First Guess: Copper washers on the brake hoses. A) there's two per bolt, not one. B ) the washers work-harden when the bolt is tightened, they should be replaced not re-used.
Second Guess: Loose or defective bleeder screws.
Third Guess: Someone disabled the park brake, the calipers won't adjust properly.
Beyond that, wash it off, fill the brake reservoir, and have someone start the engine (to get power to the brake booster) and stand on the brake pedal while you look for fresh leakage.