A molecularly trichloroacetic acid (TCAA) imprinted non-crosslinked polypyrole (TCAA-MIPpy) has been successfully prepared and evaluated in its properties for both piezoelectric quartz crystal microbalance (QCM) and electrochemical means of detection, and application of such sensors for determination of haloacetic acid concentrations in water. Haloacetic acid selectivity was demonstrated in gravimetric or in electrochemical sensors via either cyclic voltammetric or interdigitated conductometric (IDC) analyses studies upon comparison with nonimprinted polypyrrole and TCAA-imprinted polypyrrole. The measurement results with all these systems revealed that the prepared molecularly imprinted polymer can recognize TCAA well from structurally similar compounds. The TCAA-MIPpy incorporated with only the IDC transduction system produced the specific signal for TCAA detection in aqueous environment, which is useful for the quantifying TCAA disinfection by-product in water. The analytical application for determination of TCAA in real-life samples was readily achieved with the incorporation of TCAA-MIPpy in the IDC analysis system, the results revealing the high sensitivity and selectivity of the method.