One of the factors/examples that can negatively affect online reviews from users of vacation rentals is bad odor from drains and drain pipes in bathrooms/kitchens/toilets, which users find unpleasant. For example, a foul odor like that of thirsty water may be generated from the bathroom drain.
Even if the bathroom is properly cleaned on a superficial level, if the drains and pipes are not properly cleaned on a regular basis, hair, fine soap scum, body oils, etc., will adhere to the drains and pipes, increasing the risk of a lot of germs. Germs can cause a foul odor like ditch water. In order to prevent this from happening as much as possible, it is necessary to clean drains and drainpipes regularly.