If the infrastructure is available, it had to be built, and someone paid for it. If there wasn't a hookup before, then it seems reasonable to pay the full share to recoup the investment, even if the line is right there. Otherwise the infrastructure investment would have to be paid by someone else, or from other taxes.
These days, septic should be disallowed, if a reasonable sewer is available, as these days the effluents contain all kinds of toxic and non-degradable stuff that poisons the land and ground water. Over here, lossy septic tanks are illegal. You can either hookup to a sewer, treat your wastewater in situ via certified processes or, under some conditions, use a non-draining septic tank and have the wastewater treated.
These days, septic should be disallowed, if a reasonable sewer is available, as these days the effluents contain all kinds of toxic and non-degradable stuff that poisons the land and ground water. Over here, lossy septic tanks are illegal. You can either hookup to a sewer, treat your wastewater in situ via certified processes or, under some conditions, use a non-draining septic tank and have the wastewater treated.