Lower disinfectant concentrations cause the bacteria to develop resistance more quickly.
Bacteria and other microorganisms exist all around us. Most of them are harmless to humans. Some assist us in digesting our food while others make us sick. This is why disinfectants should be used regularly to reduce the growth of these harmful bacteria.
However, disinfectant overuse leads to bacteria resistance, whereby the bacteria develops an immunity towards the disinfectant and makes it ineffective in killing the bacteria. This is also true for bacteria resistance towards antibiotics. This may lead to the growth and multiplication of a new population of resistant bacteria.