The inevitably high energy consumption of traditional electrochemical processes to treat low-conductivity water has limited their wider application. Herein, we present an energy-efficient alternative, i.e., a Ti4O7 reactive electrochemical ceramic membrane (Ti4O7-REM) system with a superior mass transfer ability. For the removal of 10−200 μM norfloxacin (NOR) from low-conductivity (178−832 μS cm−1) water, the Ti4O7-REM system increased the kinetics rate constant by 4.3−34.0 times, thus decreasing the energy cost by 80.5−97.3% compared with a flow-by system. The rapid NOR removal was related to the enhanced direct electron transfer process in the Ti4O7-REM system, which allowed for higher resistance to HCO3− scavenging and a favorable reaction between NOR and the active sites. Meanwhile, this mechanism likely contributed to the less formation of inorganic chlorinated product, ClO3−, in the presence of Cl−. Although organic chlorinated byproducts were not detected during NOR degradation in the Ti4O7-REM system, Cl– influenced the speciation of the intermediates. A single-pass Ti4O7-REM system demonstrated 94−97% removal of trace antibiotics from real water samples in 30 s. The additional energy consumption (<0.02 kWh m−3) using a Ti4O7-REM system only contributed to 5.0−6.4% of the total in a typical tertiary wastewater treatment plant. Based on the above results, we can conclude that the convection-enhanced REM technique is viable for the purification of low-conductivity natural waters.