Water Cherenkov Detectors (WCDs), which are part of the LAGO experimental array, are being built in the cities of Riobamba, Quito and Cumbaya in Ecuador. In order to increase the sensitivity and efficiency of these devices, it is necessary to ensure that the water used as radiator media absorbs as low as possible the UV light due to the incident particles and produced by Cherenkov effect. To do this, we built and used a device that allows us to measure the attenuation length directly. Water samples purified by different techniques are analyzed. Some characteristics like absorbance, refractive index, conductivity and cost are studied. We attempt to simulate the Cherenkov effect in FLUKA, we report our findings and perform a comparison with results from previous reports of LAGO sites elsewhere, and with other experiments that use WCD technology.