Sounds great. Except that as a company, you can now only deliver services to this government. No products, since you will lose your competitive advantage. This is a big disadvantage for for instance startups that target this market.
In Belgium it is mandatory for new houses to collect rainwater from the roof and use it for your toilet or washing machine, or to use a special well to let it soak into the ground slowly. This is quite cheap actually. The main purpose is to avoid this rainwater to come into the wastewater system.