Fil: Poma, Hugo Ramiro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones para la Industria Química; Argentina.Fil: Rajal, Verónica Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones para la Industria Química; Argentina.Fil: Blanco Fernández, María Dolores. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Cátedra de Virología; Argentina.Fil: Barril, Patricia Angélica. Universidad Nacional de Córdoba. Instituto de Virología Dr. J. M. Vanella; Argentina.Fil: Giordano, Miguel Oscar. Universidad Nacional de Córdoba. Instituto de Virología Dr. J. M. Vanella; Argentina.Fil: Masachessi, Gisela. Universidad Nacional de Córdoba. Instituto de Virología Dr. J. M. Vanella; Argentina.Fil: Martínez, Laura Cecilia. Universidad Nacional de Córdoba. Instituto de Virología Dr. J. M. Vanella; Argentina.Fil: Isa, María Beatriz. Universidad Nacional de Córdoba. Instituto de Virología Dr. J. M. Vanella; Argentina.Fil: Freire, María Cecilia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: López Riviello, Gabriela. Prefectura Naval Argentina. Departamento Científico Pericial; Argentina.Fil: Cisterna, Daniel. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Nates, Silvia Viviana. Universidad Nacional de Córdoba. Instituto de Virología Dr. J. M. Vanella; Argentina.Fil: Mbayed, Viviana Andrea. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Cátedra de Virología; Argentina.Enteric viruses monitoring in surface waters requires the concentration of viruses before detection assays. The aim of this study was to evaluate different methods in terms of recovery efficiencies of bacteriophage PP7 of Pseudomonas aeruginosa, measured by real-time PCR, using it as a viral control process in water analysis. Different nucleic acid extraction methods (silica-guanidinium thiocyanate, a commercial kit (Qiagen Viral RNA Kit) and phenol-chloroform with alcohol precipitation) exhibited very low recovery efficiencies (0.08-4.18 %), being the most efficient the commercial kit used for subsequent experiments. To evaluate the efficiency of three concentration methods, PBS (as model for clean water) and water samples from rivers were seeded to reach high (HC, 10(6) pfu ml(-1)) and low concentrations (LC, 10(4) pfu ml(-1)) of PP7. Tangential ultrafiltration proved to be more efficient (50.36 ± 12.91, 17.21 ± 9.22 and 12.58 ± 2.35 % for HC in PBS and two river samples, respectively) than adsorption-elution with negatively charged membranes (1.00 ± 1.34, 2.79 ± 2.62 and 0.05 ± 0.08 % for HC in PBS and two river samples, respectively) and polyethylene glycol precipitation (15.95 ± 7.43, 4.01 ± 1.12 and 3.91 ± 0.54 %, for HC in PBS and two river samples, respectively), being 3.2-50.4 times more efficient than the others for PBS and 2.7-252 times for river samples. Efficiencies also depended on the initial virus concentration and aqueous matrixes composition. In consequence, the incorporation of an internal standard like PP7 along the process is useful as a control of the water concentration procedure, the nucleic acid extraction, the presence of inhibitors and the variability of the recovery among replicas, and for the calculation of the sample limit of detection. Thus, the use of a process control, as presented here, is crucial for the accurate quantification of viral contamination.