Arsenic contamination of groundwater is a global problem that causes millions of people to put themselves at risk for many health related diseases. Arsenic poisoning has been linked to a variety of cancerous and noncancerous health effects, including arsenicosis. Current diagnostic technologies for arsenic detection are either inaccurate colorimetric methods, or expensive, offsite lab analysis. These tests are not user-friendly, and require the use of other toxic chemicals. Both colorimetric and spectrometric methods are unsuitable for resource-limited settings. To address this need, this projects aims to create a microfluidic sensor capable of detection a variety of contaminants in groundwater sources. This project focuses on the electrochemical detection of arsenic because of its high toxicity and distribution in the developing world. Our microfluidic sensors employs a three-electrode system patterned with conductive ink onto a glass substrate, enabling detection of arsenic in concentrations down to 5 parts per billion (ppb). Using a materials printer, the fabrication of the sensor is rapid, consistent, and inexpensive, allowing for the mass-production of sensors. When the sensor is inserted into a water sample and is connected to an electrochemical analyzer, various voltammetry sweeps are placed onto the electrodes, producing a current peak for arsenic ions present in the water. Using a mobile application, the user will know the exact concentration of the contaminant and have the option of viewing a map displaying other areas that have been tested with our sensors and if those areas can provide safe drinking water