when did you realized that u poured water instead of petrol? did u try to start car after that? if no than u can try disconnecting the petrol supply from fuel filter(usually at under body in case of suzukis, don't know about others) or try disconnecting from throttle body an water will be drained when u will switch on car,,however these tricks can cause engine seisure if water somehow get to the throttle body,, fuel tank removal methode is best as it will eliminate any chance of water entering throttle body