The Definitive Guide to Water Weight Management

Managing water weight on your flights is essential to the efficiency of your aircrafts and to reducing your total carbon emissions. By carrying less water weight, you can reduce your fuel consumption and help reach your sustainability goals.

Everything you need to know

This guide is designed to provide you with as much broad information as possible on the subject of potable water management. Whether you are thinking of improving your existing water weight management process or installing a new one, this will give you a better understanding of the benefits of managing your flight water weight more effectively.

In this definitive guide to water weight management, we will look into why installing a potable water management system is a low-cost, smart investment to make in an era with an increased focus on the environmental impact of carbon emissions. We will look into the effects of carrying too much water, the problems with the practice of ‘fill to spill’ and the advantages of better water weight management.

We explore how potable water management systems can shave your weight burden, help you achieve your sustainability goals and bring you in line with the CORSIA initiative. Along the way, we investigate International Water-Guard’s Pre-Select potable water management system and explain how it works, to help you determine whether it is the right solution for you.

So if you are looking to manage your flight water weight more effectively and further your green ambitions - then search no further. This Definitive Guide to Water Weight Management is exactly what you need.

Water Weight Management Topic Overview


How does water weight management enhance performance?


The advantages of better water weight management


Measuring your water consumption


How to instal a water weight management system


How to save on fuel burn and commit to sustainability

Chapter 1 of 5

Performance -

Carrying too much water on board

In an industry where sustainability is at the forefront of everyone’s mind, looking at water weight management is essential. Water weight and its proper management can impact an aircraft’s efficiency and result in a reduction of total CO2 emissions. This is more important than ever, as more and more airlines commit to CORSIA.

Unfortunately, current airline industry practice is inefficient when it comes to water weight management issues. We elaborate on why these practices are problematic and why the issue needs to be addressed.

There are very good reasons why water weight management should be given priority.

1.1 The Problem with ‘Fill to Spill’

The problem lies in the current practice of ‘fill to spill’. In preparation for a flight, ground crew fill the potable water tank to the overflow or spillage line without calculating how much potable water is actually needed. This is because they lack effective systems to accurately estimate the water needed for specific flights, so default to the ‘fill to spill’ policy. Unfortunately, this can lead to the aircraft carrying unnecessary extra water weight - as much as an excess of 440lbs/200kg in some instances.

This superfluous water weight is significant. Studies have shown that second only to winglets, managing potable water weight is the leading means to saving fuel.

1.2 Everything in Balance

In addition to the sustainability issues it causes, carrying surplus water volumes also impacts on the flight performance of the aircraft. Efficient functioning of the aircraft depends on the proper water weight and balance. The further the weight is placed from the centre of the aeroplane, the less satisfactory the plane will perform. Weight that is positioned in the tail of an aircraft, for example, will cause an induced drag and compromise the aircraft’s efficiency significantly.

1.3 Changing the Accepted Practice

With the exception of using a simple product that can gauge the amounts of water that an aircraft needs during a particular flight, the aviation industry has yet to settle on guidelines or mechanisms for accurately keeping track of and better controlling water weight on aircraft. In the meantime, airlines continue to ‘play it safe’ by carrying much more water than is actually required. In an age of pressing sustainability imperatives, this practice is not environmentally sound. Nor does it make financial sense, when airlines have the potential to lose a great deal of revenue in wasted fuel.

Chapter Summary

Water weight management can help an airline save on fuel costs and avoid inefficient weight imbalances on its aircrafts. It is also sound environmental practice for the airline industry.

Chapter Summary

‘Fill to Spill’

The practice of ‘fill to spill’ causes problems with carrying unnecessary extra water weight.

Balancing Aircraft

Managing water weight can mitigate imbalances on aircraft that can lead to inefficiencies.


Water weight management is both environmentally and financially sound.

Chapter 2 of 4

Advantages -

The advantages of better water weight management

Managing the amount of fuel burned is essential to every airline. But it’s not the only area of cost savings. Optimising water weight also presents airlines with a chance to save on costs.  

Most airlines do not currently handle their potable water systems effectively. The practice of commercial operations is to fill their water tanks to the brim before a flight, regardless of how much water the flight actually needs. By employing water weight management systems, airlines can save on substantial fuel consumption.

2.1 Providing Some Certainty

The two ways in which airlines currently estimate the amount of water needed to be allocated to ground aircraft are both problematic. The first is the fill-to-spill approach which is the default position when there is no water management procedure. The second is by following an airline’s individual procedures. However, it can be difficult to ensure these are implemented by all ground staff around the world and they are often ignored.  

Potable water management systems, such as International Water-Guard’s Pre-Select, provide certainty about the water requirements for each flight. 

2.2 Savings on Fuel Costs 

The global instability of recent years has caused great instability in fuel prices. In early 2022, the spot price for jet fuel exceeded $4 per gallon for the first time since 2008. With fuel prices accounting for as much as 40 percent of an airline's annual expenditures, wasting fuel by carrying more water than is needed is an unnecessary cost that few airlines can afford. Lower water weights mean less fuel consumption, cost savings and fewer carbon emissions.

2.3 Extra Cargo Space

Carrying only the water needed for a flight doesn't just save on fuel costs. When airlines carry only the water needed for a given flight rather than indiscriminately 'fill to spill', the savings in water weight free up precious revenue-earning cargo space.

Chapter Summary

Smart water weight management brings many advantages to the airline industry. It is a go-to solution for providing some certainty in water consumption estimations, saving on fuel costs and freeing up weight that could instead be used to carry cargo. 

Chapter Summary

Providing Certainty

Potable water weight systems can provide some certainty to water management.

Fuel Savings

Potable water management helps the airline industry achieve a net zero carbon footprint.

Extra Cargo Space

Effective potable water management can free up revenue-generating cargo space.

Chapter 3 of 5

Measure -

Initiating a new system or improving a current system?

There are many ways to reduce fuel burn and some of them are more obvious than others. Managing the weight of the potable water an aircraft is carrying is one of the least obvious ways. But studies have shown that effective water weight management systems can result in substantial savings in fuel consumption. 

It doesn’t matter whether an airline has the equipment or processes in place for reducing the amount of water used on each flight. Even without a current system, airlines can benefit from managing their water weight and, at the same time, gathering valuable data about the amount of water used for future consideration. 

3.1 Extend Your Current System

To save significant water weight, airlines can augment their existing system by fixing standpipes in the potable water tanks to curb the water levels. In this way, it is possible to limit a full 60gal tank of water to 40gal and you will shave approximately 33% of the weight. 

If combined with a water weight management system such as International Water-Guard’s Pre-Select, the weight saving will increase substantially. A water weight saving of 90% can be achieved, for instance, through a tank configured to have 100% equal to 40gal. And it doesn’t mean the standpipes need to be removed, although this will save further weight. 

3.2 Measure Your Consumption

Many airlines have yet to take advantage of the savings that potable water management can make to fuel burn and carbon emissions. If your airline is one of them, then now is the time to start understanding and measuring your water consumption. You can’t manage what you can’t measure, right?

A Pre-Select system will slice up to 90% of the water weight from the aircraft—subject to each flight’s duration and distance. That corresponds to 440 lbs/200kg or approximately 2 passengers with carry-on bags.

3.3 Big Rewards

Managing water weight on an aircraft can reap huge rewards with little effort and modest expense. Every airline that comes on board with the concept will optimise its fuel efficiency and keep unnecessary weight burdens at a minimum. Even if an airline is already equipped with some sort of weight management system, International Water-Guard’s products can further help to achieve these goals.

What are the benefits of more efficient potable water management?

Chapter Summary

Whether an airline has equipment or processes in place for reducing water used on flights or not, it can benefit from managing its water weight and planning for future water consumption.

Chapter Summary

Extend Current Systems

Airlines can augment their existing systems and significantly reduce water weight.

Measure Consumption

You can’t manage what you can’t measure. Start understanding and measuring water consumption.

Reap the Rewards

A low cost, high reward investment that can optimise fuel efficiency and reduce carbon emissions.

Chapter 4 of 5

Implementation -

What’s behind potable water management: Its functions and costs

If you’re looking to reduce your fuel consumption and carbon emissions, potable water management is a sure step to achieve just that. But just how straightforward is it to implement a water management system?  

International Water-Guard's Pre-Select system will show you just how easy it is to keep an eye on and control each flight’s water consumption.

4.1 What’s Behind Pre-Select?

Before potable water management systems, ground crews were only able to guess how much water to carry on board. In the absence of formal processes, they adopted the “fill-to-spill” practice or relied on water gauges that were often imprecise. 

But with potable water management systems such as Pre-Select, the flight crew can set the water limits and the water will spill over when reaching that limit. This is achieved through a touchscreen controlled by the flight crew or through a dispatch received via a GMS module. The ground crew responsible for filling the water is unaware of the fixed system, which eliminates the uncertainties inherent in ground crews determining the water levels.

4.2 How Long Does it Take to Instal?

It takes about 30 staff hours to set up a Pre-Select system, including the wiring for electricity. This means a two to three-person crew can instal a fully operational system in just a day. 

After the system has been installed, it can be good practice to set it at 75% full initially, while data is collected on water consumption during each flight. Once the system gives the data on the precise uses of water, levels can be adjusted accordingly. Of course, it’s perfectly possible to set the system at 100% full but the object is to immediately see the ROI in the savings made!

4.3 Commitment to Sustainability

The fact that there has been a decreasing use of in-flight potable water is not unknown to the aviation industry. But despite this knowledge, the airline sector has not dealt with the nexus between water weight and its impact on fuel consumption. 

With the present demand for CO2 reductions as part of the aviation industry's goal of net-zero emissions by 2050, airlines must show their commitment to sustainability. This means doing everything possible to curtail carbon emissions.

The Pre-Select system of International Water-Guard is an intelligent solution to water weight issues and an important step in reducing fuel burn and emissions. 

Chapter Summary

The Pre-Select is a simple, intuitive system that's easy to install. It includes:

Chapter Summary

A System Controlled by Flight Crew

Flight crew can control water limits for each particular flight - there's no need for ground crew in the process.

A Day to Install

A 2-3 person team can install Pre-Select within a day and once set up, it can be used immediately.

A Commitment to Sustainability

Pre-Select manages the nexus between water weight and fuel consumption and helps airlines demonstrate their commitment to sustainability.

Chapter 5 of 5

Sustainability -

Potable water management: Cut back on fuel and go green

There are a heap of advantages to installing a potable water management system. The primary one is, of course, the savings on fuel burn. But this just doesn't boost an airline's bottom line; it also benefits the environment. Less water weight means less fuel consumption which means fewer carbon dioxide emissions. The IATA’s research backs this up. 

Hundreds of pounds of weight can be shaved from the water load with the installation of water management systems such as International Water-Guard’s Pre-Select. This has to be music to the ears of an airline looking at every possible way of limiting the weight it carries and reaching its sustainability goals. 

But the benefits don't stop there. 

5.1 The Power of Data

Pre-Select allows an airline to monitor its water use and determine water requirements on a flight-by-flight basis. Data is stored and can be used in real-time, allowing the airline to configure and customise water levels in a flash. Only by measuring and storing data on precise water use can an airline really improve its potable water system. 

5.2 Plan Your Flights

The data stored in Pre-Select is assessed by the system’s software to assess water usage. This gives the flight crew or dispatch the ability to ascertain the levels of water needed for any given flight. Ground crews continue with their task of filling water, without even necessarily knowing the system is installed.

Water management systems are also able to keep track of the system’s parts to ensure they are continuing to operate effectively. For example, Pre-Select will alert the operator that the system must be calibrated in order to maintain its 1% accuracy.

Pre-Select eliminates the need for the ground crew to be involved in determining water levels, so there’s no need to train staff when rolling out the system. Ground crew will simply receive the same signal as always when the water levels exceed the predetermined limit. And for the inflight crew or dispatch, the system's touchscreen is super intuitive and easy to use. 


The aviation sector's carbon offsetting programme CORSIA is a major tool in achieving the ambitious net zero goals. As of January 2023, 115 countries were participating in the programme, demonstrating the widespread view that the programme will be a key part of the global environmental movement.

The Pre-Selection water weight management system is a low-priced way for airlines to increase their efforts to be greener.

Chapter Summary

With the power of data, International Water-Guard's Pre-Select enables airlines to make proper plans for their flights while saving fuel and being in line with the CORSIA initiative. 

Chapter Summary

Power of Data

The data generated by Pre-Select enables accurate flight preparation in terms of water usage during a flight.

No Training

Pre-Select does away with ground crew determining water levels - there's no need to train staff when introducing the system.

Carbon Offsetting

Pre-Select helps airlines go greener and adhere to CORSIA.