The amount of time fleas can survive without feeding varies from several days to two months depending on the humidity of the environment. Fleas thrive in humid environments.
The Pet Shed Petcyclopedia explains that a flea can live for a little over 130 days when it has access to a host. When a flea loses its host, it must find a new one as quickly as possible. According to 1-800-PetMeds, a little over half of newborn fleas may be able to survive for two months without a host if their environment is humid enough. On the other hand, newly hatched fleas in a dry and cold environment usually survive a few days at the most without feeding. Unfortunately, starving fleas of blood by removing their hosts is not considered a viable control method. Like other parasites, fleas always find new ways to adapt to their surroundings, and it only takes a few hardy individuals to build a booming population. The Pet Shed Petcyclopedia shares an unsettling statistic about how little it takes for a flea infestation to take over a house: as long as their environment is humid enough, just ten female fleas can become a quarter of a million within one month.