What is this hole in my basement?

January 5, 2010 2:48 PM

What is this hole in my basement? and what should I do?

asking for a friend.... he says he's had his girlfriend flush the toilet upstairs and he doesn't notice any change in the hole. It's apparently very thick and black, very oily, maybe a little sewagey. To the right of the hole in the picture is the oil furnace, to the left a bathroom that no one uses. House was built in Vancouver in 1952. He's trying to get the rest of the stuff out now...
link to pictures

posted by imaswinger to home & garden (7 answers total)

Isn't that just a basement sump?

The oil is due to all the oil that has washed down there over the years.
posted by dunkadunc at 2:53 PM on January 5, 2010

If it's a sump, I'm curious about the drain pipe running into it.

Has he already located his sewer pipe and the soil stack for the bathroom next to the hole?
posted by SpecialK at 3:15 PM on January 5, 2010

There are some good answers in that forum, despite the eye bleeding crap all over the page. It's a sump, but I'd be a little worried about all that oil. Is that tank leaking?
posted by fixedgear at 3:37 PM on January 5, 2010

it might be a access to a old storage tank for the oil furnace maybe? or possibly the top of a septic system? I think you need a professional (plumber probably, but a good general contractor should know also)
posted by bartonlong at 3:46 PM on January 5, 2010

Could it be a grease trap? Usually found in restaurants and commercial kitchens. But if it were a grease trap it would smell more than a LITTLE foul.
posted by mbarryf at 4:08 PM on January 5, 2010

It's a sump pit or maybe a ejection pump sump. The pipe coming in and down could be a sewer pipe or it could be tile drainage pipe. The large flat thing could be a clean out cover plate; they are usually secured to a clean out bung/cap with a screw in the centre. Kind of a weird place for a clean out but I've seen a lot weirder. I wonder if there didn't used to be a vent or stack thereinstead of the clean out.

Note also there what appears to be an additional pipe or possible two coming in above the featured pipe. That would be indicative of tile drains into a sump well but lots of people have (incorrectly and dangerously) added sewage ejection pumps into sump well when remodelling. Getting the rest of the muck out and some pictures from the side would help with identification.

What's it smell like? Black sewage sludge is going to smell like, well, sewage. Oil from an oil furnace is usually lighter in colour but it could have 50 years of dirt mixed in with it and will smell like diesel or kerosene. It'll be really tough-to-impossible to wash the smell out too so avoid getting it on yourself. Personally it doesn't look like fuel oil to me, the rainbow diffraction pattern seen in the first pic points to small traces of oil on water.

As to cleaning it up: Scoop out as much as you can (plastic margarine containers and their assorted cousins work well for this) placing the material into ideally 20L buckets containing clay kitty litter but garbage bags with kitty litter will work too. Consider double bagging.

Half fill a wet/dry shop vac with kitty litter and then vacuum up the remaining (you can rent vacuums for dealing with grossness like this at tool rental places that have garbage bag like liners).

He's got to figure out whether the water returning is because of water use in the house or external sources. That'll let him know who to proceed.
posted by Mitheral at 4:08 PM on January 5, 2010 [1 favorite]

thanx, I'll him do exactly that.
posted by imaswinger at 11:42 PM on January 5, 2010