field or holding-tank type of system that likely has access or clean-out points, vents and a straight-line connection to the home plumbing system. usually a pump helps the system process as needed, but some older systems might work based on gravity alone.
you might have a faucet that drips or leaks a bit. sometimes the needed fix is a new o-ring or washer, which are the rubber seals found beneath the spigot base and each of the knobs. if you want to do it yourself, first turn the water off to the sink and stuff a rag into the drain, so no little parts fall down. usually the screws to loosen 