Now you may be thinking that these are some very strange questions to be asking, but at the same time, something that we all really want to know when we think about submarines…

Have you ever wondered…


Pressurised seawater is used to flush the toilets on a submarine. A simple ball valve operates the flush on the toilet which enables the toilet to be ‘plumbing free’. Once flushed, you then manually turn a valve next to the toilet to refill the bowl. If you wish to get really technical, then here are the exact steps to follow:

  1. Open lever operated drain valve
  2. Open flush valve and keep open long enough to thoroughly flush both the bowl and its drainline
  3. Close the drain valve
  4. Allow several inches of water to cover the drain valve before closing the flush water

There is a lot that goes on behind the scenes with regards to the toilet systems on a submarine to ensure hygiene is kept as a top priority and that floods don’t occur.

Further down the pipes, there are valves that can be used to isolate different sections so that when the waste is disposed of, the pressure only goes the way intended and it doesnt come back up towards the user… you really wouldn’t want that! 

There is a lot of engineering, processes and training that goes on behind the scenes to ensure that the crew understand how to execute the procedure from the moment they start doing it.

The reason that the toilet is backfilled with water is to create a seal to stop any smells from coming through in the event that there is any leakage past the ball valve, not too dissimilar to your toilet at home. 


Have you ever wondered how to take a shower onboard a submarine? Then simply read on…

The showers on a submarine are set up much like the ones in your home, well kind of. They have hot and cold water access with a recirculation pump so that the water stays hot so that you can use it quickly and efficiently by minimising water usage.

Reducing water usage is a constant major driver for submariners. The crew are able to make lots of water but the less water they use, the less water they have to pump off which results in them being as quiet as possible and retaining their stealth. 

One of the major goals that submariners strive to achieve is to minimise usage and reduce waste generation whilst onboard the submarine. 

With that being said, your next question may instantly be “How long should I stay in the shower for?” The easy answer is, as long as you want but traditionally should be between 3-5 minutes.

To get the most efficient wash possible, many submariners will get themselves nice and wet, shut off the water, soap up, turn the water back on and rinse off. This may not be the most enjoyable way to shower, but when onboard a submarine, efficiency and waste prevention counts for everything. 

Now you know…

Submarine Shower Blog Post