The sewer topic comes up repeatedly with pool owners who fill pools but the water never sees the sewer, but the owner is still charged a sewer fee based on metered water consumption. Most municipalities have a couple of remedies for this: 1. Have the water trucked in 2. Some communities will allow a separate metering from the fire system 3. Some can make an allowance based on some type of a waiver for pool filling.
Nonetheless, if sewer fees are based on water consumption, and the sewer is being used but no water, it still stands to reason there is a liability for the cost of the sewer to the user. As an aside, our township for years charged a "mini sewer" charge on our water bill to help offset sewer usage. This was irksome since I was on city water but there was no municipal sewer within a mile of my house. This was taken to court and found to be illegal since residents were being billed for a service that was not available to some.
I think if you want to live off grid or have some special amenities, your best course of action is to live in a municipality that embraces that. Having lived in several states and municipalities over the years, some are more intrusive to your residence than others are. The municipality will generally win since they usually have researched their legal standing, while you are going on what makes sense.
