How Many Restrooms Are Enough on a Plane?

The airlines have made a startling discovery – if they take out a restroom on a typical plane, they can add another three seats instead.

And so inexorably over the last decade or so, we’ve seen the number of restrooms on planes decrease, while the number of seats have increased.  The ratio between bathrooms and seats/passengers is getting even worse than it would first seem, because at the same time, average passenger loads on planes have been increasing.

So whereas before there might have been a plane with say 150 seats, an average load of 65%, and four bathrooms, meaning that 98 passengers (65% of the 150 seat capacity) shared four bathrooms, ie one bathroom per 24 1/2 passengers, now there might be 160 seats, an average load of 80%, and three bathrooms, meaning 128 passengers and three bathrooms, or 43 passengers per bathroom – nearly twice as many passengers now having to share each bathroom.

The bathroom congestion is getting substantially more serious than it would first seem.

Now, I don’t know about you, but it seems common for many people, as they age (and men in particular), to need to make more and more frequent stops in restrooms.

Another two issues – it seems that pilots are ever more cautious and leave the seat belt sign on, for no sensible reason, for longer and longer portions of flights, meaning there are fewer minutes when the toilets are available.  Add to that TSA ‘security’ regulations that are sometimes used to prevent passengers from lining up to wait their turn in an orderly manner, and the tension levels rise still further.

So when you add all this together, we have a terrible combination of problems :

• There are fewer toilets on many planes
• The same planes not only have fewer toilets, but may have more seats too
• More seats are filled with passengers than ever before, meaning the real number of people served by each restroom has increased even more sharply
• People visit the toilet more often
• There is less time per flight for people to access the toilets, increasing the pressures on the toilets when the fasten seatbelt sign is not illuminated
• TSA restrictions make it harder to queue in an orderly manner and to be sure of getting your turn in sequence with everyone else

All in all, a nasty situation.

So how many restrooms are ‘enough’?  That’s hard to answer, although it is usually obvious when an airplane has too few!  For example, reader Sandy writes

Just wanted to give you some information regarding a recent trip we took to Boston on United.

No problems on our trip going, but our return flight (Boston to SF) was on an updated 737.  This configuration adds more seats, but on a long flight made it impossible for restroom issues…  The biggest problem was the shortage of restrooms for a plane full of passengers (approximately 160) on a 6 1/2 hour flight. There were only 3 restrooms, one in first class, 2 in the rear.

There was no place to stand and wait, which created a real bottleneck with people waiting in the aisle at least half way back…no way to get around, a real nightmare!

Then the attendants kept announcing that they needed to move the food carts, so they wanted people to sit down. The food carts moved VERY slowly as they were selling food.

I hate to think what would have happened it there’d been an emergency restroom need!  Once again, the airlines are making plane travel one of endurance, and the customer not only has to deal with inadequate and uncomfortable seats, but inconsiderate planning for increasing their profits at the expense of basic human needs.

It isn’t clear exactly which 737 configuration applied to Sandy’s flight, and United has various configurations for its 737-800s ranging from a best case 152 seats and 5 toilets through to a worst cast 187 seats and 3 toilets.  That’s a difference between one toilet per 30 seats and one toilet per 62 seats.  And therein lies the potential problem – some planes are well equipped with toilets, but some are appallingly shortchanged.

Let’s look at that three toilet scenario a bit more.  One of the three toilets is up front for first class only, and the plane has 16 first class seats.  One toilet for 16 people is a great ratio, as you’d hope with first class.

But that means the other two toilets have to serve the needs of 171 coach class seats between them – in other words, one toilet per 85.5 passengers.  And that’s far from satisfactory.

In a best case scenario, maybe that is acceptable (although we think not).  But, what happens if/when one of the toilets suffers a problem and is taken out of service?  Or a passenger is very unwell and pretty much lives in one of the toilets for the entire flight.  You now have only one remaining toilet for 171 passengers.  And that truly isn’t going to work.

Let’s try to get a feeling for relevant measures in terms of toilet needs on planes.

Different Rules for Short-haul and Long-haul Flights

At the risk of stating the obvious, most people can manage without a bathroom break on a short flight of an hour or so.  And many people can manage on a flight of 2 or 3 hours.

But when we start looking at total time on a plane of four or more hours, most people will wish to go at least once, and some people will wish to visit multiple times.  Even those who don’t end up using the facilities still want to be reassured that there is convenient access to them if they might be needed.

This means that the toilet ratio on a short-haul flight can be much less than on a long haul flight, because some people will not use the toilets at all during the flight; whereas the longer the flight, the greater the toilet usage will be.

Toilets Are Used for Many Things

Unlike a typical bathroom arrangement on the ground, toilets are ‘multi-purpose’ spaces in planes.  They aren’t just used for the obvious purpose.  And even when they are used for the obvious purpose, the time a person takes there is longer than elsewhere because the same space is used for then washing their hands.

Airplane toilets are used for many other purposes too.  For example, they can be used as changing rooms – some people change into ‘on plane’ clothes at the start of a long journey and back into ‘street’ clothes prior to landing at the other end.  They are also used as baby changing rooms too, of course.  Or as powder rooms for women to put on makeup, and for men to shave.

There are some people who spend astonishing amounts of time in the toilet for purposes that can’t be guessed at, and dare we hint at those rare but occasional situations when two people emerge from a toilet together?

The point we’re making here is that, on land, toilet facility specifications are generally supplemented by additional space for hand-washing, applying makeup, getting changed, and whatever else.  The total time you spend in a bathroom facility on the ground is split between some time in the cubicle and other time in the other parts of the bathroom area.  So whatever number of cubicles are required on the ground needs to be increased on a plane because the cubicle is occupied not just for the ‘main’ purpose, the same as on the ground, but for all the other purposes too.

There Are No Alternatives on a Plane

If you’re walking through a terminal concourse, sometimes there’ll be a bathroom out of service due to the janitor doing things, or maybe a bathroom will be congested due to a sudden rush of people coming off a flight and going straight to the bathroom (I wonder why!).

That’s no big deal.  We simply walk on 50 yards or so and there’s another set of bathrooms available to us.  The same is true in malls, in office buildings (just go up or down a floor), and pretty much everywhere else.  On the ground, there are more ’emergency alternate’ options for bathrooms if the first choice of bathroom is not available.

But, on a plane, if the bathrooms are all out of service or in use with long queues, what options do you have (that won’t get you arrested)?  None!  This means that the toilet ratio on a plane has to be more generous than on the ground, to reflect the fact that if things go wrong, there are no other options on the plane, unlike on the ground.

People Use the Toilet More on a Flight

We don’t have anything to support this perception, but we feel it may be true that people use toilets more on a flight than elsewhere.

One reason is because they may drink more than normal (all those free sodas and coffees, and even the chargeable beverages, all need to go somewhere) and then while sitting there bored and waiting for the flight to finish, one can more quickly focus in on messages from one’s bladder.  Even if they don’t drink more on the flight, some people will while away the waiting time in the terminal either with a morning cup of coffee or an afternoon/evening adult beverage, adding to their ‘liquid load’.

In addition, with the recommendations these days to exercise on a regular basis on a longer flight to minimize DVT risks, many people will get up, walk around, and while they are up think to themselves ‘I may as well stop at the bathroom’.

A similar situation occurs when an aisle seat passenger has to get up to allow an inner seated passenger to go to the bathroom.  Many times the aisle seated passenger might think ‘Oh heck, I’m up now, why don’t I go to the bathroom too’.

Sometimes people have been rushing to make their flight, and to save time they’ve consciously delayed going to the toilet for an hour or hours prior to boarding the plane, so they are starting their journey from a more full than normal bladder situation.  Others wish to ‘hit the ground running’ at the other end, so will deliberately use the toilet shortly before the plane comes in to land just so as to have one less thing to bother about after landing.

Add this all up and it seems fair to say that people use toilets at least as much on planes as they do on the ground, and probably more than on the ground.

What the Law Says About Toilet Numbers

There are no US laws specifying minimum numbers of toilets on board planes.

There is also little guidance about recommended ratios of toilets to people in offices and elsewhere.  But the UK, with a very voluminous set of ‘Health and Safety’ laws, does provide formal toilet ratio numbers for workplaces on the ground.  Basically the ratio is one toilet to start plus one more for each 25 people or part thereof.

So in a workplace with 8 people, there would be a requirement for two toilets.  In a workplace with 28 people, there should be three toilets, and so on.

It seems reasonable to assume that British bladders and bowels are similar to American ones, and the same for most people in the world too.  Although, as an aside, we’ve noticed that in nations where public toilets are far and few between, and those that do exist are of poor quality, many of the locals have amazing endurance.

So if Britain says you need to have these numbers of toilets, it would seem fair to reason that a similar – or greater – number should apply on planes, anywhere in the world, just the same as on the ground in Britain.

A Time and Motion Analysis

Let’s approach the subject from the point of view of typical demands on toilets, and how many people each toilet, when working at close to capacity, can be expected to serve.

According to this site, the average person in the US uses a toilet 2500 times a year.  That is the same as 6.9 times a day.  If we say that for eight hours, while sleeping, they don’t use the toilet at all, that means these 6.9 uses are spread over 16 hours.

In other words, the average person in the US uses a toilet once every 2.3 hours.

Let’s keep that number as our approximate demand indicator, even though we say that on a plane we expect people may possibly use the facilities more frequently – both for ‘bathroom’ things and all sorts of other things as well.

The next question is how long does it take for an average visit to an airplane toilet.  Sure, sometimes people can be in and out in 2 or 3 minutes, but sometimes they are in there for way longer than 5 minutes – as you almost certainly know from past experiences standing uncomfortably outside an occupied toilet, waiting for the person inside to finish up and leave.

Let’s perhaps be optimistic and say the average toilet visit is fairly short – 3 minutes.

Next – we know that toilets aren’t available all flight long.  We know that from some time prior to pushing back until some time after the flight passes through 10,000 ft, the seatbelts sign is on and people can’t get up and go to a toilet.  The same at the other end, we know that the last 30 minutes or so of flight plus time on the ground taxiing to the gate is again a no-toilet time.

Plus there’s an unknown amount of time in the middle when the pilot will choose to turn on the Fasten Seatbelt sign, apparently just because he can.

Maybe it is fair to say that on average, toilets are available for 45 minutes in every hour of flight.

So mix all that together and what do you have?  This calculates to each toilet being able to comfortably handle about 35 passengers.  This is not remarkably out of line with the UK Health & Safety regulations, and actually comes fairly close to the number of toilets on many long-haul planes, where a ratio of about one toilet per 40 seats seems to be about ‘normal’ these days (this ratio has been slowly creeping up over the years).  One toilet per 40 seats is reasonably close to one toilet per 35 passengers (assuming the flight is not full).

You’re welcome to build your own set of assumptions and estimates and come up with any different number you choose.

Whatever the number you come up with, or if you simply accept our figure of one toilet per 35 passengers or 40 seats, that is close to a ‘best case’ scenario.  We know, for example, that there are ‘surge’ periods when more people all want to use the toilets simultaneously – for example, after a meal has been cleared away, or after a movie ends (this applies when one movie plays to the entire cabin simultaneously.  The new types of system where people can play their own movie choices on whatever schedule they wish has been very helpful to toilet needs), or when the fasten seat belt sign is turned off after an extended period of being on, or shortly before arrival.

Queuing Theory and Problems

There’s a reason the UK Health & Safety laws require one toilet per 25 people plus one extra ‘bonus’ toilet.  The extra bonus toilet recognizes the occasional situations when one of the toilets either is inoperable and out of service, or is being used for an extended period by just one person.

This is the same as waiting in line at the bank or to check in at an airline counter.  If there is only one agent working, the average wait to be served is more than twice as long as if there are two staff members; or, to put it another way, more than twice as many people can be served while keeping the average wait time down to an acceptable number, because on those occasions when one staff member gets stuck with a long difficult transaction, the other staff people are still working the lines.

Remembering also that airline toilets are sometimes prone to problems, and that if a toilet goes out of service on a flight, there’s usually no way that anyone is going to do anything to fix it for the balance of the flight (when did you last hear a call over the PA system ‘If there is a plumber on board, would you please ring your flight attendant call button’?) and it should be obvious that all flights need to have at least one more toilet than the theory would recommend.

Some Actual Airplane Examples

If you’re curious to know what type of toilet experience you can look forward to on your next flight, you can visit seatguru.com and look at their seating charts for each airline’s different airplane configurations.  These charts show the number of seats and the locations of the toilets, so you can quickly see how many toilets your class of service will have access to.

You’ll see substantial differences between the same model of plane – sometimes even within the same airline, and definitely across different airlines.

Not so obvious is the shift in toilet configurations over the years – for example, Delta used to operate CRJ-700 planes with 63 passengers and two toilets, and now they operate them with only one.  As per our analysis above, all airplanes should always have a minimum of two toilets, in case of problems with one of them.

Another example is Continental/United.  Their 777s formerly had four toilets for 48 business/first seats and six for the 235 coach class seats; then they were reconfigured to three toilets for 50 business/first and five for 235 coach class seats.

Some of the worst planes need to be considered in context of the flights they are operated on.  For example, Hawaiian Airlines has some 717s with 123 seats and only one toilet, but these are used for very short island hopping flights where most people won’t need to use the toilet at all.

But the ‘short duration flight’ excuse can’t be said of one configuration style of the US Airways fleet of 757-200s.  The plane has 164 coach class seats, and only two toilets – one per 82 seats (it also has a third toilet at the very front, but for the 12 first class seats only.

An even worse scenario can be found in some United 737-800s.  As mentioned above, some of United’s 737-800s have only two toilets for 171 coach class seats (plus a third up front for the first class cabin of 16 seats).  That can truly become cruel and unusual punishment.

To contrast United’s torture 737s, here is the seating diagram of an early Qantas 707-138 dating back to 1966.  You can see that the 20 first class seats/passengers had two toilets, and the 78 – 84 coach class passengers had three toilets – a ratio of one toilet for 26 – 28 seats/passengers.  In other words, there were three times as many toilets for a given number of passengers on the 1966 Qantas plane as there are on today’s United plane.

An earlier, pre-delivery document, suggests that initial plans were for a different cabin configuration with 40 first class and 50 coach class seats, with the same two first class and three coach class toilets.  This would have made for a more favorable ratio of toilets in coach class (one per 17 passengers) than in first class (one per 20 pax).  Overall, with five toilets for 90 passengers, that is an average of one per 18 passengers.  At some point, clearly Qantas chose to have more coach and fewer first class seats.

Or, as a comparison staying with Qantas, a modern Qantas 747-400 has six – eight toilets for 270 – 275 coach class passengers – one per 34 – 45 passengers.  Its new A380s have eight toilets for 332 coach class passengers (one per 42) or, in the latest A380s, a mere five for 374 passengers (one per 75).  Even Qantas is getting tangibly crueler and crueler.

For many more actual airplane examples, please go to our separate article that analyses toilet/seat ratios from the dawn of the jet age through to the latest A380s.

Summary

The shorter the flight, the fewer the toilets that are needed on a plane.  Long flights ideally should have at least one toilet per 40 passengers, and all planes should have at least two toilets (to allow for one becoming unavailable, for whatever reason).  Some planes have close to this number, but a significant number have massively fewer, with the inevitable result being long lines and unhappy passengers.

Unfortunately, while many things are regulated on airplanes and the airlines that operate them, the regulatory authorities seem to have a blind spot when it comes to something that is as essential a part of your traveling comfort and convenience as anything else.

Legislation is required to mandate acceptable toilet to passenger ratios, and also to require that the toilets not only be installed but be fully functional prior to any flight being cleared for takeoff.