Increasing amounts of wastewater are reeled for human use. Neither the natural mechanism of virus inactivation, which vary from water to water, nor the methods used by man for water purification can guarantee the complete elimination of infectious viruses. Although the importance of the presence of human viruses in waters has not been fully stablished as the cause of viral infectious diseases, it becomes evident that the evaluation of viruses in waters is of major relevance. Such evaluation presents a great deal of difficulties, the most important one being the lack of indicator cells for the majority of human enteric viruses. So far, only Enteroviruses are well evaluated. The usual need of virus concentration prior to the evaluation of the viral load is another difficulty. There are a good deal of concentration methods which represent the main difference among the procedures used to evaluate the amount of virus in waters. Using the technique of adsorption-elution on glass powder and BGM cells as indicator system we have been evaluating in the last years the presence of Enterovirus in superficial waters in Barcelona and Surroundings. Poliovirus, Coxsackievirus and Echovirus have been detected either in the rivers (Llobregat and Besos) and in seawater.