Evaluating the Effectiveness of Point-of-Entry UV Treatment for Cistern Water among Households in the US Virgin Islands

Abstract

UV water treatment can be a viable option for point-of-entry applications among households utilizing contaminated private water sources, including roof-harvested rainwater. However, limited data is available on UV system effectiveness and costs. Therefore, Love City Strong, an NGO in the US Virgin Islands, piloted a UV access program which included free UV systems with prefiltration along with installation and monthly household visits for up to 12 months, including water quality testing. In addition, a pilot study was conducted to evaluate the effectiveness of UV systems without prefiltration. Results from the UV access program demonstrated that E. coli was not detected in 95.1% of tap or spigot samples (n = 268). Among water quality parameters, household characteristics, and premise plumbing dynamics, no factor was significantly higher among samples with detections of E. coli or total coliforms. Among all samples from the pilot study of UV systems without prefiltration, no E. coli was detected (N = 24). Finally, there was a wide range of costs─first year and annual─when comparing different types and configurations of UV systems. Given these data, UV systems may be a viable option for generating potable water; however, clear purchasing and operational guidelines are important to reduce user error.