A quantitative approach for calculation of the percentage of water of domestic wastewater origin in contaminated water wells is presented. The article is an extension of a reported approach to quantify leakage from a wastewater recharge facility to nearby water wells pumping predominantly from a pristine aquifer. The relative contamination from a specific source, a wastewater recharge basin, and the contamination from unspecified domestic wastewater sources under near steady state conditions are calculated for several water wells in the vicinity of a wastewater recharge system. Carbamazepine (CBZ), an antiepileptic drug whose refractory behaviour was reported before is evaluated as a tracer. It is demonstrated that CBZ fulfils the requirements of source-specific as well as non-specific wastewater tracer, under Israeli conditions. In addition to being biodegradation-resistant, a survey of the effluents of domestic wastewater treatment plants in Israel revealed that the CBZ level is roughly constant, 1407 +/- 204 ng/L in a wide range of water treatment facilities all over Israel. As such, at least for specific sites (e.g. Israel) CBZ can be used as a quantitative tracer for estimation of the fraction of effluent-originated water in water wells, and the uncertainty involved in such estimates can be calculated. (C) 2011 Elsevier B.V. All rights reserved.