Septic tank has not needed to be unclogged for over 10 years in 7 apartment building. 8 months ago septic tank was clogged. They said it was due to cooking grease build it up. Today the septic tank needed to be unclogged again. How much grease would it take to do this? Is it indicative of a tenant pouring large quantities of grease down a drain?

If you did not pump out the septic tank for ten years chances are that considerable grease has migrated out down to the leach field, clogging that. If the leach field gets clogged you need to build a new leach field next to it or dig up the leach field and put down all new sand, drainage pipes (fingers), etc.

The septic tank normally has liquid up to about 85% full which usually translates to about 9 inches below the underside of the lid. Leach field problems are usually signified by the septic tank remaining absolutely full and possibly overflowing to the surface via non-hermetically sealed hatches.

Excess grease being put down the drains usually shows up as an abnormally thick layer of scum on the surface of the liquid in the septic tank.

This time 8 months later, was there a lot of solid, semisolid, and/or gelatinous material in the septic tank proper?



Edited 2 times.

I was just told that the septic tank needed to be unclogged again, the second time in 8 months, due to cooking grease. Does this automatically mean a tenant is pouring large quantities of cooking grease down a drain? More then just from regular cooking?

If you have 7 tenants, all with kitchen sinks, I would guess that you couldn't blame just one tenant.

Grease, laundry soaps and bleach, are NOT GOOD for septic systems. 8 unit apartment is very hard on a septic system if it wasn't engineered and serviced properly.

Best Wishes