Three things: 1. There are a bunch of environmental costs that still make them largely impractical: - the environmental cost of making the filters (plastic in

Three things: 1. There are a bunch of environmental costs that still make them largely impractical: - the environmental cost of making the filters (plastic injection molding, etc.) - the environmental cost of disposing of the filters - the environmental cost of waste produced by installing new waterless urinals in place of the old watered ones These costs are surprisingly high for something trying to be "green". You can model these positive externalities as such in a "dollar amount" by taking into account things such as offset taxes toward pollution (from manufacturing,) costs of disposal over the decomposition life of the object, etc. 2. Unfortunately, the environmental cost is almost never the one that wins in any real-world scenario unless the personal utility of the person owning said waterless urinal is greater than the cost of running the watered one — i.e., the person that installed the waterless urinal enjoys the waterless one enough to compensate for the extra costs involved in running it over a watered one. They are more expensive right now, and will be for quite some time if we're talking about replacing the watered ones with waterless ones. Dollars are the bottom line, especially when negative externalities are not offset in the costs of the watered product. 3. I'm a general skeptic of many of these types of green things due to #2 - it's the "Prius syndrome" in effect. Many of these types of things have little real-world environmental impact when the full cost of ownership is taken into account. Once you add up all of the costs involved: (manufacturing costs of old watered urinal) + (disposal costs of old watered urinal) + (opportunity cost of purchasing waterless urinal and installing waterless urinal) + (cost of new waterless urinal) + (cost of filters) * ((uses / single filter life) * (life of waterless urinal product)) When all is said and done, the overall real cost - even environmentally - of many of these "green" products ends up being far greater than just using the old product. People don't buy many of these types of things for anything other than their own psychological benefit of feeling greener, such as is the case with the Prius - I read somewhere if you actually wanted to maximise for environmental cost, you'd buy a used Toyota Echo.