Take A Bloody Dip In Capcom's London Zombie Pool

[Gilhelmi]

due to every single regulation ever, i HIGHLY HIGHLY doubt that it will be ACTUAL blood in the pool. standard chlorine treatments wouldn't purify the blood, and... i don't even have to explain it, but rest assured, i will eat my own eyeballs if this turns out to be ACTUAL blood.

Yeah, there is no way in hell this is real blood of any kind.

my guess is that it's just regular pool water with some sorta thickener and red colorant
where the jesus would they get so much real blood anyways =P

Slaughterhouse, they could use pig or cow blood. I do not think they will, because it will be a PR disaster (pushing an EA class of insanity).