Given average water use per person in US is 310 liters/day (82 gallons) [1] and average electricity cost/kwh is $0.17 [2], and assuming 14 kJ/kg. 310 * (14 / 3600) * $0.17 = $0.20.
This study found these uses for indoor residential use:
18 gpd toilet (~10 flushes),
15 gpd washer (~1 load every few days),
11 gpd shower (~5 minutes),
11 gpd from faucet (~5min of flow, this one surprises me),
9.5 gpd from leaks,
1 gpd dishwashing
that's 65gpd right there. A ten minute shower and slightly more frequent laundry would easily get you 82gpd on indoor use only, ignoring any irrigation / outdoor use.
10 toilet visits a day but only 5 minutes in the shower? Either this is an entire household and it stinks to high heaven in there because no one actually washes themselves, or it's a single person and they need to see a doctor because they're going to the toilet way too much. SO either way, those numbers make no sense.
Perhaps in the sense of "on average, families have 1.6 children" (or whatever it is) — i.e, these are aggregate numbers, not to be taken as specific examples of actual households. Interpreting statistics can be tricky like that.
Also, to be fair, that study (I briefly looked) just lists toilet per-capita GPD in the quoted section ("Daily Per Capita Use"); it does not equate it to a number of flushes. They do have a whole section devoted to toilet flushes though — see "ULF Toilet Savings".
Cool! Showers are 2gpd minimum, so if you think someone is likely to take a longer shower then you should definitely agree that 82gpd is not "wild", per the post I was replying too. Glad we're in agreement, and thanks for being so polite!
Looking up large metropolitan water suppliers' average water treatment rates and service area sizes, ~80 gallons/person/day does seem to be a reasonable year-round average for total water consumption. (Although note that water usage is deeply seasonal--you might see 2× water consumption in summer as you do in winter).
I need to see a median number because 82 gallons indeed sounds outrageous for a consumer. Unless it is all-in calculation (agriculture + industry + consumers): America uses XXX units of water per year / # Americans.