One of the biggest problems facing the world is the lack of clean, readily-available drinking water. There are 844 million people that live without clean drinking water. That’s one in every ten people. Although there are many charities that help bring clean water to these communities, there is one seemingly simple solution that isn’t being tapped into: ocean water.

Covering more than 70% of the Earth’s surface, it’s no wonder people have been trying to drink this water for centuries. In its natural form, ocean water is so packed full of salt that it actually makes people more thirsty. It also can contain harmful chemicals and other debris. Scientists have been exploring ways to make this process more efficient and accurate, but the world just isn’t there yet. Unfortunately, there are many hurdles standing in the way.

The first one is cost. 1000 gallons of freshwater costs roughly $2.00 for the average US consumer. However, desalination can drive costs to $2.50-$5.00. This can actually cause water bills to nearly triple. Aside from the consumer costs, there is also the cost of opening a plant. In 2015, California opened the US’s largest desalination plant, which cost $1 billion. To put that cost into perspective, this plant will only provide enough water for 7% of the total needs for the San Diego area. This means entirely desalinated drinking water is a long way away, just from the cost.

On top of the cost is the difficulty of the process. The science is complex, but the basic idea is that salt is dissolved in the water, so it is incredibly difficult to separate. This can be done through evaporation or by forcing water through a sieve-like material that only allows H2O molecules to pass through. Not only is this prone to failure, but it also requires a large amount of energy. This energy can increase the amount of greenhouse gas emissions and potentially make problems of a decreasing freshwater supply worse.

Furthermore, it can be costly, time-consuming, and a hassle to ship water inland. Consider the many US states that do not border the ocean. If they also have a need for water, how can it get there? Shipping tons of water is not cost effective or quick, so there may need to be some form of pipeline system (similar to gas pipelines) to funnel water to these areas. The issue here is that pipes can burst or accumulate non-water materials, which would need to be filtered out in homes. It would also be incredibly expensive to fund a project of this magnitude, and it would create a dependence on desalination plants that could potentially cause millions to go without water, should a disaster occur.

Relying on desalination has one last difficulty, and that is time. The process can be time-consuming in and of itself, which could lead to problems down the line. For example, desalination may not be able to keep up with demand, which could lead to legislature mandating limited water use, or applying a large fine to those who use past that limit. This would be a headache for residents and those in government positions, as the question of the right to clean water would naturally come. Relying solely on desalination is a slippery slope, so government officials are taking their time in making sure it’s a worthwhile investment.

It would be great if the world were able to easily and affordably desalinate water. Millions of people would have better access, but there are many obstacles in the way. Until science is able to resolve all of these issues, don’t expect to take a sip from the ocean anytime soon.