Used Rheem water heaters can be purchased online from discount retailers such as Amazon as well as from auction sites such as eBay. Local classifieds sites such as Craigslist also frequently contain listings for used Rheem water heaters, though type and availability vary by region.
Listings for used Rheem water heaters on Amazon contain information about the unit, such as its features and functions, pictures of the unit and customer reviews. Each review consists of a quantitative satisfaction rating, in form of one to five stars, and a written account of the customer's experience with the product. While Amazon does not require its users to purchase an item in order to write a review, it does add an "Amazon Verified Purchase" tag to those reviews written by a user who has purchased the item directly through Amazon.
Sites such as Craigslist and eBay do not contain product reviews because each listing is unique to the seller. While eBay does feature a seller rating system, which allows users to provide feedback on a seller after completing a transaction, Craigslist does not because it doesn't require users to create an account in order to post on the site. As such, buyers should exercise caution whenever meeting a Craigslist seller in person.