Are women's public restrooms dirtier and/or more bacteria-laden than the men's rooms?

Question

When a friend was posting an article about a proposed shared wall of stalls between the men's and women's sides where the doors only opened from one side at a time to provide load-sharing (yes, he pointed out his pun), I trotted out what I "knew" as fact, that women's bathrooms are less clean than men's rooms everywhere but bars. Then, I found myself questioning whether I was just perpetuating the myth. There were a lot of personal anecdotes, but little hard data.

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http://numbertwoguide.com/womens-restrooms-the-dirtiest/

Now, I know five out of six toilets being clogged is rather high. Personally, I haven’t come across a number like that in any public toilet I’ve been to. So it got me thinking: are women’s public restrooms more inclined to be stinky, clogged, and all-around dirtier than men’s? Yes.

Here is the general list of reasons why they’re dirtier:
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http://www.pcccourier.com/2013/10/23/watercloset/

Who has the cleanest restrooms: men or women? The ultimate judges should be the people responsible for cleaning them up.

It is believed that women are naturally tidier than men but one look into the women’s restroom will change that belief.

“The women’s restrooms are a lot dirtier because of the feminine products and they just throw everything on the floor,” said facilities worker Desiree Ramirez.

http://wc.arizona.edu/papers/90/156/07_1_m.html

While men's restrooms smell worse and contain more litter than women's restrooms, women's restrooms actually contain more fecal bacteria than men's. Fecal bacteria, found in the intestinal tract, are an indicator of the potential presence of other disease -causing organisms that shed from the intestinal tract.

Kennedy discovered a two-to-one ratio between the bacteria in women's and men's bathrooms, which means there are more bacteria in women's bathrooms to cause sickness.

"I didn't expect women's restrooms to be so much higher in bacteria than men's," Kennedy said.

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Besides so much of the evidence being anecdotal, I also find myself a bit skeptical about how the more scientific studies rely on a general "bacteria count", a measure which is often deceptive of the actual risk. Is there any evidence that one side has it worse than the other in terms of restroom cleanliness?

Answer 1

A study done ⁽¹⁾ by Ciri Science, the Cleaning Industry Research Institute, sampled 47 public restrooms to test the presence of bacteria on various bathroom surfaces and found that women’s bathrooms are 4.5 times more likely to have Escherichia coli bacteria in them, and that men's bathrooms are cleaner:

A comparison between the relative cleanliness of male and female restrooms (Table 8) showed that:

• Male restrooms were 1.5 times "cleaner" overall (1.5 times less total coliform contamination)

• Female restrooms the sink (around the drain) was three times more likely to be contaminated with E. coli than the sink drains of the male restrooms.

The trends are even more obvious when the toilet, sink, and floor areas were grouped for male and female restroom (Table 9).

The study indicated that women's bathrooms are dirtier than mens in all area:

In frequency of total coliform occurrence, women out-do men nearly 2:1 in all areas. More specifically, in female restrooms, the floor area was 1.6 times more likely to be contaminated, the sink area was 1.9 times, and the toilet area was 1.8 times. The frequency of E. coli isolation was also greater in female restrooms. The E. coli was 4.5 times more often isolated in the sink area of female restrooms. There is a similar trend for the toilet area. Toilet area sites were contaminated with E. coli 1.9 times more often in female restrooms.

Moreover, a recent study published in PlusOne⁽²⁾, pointed out that women’s restrooms are far more likely to have many more germs than a men’s restroom since Lactobacillaceae is clearly more abundant on certain surfaces within female restrooms than male restrooms. This is because the bacteria found in the vagina of healthy reproductive age women, and is relatively less abundant in male urine. Excerpt:

There were gender-related differences in the relative abundances of specific taxa on some surfaces (Figure 1B, Table S2). Most notably, Lactobacillaceae were clearly more abundant on certain surfaces within female restrooms than male restrooms (Figure 1B).

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^{(1) Enteric Bacterial Contamination of Public Restrooms: Created on December 22nd, 2007. Last Modified on June 3rd, 2010}

^{(2) Flores GE, Bates ST, Knights D, Lauber CL, Stombaugh J, et al. (2011) Microbial Biogeography of Public Restroom Surfaces. PLoS ONE 6(11): e28132. doi:10.1371/journal.pone.0028132}