^Actually, it's all dependent upon each individual showeree whether or not a bath or a shower would save more water. It's not a given that taking baths is more wasteful than taking showers.
There are several issues with this statement. 1) The EPA is taking the measure of a bathtub's maximum capacity, in other words, the amount of water it could hold until its limit breaks. Placing a body of mass in the bathtub after that point would cause the water to rise above its containment limit, as the original measurement of full capacity only works when no other mass is present in the bathtub. How many people fill a whole bathtub when taking a bath and plop themselves in, causing the water to disperse and soak the entire bathroom floor? Not many (not any, I'm hoping, but with people one never knows...). 2) It is not taking into account individual bathtub water level preference, or time taken to bathe as opposed to shower. I, for example, only fill my tub halfway when taking a bath, and my baths last from 45 minutes to 1 hours and 25 mins. My showers, on the other hand, take 30 to 45 minutes. If I only fill my bathtub halfway, I would be taking an hour-long bath and only using 35 gallons of water. Were I to shower instead, I would be using, say, 15-20 gallons of water every 5 minutes (I have an older shower head, so it's not equipped for water conservation). Since my showers take a minimum of 30 minutes, at a rate of 15 gallons every 5 minutes, I would have wasted 90 gallons of water (15x6). Even if I were to cut that time in more than half, say--taking a 10 or 15 minute shower-- the rate of water wasted for 10 mins. would be (15x2-20x2= 30-40 gallons), and for 15 mins. (15x3-20x3=45-60 gallons). In either of these adjusted instances, the shower takes up more water than the bath, and lasts less time.
Extraneous, but interesting: aren't both baths
and showers typically used by one person at a time? The EPA is really idiotic, lol--nice try at manipulation, but no cigar.
The only way one could waste less water in taking a shower as opposed to a bath is by restricting shower time to way under 10 minutes, as close to five minutes or under.
I don't know anyone who takes a good, hygenic shower in less than ten minutes, so a five minute shower really sounds ridiculous to me. It takes five minutes just to get my thick, curly hair wet enough for the shampoo to work. 
Therefore, if I were to limit my showers to five minutes, I wouldn't even be taking a real shower. I'd just be wetting my hair, that's it.
So, really, there are compelling arguments for or against showers and baths, but the advantage of one over the other really depends upon individual factors.
