A novel compact RF sensor based on a Complementary Split Ring Resonator (CSRR) for the detection of impurities in liquid samples is designed, developed, and experimentally validated. The sensor uses changes in dielectric permittivity to measure the levels of impurities in common liquids and operates at 2.4 GHz. Two sensor configurations were designed and tested, with different dimensions. The sensor structure’s form is intended to achieve increased sensitivity. Because it makes use of the bent form configuration, the sensor structure is fairly compact. The manufactured sensor prototype has a sensitivity of 39.36, which is significantly higher than the sensors found in the literature. A case study was conducted on milk, with water and vegetable oil as impurities and changes in resonant frequency is measured. The sensor provides a 100 kHz shift in the resonant frequency for 50% adulteration. The sensor’s compact design, ease of fabrication using a low-cost FR4-Epoxy substrate, and high accuracy make it a viable alternative for non-destructive impurity detection in food safety, healthcare, and environmental monitoring applications.