Industry will always lead the way in the adaptation of new technology, and especially the technology of conservation. This is not necessarily for any ideological reason, but because the people who manage water use better understand the economic incentives for adopting new technology. Current technology of wastewater treatment is a perfect example of this acceptance of environmentally beneficial processes in the pursuit of increased profitability.
The root of this profitability is generally in going above and beyond what is required. Most municipalities will require some degree of process wastewater treatment before they will accept discharge into a municipal wastewater system. The discharge permit, however, will come with limits on discharge into the system simply out of necessity, and each gallon of discharge comes with a price tag attached. The unit cost of this discharge can be about $5 (USD) per 1,000 gallons (3,785 liters) of treated wastewater discharged to a municipality for further treatment. In some jurisdictions, it can be noticeably higher. The pragmatic consequence of cost is that on-site treatment only needs to cost less than regulatory sewer discharge cost, which might approximate $5 per 1,000 gallons, to return treated waste water to an environmentally acceptable state to be economically advantageous. Discharging water into an environmental waterway is free once it passes US EPA regulations for safe discharge quality and quantity into receiving waters.