Hollywood heartthrob Zac Efron woke up to a flooded house after his swimming pool overflowed due to torrential rain.

The 'High School Musical' star, who recently spent one million dollars on a 'modest' Hollywood apartment, reportedly spent the entire day mopping up water damage.

'Zac called his pool guy, who arrived with a pump and started directing water away from the property,' said a source.

The 22-year-old actor had also called up a group of his closest friends to come over and help him repair the damage, reports contactmusic.com.

The source added: 'He and some pals spent an entire day mopping out his house and sandbagging doors to block further flooding. Now Zac's working with landscapers to design a better drainage set-up - and he just keeps thanking his lucky stars he was in town to stop further damage,' the source added.