[en] This study focuses on assessing the microbiological quality of drinking water and of water intended for drinking in the province of Valencia (Spain) between 2002 and 2010. Variation was found regarding space, time and source requirements in samples that did not meet the standards of quality established by Royal Decree 140/2003 for the following: total coliforms (TC); faecal coliforms (FC); Escherichia coli (EC); aerobic bacteria at 22 °C (AB 22 °C); faecal streptococci (FS); enterococci (EN); sulphite-reducing clostridia (SC); and Clostridium perfringens (CP). The samples were stratified by those meeting the standards ("Compliance") and those that did not ("Non-Compliance"), as well as by their relationship with the degree of chlorination.A total of 10057 water samples were examined from various sources: springs; surface waters; denitrifying plant waters; wells; and distribution networks. They were grouped into each of the 17 districts of the province of Valencia.The total number of samples that failed to meet the standards of quality, for each criterion, were as follows: 34.0 % for TC; 16.0 % FS-EN; 13.0 % for FC-EC; 5.6 % for SC-CP; and 15.5 % for AB 22 °C. Regarding spatial variation in samples, the highest percentages of samples in the "Non-Compliance" group were found in the interior part of the province. For time variation, the highest percentages of "Non-Compliance" were for the years: 2002 - 2004, 2008 and 2009. Regarding source variation, origin of the samples with "Non- compliance" was highest for surface waters, followed by springs and wells.For all samples studied, 39.8 % were within the "Non-Compliance" group, of which 18.3 % came from sources that supply the population (distribution networks).Of the samples within the "Compliance" group, 61 % were chlorinated, which confirms that chlorine is a powerful disinfectant and that chlorination is an effective water disinfection treatment.

[es] El presente trabajo tiene como objetivo la evaluación de la calidad microbiológica de las muestras de agua analizadas en la provincia de Valencia durante el período 2002-2010. Se observó la variación espacial, temporal y por origen de las muestras que no cumplían los requisitos especificados en el RD 140/2003 para los coliformes totales (CT), coliformes fecales (CF), Escherichia coli (EC), aerobios a 22 °C (AB 22 °C), estreptococos fecales (EF), enterococos (EN), Clostridium sulfito reductores (CS), y Clostridium perfringens (CP), estratificando las muestras en aquellas que cumplían la normativa "Conformes" y las que no "No Conformes", y su relación con el grado de cloración.Se estudian un total de 10057 muestras de agua procedentes de fuentes que no manan de la red, aguas superficiales, aguas provenientes de plantas desnitrificadoras, pozos y redes de distribución. Se han agrupado en las 17 comarcas de la provincia de Valencia.Del total de las muestras, no cumplían los requisitos de calidad para CT el 34,0 %, para EF-EN el 16,0 %, para AB 22 °C el 15.5 % para CF-EC el 13,0 % y para CS-CP el 5,6 %. Los porcentajes más elevados de muestras "No Conformes" se observaron situados en la zona interior, y en los años 2002-2004, 2008 y 2009. Respecto a la distribución por origen, se observaron en aguas superficiales, seguidas de fuentes y pozos.Del total de muestras estudiadas, el 39,8 % eran "No Conformes", y de estas un 18,3 % procedían de abastecimientos que proveen a la población (redes de distribución).El 61,0 % de las muestras "Conformes" estaban cloradas, lo que demuestra que el cloro sigue siendo un tratamiento efectivo de desinfección.