This work investigates design criteria for an array of polymer-coated shear-horizontal surface acoustic wave sensors for detection of aromatic compounds directly in groundwater and wastewater. In addition to the sensitivity and selectivity issues, coating stability in water and long-term repeatability of the sensor response have been investigated. The compounds used in designing the coating have been selected according to their Hansen solubility parameters to ensure maximum chemical compatibility between the coating and the target analytes. The coatings' physical characteristics have been optimized to ensure high analyte uptake while maintaining low acoustic-wave attenuation and low spectrum distortion.