Rectangular-shape reservoir for use in selective catalytic reduction system to store aqueous urea solution for post-treatment of exhaust gas in combustion engine of motor car, has sensor device with volume that contact with resistor chains

The reservoir (1) has a sensor device (2) arranged at outside of the reservoir for determining a filling level of a reducing agent i.e. aqueous urea solution. The sensor device exhibits resistor chains (3, 4) and volume (6) communicating with an inner space (5) of the reservoir. The resistor chains include a high impedance conductor (7) i.e. resistance wire, with mutually spaced pins (8) for an electrical contact of the resistor chains with the volume. The volume exists in a pipe or hose (9) that is made from plastic, where the pins are over-molded from plastic material of the pipe or hose.