any of rio's beaches may have polluted waters within 24 to 48 hours following heavy rains.

getting to the beaches in the baía de sepetiba (sepetiba bay)can take two hours each way from rio's zona sul, and we recommend starting the day very early due to intense traffic.   

for first time visitors, the best way would be via taxi, which could be expensive unless divided 4-way - the maximum number of passengers allowed in a taxi.