I believe we have a cesspool with one overflow tank. House was built in 1960 and the overflow was added in the 70's. My wife and I bought the house from her family in 1982. We have a family of five. We have never had to pump our system since having moved in. Our next door neighbor is pumped every year or two. Living on Long Island, I assume our system is in very sandy soil, while my neighbor must have more clay. Just last summer we saw some slow down in draining of the washing machine. It is a large capacity model and we do about a load per day. We went light on our water usage and then away on vacation for 3 weeks. When we returned all was draining fine. We are now getting backups again if we use the washing machine. For a few weeks we've (my wife) done the wash at the laundromat. No backups for the rest of our drainage needs. I see my options as follows: 1) Install (myself) a 300-500 gal drywell (with blocks) for the washing machine. 2) Have the cesspool and overflow tanks pumped. 3) Add some enzyme and bacteria type treatment. 4) Add Septic-Scrub to the system. 5) A combination of the above. Any thoughts that you have on the matter would be greatly appreciated.