Lullington Road is currently closed both ways from Alfriston Road to Back Lane, in addition to Clapham Lane which is closed from the A259 to The Plough and Harrow pub.
Footage of Alfriston Road shows cars driving through flood waters by the Drusillas Park entrance.
Meanwhile, North Street has been impassable both ways since Thursday evening, according to the AA.
Earlier today, a motorist was rescued by a tractor after their car became stuck in the water in North Street.
East Sussex Fire and Rescue Service said: “We were called at 13.11pm to North Street in Alfriston, where a car had got stuck in water. A tractor had been able to reach a person in car prior to the arrival of crews.
"It is clear a number of roads are dangerously flooded due to the heavy rainfall.
“We would ask that you avoid travelling if possible, and do not assume that you will be safe because you are familiar with the roads.”