I bought a circa 1952 house two years ago. It has a cesspool and what I believe is a drywell in the basement which a utility sink empties into. All of a sudden within the past week the utility sink draining has slowed to a crawl. I have checked the pipes for clogs and they are clear. The sink is used only for grey water drainage (laundry). I was surprised by the speed at which the draining slowed. Is this normal and what are my options. Thanks.