INTRODUCTION: Diarrheal disease contributes to an estimated 1.5 million deaths each year, including 760,000 deaths among children under the age of five. Of those, approximately 500,000 are attributable to inadequate drinking water. In areas where piped water is unsafe, unreliable or economically impossible, packaged water sold by private vendors can play an important role in meeting the water needs of these populations. As the activity and importance of packaged water vendors grow, more data is needed to assess the quality of water sold, and to inform policies that regulate the private water sector throughout the world. AIM: This pilot study seeks to identify factors that may contribute to the deterioration of packaged water quality. METHODS: Small packaged water enterprises (SWEs) operating in the following cities were visited twice between May 2014 and September 2015: La Paz, Bolivia; Tegucigalpa, Honduras; and Muisne and Tena, Ecuador. A brief survey was conducted with each distributor, and a facility tour was completed. Water samples were collected directly from the purification system and water packaged in both reusable and disposable containers were purchased. Samples were tested for total coliform and E. coli bacterial contamination on the day of collection and over the course of 28 days. Data was analyzed using descriptive statistics, including median as the measure of central tendency, and frequency where the main outcome was presence or absence of either total coliform bacteria or E. coli. To determine the factors that were most associated with water quality deterioration, logistic regression was performed. RESULTS: A total of 616 samples were collected. This study found that 52% of the packaged water examined was contaminated with total coliform bacteria. Raw, untreated water and treated water packaged in reusable containers were most likely to be contaminated with total coliform bacteria and E.coli compared to treated water taken directly from the system. There was no significant association between water treatment or bottle disinfection protocols and total coliform or E. coli contamination. DISCUSSION: The study succeeded in identifying at what stage and in what type of container water is most likely to be contaminated with bacterial water-quality indicators. Furthermore, it highlights the heterogeneity that exists in terms of types of water sold, water treatment systems, and sanitizing protocols among SWEs in Central and South America. Reusable containers are vulnerable to contamination with total coliform bacteria and E. coli, even when filled with clean water, thus the contamination may be due to inadequate disinfection between uses. These results may have implications for national or international policies that regulate private water enterprises, and can inform guidelines for packaged water distributors in particular. Further research is needed to identify optimal cleaning methods for reusable containers that are practical for use in lower resource settings.