common, is to just fill-to-spill. The second involves procedures issued by a specific airline.

Both options are flawed. The former because it indicates a complete lack of process for water management and the latter because there is no way to ensure that the various ground crews around the world follow the procedures issued by the airline.  As a matter of fact, most manual potable water management procedures are not followed by ground crews."

Without products like the Pre-Select system that Steven Bis’ company provides, even if an airline wanted to engage in potable water management, it would essentially have to track usage manually for every flight. This information would then need to somehow be conveyed to ground crews after every landing.

How does potable water management work? And what does it cost?

Photo of an aircraft in the sky

Extra Cargo Space

At the time of writing this article, passenger load is nowhere near what it was just a few months ago, but this does not mean that the need for potable water regulation is not essential—nor will it cease to be in the future. With the cost of efficiently operating an aircraft more contingent than ever on retaining revenue, removing excess water weight can allow an airline to free up cargo space and increase revenue. Essentially, with the removal of a potential 450lbs (181kg) of weight, airlines can make use of that free space with cargo that can help return the cost of aircraft operation.

Fuel efficiency

At the time of reporting on this subject, fuel prices have dropped dramatically. This might lead you to think fuel efficiency is not an immediate concern. The fact of the matter is that flight frequency will return, and thus fuel costs could inevitably rise again. Additionally, you might not think that saving water would correlate with saving fuel, but at the end of the day, fuel efficiency is what potable water management is all about. Less weight means less fuel burn and less greenhouse gas emissions.

“A general guideline is that for every 1kg of extra weight added to the aircraft, they need/burn 0.04kgs of fuel. So by preventing the upload of 300lbs (140kg) of unnecessary water (for example), the airline would save 12lbs (5.5kg), or about 2 gallons (7.5L) of fuel per hour per flight.  Depending on the cost of fuel, length of flight, and number of flights, this would be extremely significant,” Steven Bis explained when asked how water weight correlates to fuel efficiency and sustainability.

“Using the same example of saving 300lbs (140kg) of water weight, that corresponds to over 60lbs (27kg) of carbon emissions saved per hour.  In dollars, that would save an airline about $3,000 per year.”

The simple solution

For all the talk regarding sustainability and the reduction of aviation’s global carbon footprint, potable water management sounds like a rather straightforward solution. However, in what will inevitably be a long hard-fought battle to reach a carbon-neutral aviation industry, even the little steps can make a significant impact.